Category Archives: Genetic Therapy

By the end of March, Vertex Pharmaceuticals and CRISPR Therapeutics expect to have submitted a U.S. approval application for a gene editing medicine designed to treat two rare blood disorders.

On Tuesday, the companies said the Food and Drug Administration is allowing a so-called rolling review of their medicine, named exa-cel, for the treatment of sickle cell disease and beta thalassemia. Filing is slated to begin in November, with a completed application anticipated some time in the first quarter of next year. In Europe, where Vertex and CRISPR are also seeking approval, the companies said theyre on track to file by the end of this year.

If approved, exa-cel would become the first marketed therapy based on the CRISPR gene editing technology that won a Nobel Prize in 2020. Data generated in clinical studies have so far shown that, for most patients, a one-time treatment with exa-cel significantly alleviates the symptoms and burdens of sickle cell and beta thalassemia.

We continue to work with urgency to bring forward the first CRISPR therapy for a genetic disease, and one that holds potential to transform the lives of patients, said Nia Tatsis, Vertexs chief regulatory and quality officer, in a statement.

Vertex previously aimed to submit a full application by the end of 2022, wrote Brian Abrahams, an analyst at the investment firm RBC Capital Markets, in a note to clients.Still, Abrahams and his team wouldnt expect a few months of difference in expected filing time to be material.

More concerning, according to the RBC team, is the potential sales outlook for exa-cel.

Several companies, including deep-pocked players like Pfizer, Novartis and Novo Nordisk, are trying to develop new medicines for sickle cell and beta thalassemia. And just last month, Massachusetts-based Bluebird bio secured FDA approval of a gene therapy another one-time, long-lasting treatment for patients with severe beta thalassemia who require blood transfusions. Bluebird is developing a gene therapy for sickle cell, too.

Additionally, the way exa-cel is administered could affect how many patients seek it out.

The medicine is made with a patients own stem cells, which are engineered and then implanted back into the bone marrow. The process requires patients be conditioned with busulfan, a chemotherapy-based regimen that can be difficult to tolerate. For example, one patient in the exa-cel clinical trial experienced bleeding in the brain that researchers attributed to this regimen.

CRISPR has said its exploring alternative conditioning procedures that dont involve chemotherapy. Even so, some analysts remain skeptical. Luca Issi, an RBC analyst who covers Beam Therapeutics, another company developing a gene-editing treatment for sickle cell, believes the commercial prospects for Beams program would be capped by its use of busulfan conditioning.

We remain cautious on exa-cel's ultimate commercial opportunity given our prior [conversations with doctors and patients], at least not until the much longer term once less toxic pre-conditioning regimens can be deployed, Abrahams wrote.

Vertex, meanwhile, has appeared more confident in exa-cels sales potential. Last year, the company paid CRISPR $900 million to amend their partnership so Vertex receives a greater portion of the profits should exa-cel come to market.

Read more:
Vertex given green light to seek US approval of CRISPR-based therapy - BioPharma Dive

Tenaya Therapeutics, Inc.

Encore Presentation of Lead Gene Therapy TN-201 Preclinical Data to be Featured in Late-Breaking Trials Session

SOUTH SAN FRANCISCO, Calif., Sept. 29, 2022 (GLOBE NEWSWIRE) -- Tenaya Therapeutics, Inc. (NASDAQ: TNYA), a clinical-stage biotechnology company with a mission to discover, develop and deliver potentially curative therapies that address the underlying causes of heart disease, announced today that it is scheduled to participate in the Hypertrophic Cardiomyopathy Medical Societys (HCMS) inaugural 2022 Scientific Sessions taking place September 30, 2022, virtually and in National Harbor, MD.

Milind Desai, M.D., MBA, Director of the Center for Hypertrophic Cardiomyopathy and Director of Clinical Operations, Heart, Vascular & Thoracic Institute at Cleveland Clinicwill present preclinical data for Tenayas TN-201, a gene therapy candidate intended to correct the underlying genetic cause of HCM, MYBPC3 gene mutations. Variants in the MYBPC3 gene are the most common genetic cause of HCM, believed to contribute to approximately 20 percent of all HCM cases. Whit Tingley, M.D., Ph.D., Tenayas Chief Medical Officer, will join an industry panel to discuss advances in genetic therapies and its potential in individuals with HCM.

Details of Tenayas participation are as follows:

September 30, 2022Time: 10:50 a.m. 11:10 a.m. ETSession: Late-Breaking TrialsTitle: Early Breaking Trial 3 Gene Therapy Candidate for Hypertrophic Cardiomyopathy Patients with MYBPC3 MutationPresenter: Dr. Milind Desai, Cleveland Clinic

Time: 12:15 p.m. 12:55 p.m. ETSession: Industry RoundtableSpeaker: Whit Tingley, M.D., Ph.D., Tenaya Therapeutics

The HCMS Sessions are intended to highlight the history, major developments and emerging concepts in hypertrophic cardiomyopathy (HCM), including learning about genetic forms of HCM and emerging treatments. A copy of the presentation will be posted to Tenayas website. To view full event programming, please visit the HCMS website.

Story continues

About TN-201 for MYBPC3-associated Hypertrophic CardiomyopathyTN-201 is an adeno-associated virus-based gene therapy being developed to treat hypertrophic cardiomyopathy (HCM) due to disease-causing variants in the Myosin Binding Protein C3 (MYBPC3) gene. HCM is a chronic, progressive condition in which the walls of the left ventricle become significantly thickened, leading to abnormal heart rhythms, cardiac dysfunction, heart failure and increased risk of sudden cardiac death, accompanied by symptoms such as shortness of breath, fainting and palpitations. Variants in MYBPC3 are the most common genetic cause of HCM, estimated to represent approximately 20 percent of the overall HCM population and to affect approximately 115,000 patients in the United States alone. In preclinical studies, following a one-time injection of TN-201 in a severely diseased knock-out model of MYBPC3-associated HCM, a reversal of cardiac dysfunction and improvement in survival was observed. Tenaya plans to submit an Investigational New Drug application for TN-201 to the U.S. Food and Drug Administration in the second half of this year.

AboutTenaya TherapeuticsTenaya Therapeuticsis a clinical-stage biotechnology company committed to a bold mission: to discover, develop and deliver curative therapies that address the underlying drivers of heart disease. Founded by leading cardiovascular scientists fromGladstone Institutesand theUniversity of Texas Southwestern Medical Center, Tenaya is developing therapies for rare genetic cardiovascular disorders as well as for more prevalent heart conditions through three distinct but interrelated product platforms: Gene Therapy, Cellular Regeneration and Precision Medicine. For more information, visitwww.tenayatherapeutics.com.

InvestorsMichelle CorralTenaya TherapeuticsIR@tenayathera.com

MediaWendy RyanTenBridge Communicationswendy@tenbridgecommunications.com

See the original post:
Tenaya Therapeutics to Participate in Inaugural Hypertrophic Cardiomyopathy Medical Societys 2022 Scientific Sessions - Yahoo Finance

Introduction

Huntingtons disease (HD) is an autosomal dominant neurodegenerative disorder with an estimated prevalence of up to 9 per 100,000 in the USA, Canada, Oceania, and Western Europe.1,2 HD is caused by a CAG (cytosine, adenine, and guanine) repeat expansion in exon 1 of the Huntingtin (HTT) gene, resulting in the translation of a mutant Huntingtin protein harboring a toxic polyglutamine (polyQ) stretch at its amino (N) terminus. Gene carriers with repeats between 36 and 39 CAG show incomplete penetrance, while repeats of 40 and more triplets lead to fully penetrant disease. The age of onset is inversely correlated with the CAG repeat length, with an average age of onset of 3544 years. HD is characterized by motor, cognitive and psychiatric symptoms and is ultimately fatal, with a median survival of 1518 years after onset. About 510% of HD patients show disease onset before 20 years of age, in which case it is called juvenile HD. Juvenile HD has a different clinical presentation compared to adult onset HD, characterized by symptoms such as severe mental retardation, speech and language delay, as well as more pronounced motor and cerebellar symptoms and overall more rapid disease progression.3

Apart from the inherited CAG length, several genetic modifiers have been identified that are associated with age of onset. Many of these modifiers point towards an important role for somatic instability: the process in which the CAG repeat within cells expands over time. Within the HTT locus, a strong genetic modifier is whether or not a CAA (cytosine, adenine, and adenine) interruption is present at the 3 end of the CAG repeat. Similar to CAG triplets, CAA encodes for glutamine, thus resulting in the same polyQ stretch. Nonetheless, alleles that lack this CAA interruption were found to be more prone to somatic expansion and showed decreased age of onset, while the presence of an additional CAA interruption was found to delay both somatic expansion and age of onset.4,5 Moreover, many of the identified trans-acting genetic modifiers, such as FANCD2 And FANCI Associated Nuclease 1 (FAN1) and MutL Homolog 1 (MLH1), are involved in DNA mismatch repair and influence somatic instability of the CAG repeat.5,6

Although HD was initially thought to be mainly a protein toxic gain-of-function disorder, it is likely that protein loss-of-function also plays a role, as reviewed elsewhere,710 and there is increasing evidence for the involvement of other disease mechanisms, such as repeat-associated non-AUG dependent (RAN) translation and RNA toxic gain-of-function, also reviewed previously.1113 Still, little is known regarding the relative contribution of each of these pathogenic mechanisms to the disease (Figure 1).

Figure 1 Schematic overview of the molecular pathogenesis of HD.

HTT is known to be essential for embryonic development, as demonstrated by the fact that knockout mice are embryonically lethal, and also appears to play a role in later stages of development and life, as reviewed by Kaemmerer and Grondin.10 There is, however, no clear consensus on the level of wild type HTT (wtHTT) that is required for its normal function, as this is likely to depend on many factors, including age and tissue/brain region. wtHTT is involved in many important cellular processes, including endocytosis and vesicular trafficking, cell division, autophagy and transcriptional regulation (reviewed by Saudou and Humbert)9 which may all be impacted by a loss of wtHTT function in HD.

Compelling evidence for the involvement of RNA-mediated toxicity was provided by Sun et al, who found that even in the absence of translation, there was still repeat-length dependent toxicity of 5 HTT mRNA as well as full-length HTT.14 RNA toxic gain-of-function is caused by the interaction between RNA-binding proteins (RBPs), such as Muscleblind like splicing regulator 1 (MBNL1) and Pre-mRNA processing factor 8 (PRPF8), and the secondary structure formed by the expanded CAG repeat in the mRNA, affecting the splicing of a range of transcripts.15,16 This interaction appears to be dependent on the purity of the CAG repeat (ie, the absence of CAA interruptions), as Mbnl1 was found to be recruited to nuclear foci in the novel BAC-CAG mouse model, which has an uninterrupted repeat, but not in the BACHD model, which harbors an interrupted repeat.17

Finally, the presence of the expanded CAG repeat has also been shown to induce repeat-associated non-AUG dependent (RAN) translation, which leads to the production of homopolymers other than polyQ that may also negatively impact cell function. RAN translation products have been detected in the affected brain regions of patients, as well as in N171-82Q mice and a C. elegans model.18,19 However, the actual contribution of RAN translation products to HD is not clear, as, for example, no RAN toxicity was observed in HD140Q knock-in mice.20

The expanded polyQ-containing mutant HTT (mHTT) protein has been shown to interact aberrantly with a variety of proteins, including transcriptional regulators such as RNA polymerase II subunit A (POLR2A), Tumor protein p53, Mouse double minute 2 (MDM2), CREB-binding protein (CBP) and Heat shock protein 70 (HSP70), cell cycle regulators like Ras homolog enriched in brain (Rheb) and mammalian target of rapamycin (mTOR), and cytoskeleton proteins such as actin and neurofilament light (NF-L). These aberrant interactions result in a complex and widespread molecular pathology, affecting many essential processes in the cell, including DNA damage repair, transcriptional regulation, mitochondrial function and apoptosis.2125 Importantly, premature polyadenylation of the pre-mRNA as well as proteolytic cleavage of HTT protein lead to the production of a variety of HTT fragments, and there is ample evidence that such fragments, especially the short N-terminal species, are more toxic than the full-length mHTT protein.2635 In order to make tailored therapeutics towards the short toxic fragments, a good understanding of the mechanisms leading to their formation is needed. In this review, we therefore focus on how toxic N-terminal HTT protein species are produced and how they are linked to toxicity, as well as on therapeutic strategies that are capable of reducing these fragments.

N-terminal HTT protein fragments are mainly produced through two distinct processes: proteolytic cleavage and premature polyadenylation (see Figure 2 and Table 1).

Table 1 Overview of Proteolytic Cleavage Sites

Figure 2 Schematic overview of production of N-terminal HTT protein. (A) Regular splicing, overview of the resulting mRNA and full-length protein and the identified proteolytic cleavage sites. (B) Alternative splicing and premature polyadenylation and resulting transcript. (C) Resulting protein species and propensity for nuclear entry, aggregation and toxicity.

The group of Michael Hayden first showed that HTT could be cleaved proteolytically by apopain (caspase-3) in a repeat-length dependent manner.36 This was confirmed in a follow-up study, in which they mapped one of the caspase-3 cleavage sites to D513 and another site C-terminally of amino acid (aa) 548. Furthermore, two caspase-1 cleavage sites were identified in the first 548 aa. In contrast to their previous work with truncated HTT, the authors found no repeat-length dependence of cleavage efficiency of full-length HTT.37 In a third study, the authors were able to map the second caspase-3 cleavage site to D552, and further identified a caspase-6 cleavage site at D586.38 More recently, Martin et al recently identified yet another caspase cleavage site at D572, which was shown to be cleaved by caspase-1 and caspase-2.39

Both full-length and N-terminal caspase-cleavage products of HTT were found to be substrates for cleavage by calpains.4042 Four calpain cleavage sites have been mapped, at aa 437, 465/469 and 536/54041 and between aa 63111,42 calpain cleavage efficiency appears to be positively correlated with repeat length.41,42 Furthermore, it was shown that calpain levels, and in particular the active form, were increased in the caudate of HD patients compared to controls.41

Next to caspase and calpain generated fragments, various other cleaved HTT products have been described. Lunkes et al identified two N-terminal HTT fragments, cp-A and cp-B, which appeared to be generated in transfected NG108 cells through cleavage by aspartic endopeptidases. The C-terminus of HTT cp-A fragment was mapped between aa 104114. N-terminal fragments with the same immunogenic properties were identified in nuclear inclusions in post mortem frontal cortex of HD patients.43

Similarly, Schilling et al identified an N-terminal fragment ending between aa 90115 in post mortem tissues from HD patients and N171-82Q mice, as well as in transfected HEK293 cells.44 Further investigation in a HEK293 cell model revealed that short, HTT cp-B-like fragments were efficiently processed to HTT cp-A-like fragments, while longer HTT fragments proved to be inefficient substrates. The C-terminus of the HTT cp-A-like fragments was mapped between aa 105 and 115124. Although similar in size to the fragment described by Lunkes et al, inhibition of aspartyl proteases did not affect the formation of the cp-A-like fragment, and the authors were unable to identify any protease that generates these HTT cp-A-like fragments, suggesting that i) the fragments are not the same or ii) that the cp-A-like fragment described by Schilling et al is the same fragment but generated by a novel protease, which may be cell-type dependent.45 Ratovitski et al identified two N-terminal fragments (HTT cp-1 and cp-2) in PC12 and HEK293 cells expressing full-length HTT with 21Q or 126153Q or a truncated N1212 HTT fragment with 15Q or 138Q.46 These fragments were similar in size to the previously described HTT cp-A and cp-B fragments but were not affected by inhibition of aspartic endopeptidases. In addition, they were not affected by deletion of aa 105114. In combination with the epitope mapping, this narrowed the C-terminus of the HTT cp-1 fragment down to between aa 90 and 105, shorter than the cp-A and cp-A-like fragments described by Lunkes et al43 and Schilling et al44,45 Based on the absence of identified proteases and on the fragment length, we speculate that the generation of these fragments could involve aberrant splicing (see Aberrant Splicing and Premature Polyadenylation), although this would require further investigation.

Finally, Landles et al showed fourteen different N-terminal HTT protein isoforms (fragments 114) in brain tissue from HdhQ150 KI mice, the three shortest of which (fragments 1214) were specific to mHTT.33 Some of these fragments could be linked to specific proteolytic cleavage events: fragment 7 terminated at a novel calpain cleavage site between aa 510654, fragment 8 appeared to correspond to the D586 caspase-6 cleavage product, fragment 9 was likely produced by cleavage at calpain site 536 and fragment 10 by caspase cleavage at D513. Lastly, fragment 13 was determined to correspond to HTT-ex1.

In summary, many different proteases have been found to act on mHTT and wtHTT, generating N-terminal and C-terminal HTT fragments. The availability of antibodies that can recognize these fragments, as well as the possibility to specifically inhibit certain proteases, have allowed mapping of various fragments, albeit with variable resolution. Nonetheless, for multiple fragments, the mechanisms of production remain to be identified.

Besides proteolytic cleavage, there are other mechanisms that lead to the generation of toxic N-terminal mHTT fragments. Sathasivam et al showed that incomplete splicing of intron 1 leads to the production of a short premature polyadenylated HTT-ex1 transcript in various HD mouse models and that this HTT-ex1 can be translated into a 90 aa N-terminal HTT-ex1 protein (based on 23Q). HTT-ex1 transcript was also found to be expressed in HD patient fibroblasts and cortex.47 In a follow-up study, Neueder et al confirmed that the HTT-ex1 transcript can be detected in patient-derived fibroblasts, as well as HD patient cerebellum, sensory motor cortex and hippocampus, with the highest expression levels measured in juvenile HD patient tissues.48 The HTT-ex1 transcript has also been detected by RNA-sequencing in various HD mouse models, including BACHD, BAC-CAG and HdhQ111.17 Both in vitro and in patient-derived tissues, the production of the HTT-ex1 transcript appears to be positively correlated with CAG repeat length, showing much higher expression in cells and tissues derived from juvenile HD patients.48,49

The current hypothesis is that HTT-ex1 formation is influenced by a combination of sequestration of spliceosome components such as U1 snRNP at the CAG repeat, leading to less efficient splicing of exon 1 to exon 2, and a reduced transcription rate, which leads to longer exposure of the cryptic polyA site in intron 1. Although the Bates group initially found evidence for the involvement of Serine and Arginine Rich Splicing Factor 6 (SRSF6) in HTT-ex1 formation,47,49 they later found that the silencing of Srsf6 in HD mouse models did not affect HTT-ex1 formation.50 It has therefore been hypothesized that multiple RNA-binding proteins may be involved in the missplicing of HTT-ex1.12 Regardless of the exact mechanisms involved, aberrant mHTT splicing is CAG repeat length dependent, suggesting that HTT-ex1 formation and associated toxicity would increase as somatic instability progresses in HD48 and that interventions targeting repeat expansion and HTT-ex1 may have therapeutic advantage.

Consistently accumulating evidence indicates that small N-terminal fragments containing extended polyQ tracts significantly contribute mHTT cellular mislocalization, aggregation and toxicity. Initial studies by the Ross group showed that transfection of N2a or HEK293 cells with full-length HTT with either 23Q or 82Q, or of truncated HTT N171-18Q or N63-18Q resulted in a diffuse cytoplasmic localization of the protein. In contrast, transfection with N171-82Q or N63-82Q led to more punctate labeling in both cytoplasm and nucleus, with the short N63-82Q construct showing the most prominent nuclear localization.51 The Hayden group found similar results, showing that N-terminal fragments of 427, 548 or more aa formed mainly perinuclear aggregates, while fragments up to 224 aa showed both cytoplasmic and nuclear aggregates. Furthermore, they found that pathogenicity depended both on repeat length and on fragment size.26,27

Barbaro et al found that, in Drosophila, shorter N-terminal fragments were more toxic and more prone to aggregate, with HTT-ex1 being by far the most toxic species.28 In mice, the R6/2 model that expresses only HTT-ex1 is by far the most swiftly progressing HD mouse model,52,53 while conditional suppression of HTT-ex1 has been shown to be neuroprotective.54 Recent in vitro studies by the Lashuel group confirm these results and further extend the findings by showing that the polyQ and Nt17 domains of HTT-ex1 synergistically modulate the aggregation propensity of HTT-ex1, with a key role of the Nt17 domain in regulating HTT-ex1 aggregation dynamics and subcellular localization and toxicity.34

There is conflicting evidence with regard to the pathogenicity of nuclear and cytoplasmic mHTT. Some groups have reported evidence that nuclear localization is required for toxicity. For example, the Greenberg group showed that adding a nuclear export signal to a N171 HTT fragment blocked its toxicity in transfected striatal neurons.55 In contrast, the Hayden group reported that neither the addition of a nuclear localization signal to a N548 HTT fragment nor the addition of a nuclear export signal to a N151 fragment altered the toxicity of those fragments, suggesting that both the nucleus and the cytoplasm are sites of HD toxicity.56 Trushina et al found that nuclear entry of mHTT only occurred after commitment of a cell to cell death. Therefore, the authors argue that nuclear mHTT localization may not be the primary event leading to toxicity.57

Intranuclear and neuropil aggregates have been observed in most HD animal models,17,30,31,5863 and the presence of aggregates containing N-terminal HTT fragments has also been confirmed in patient brains by multiple groups.40,64,65 However, various groups have shown that it is not the insoluble aggregates or inclusion bodies, but rather the soluble oligomers that are the more toxic species.6669 In fact, some groups have found evidence that the formation of intranuclear inclusions may be protective,55,70,71 as reviewed by Arrasate and Finkbeiner.72 Mechanistically, this may be explained by the fact that soluble mHTT-ex1 oligomers have more aberrant protein interactions than insoluble aggregates and inclusions.73 Importantly, the length of N-terminal protein species and the associated sequence context, as well as post-translational modifications, also appear to play an important role in the aggregation process.35,74,75 For more in-depth reviews on the role of post-translational modifications, we redirect elsewhere.76,77

Various approaches have been investigated to therapeutically lower the expression or reduce the toxicity of the mutant HTT protein. The proteolytic cleavage pathway can be targeted to reduce the formation of N-terminal mHTT protein species. Furthermore, the N-terminal part of the protein can be targeted to reduce aggregation and/or increase clearance of mHTT. Finally, mHTT can be targeted at the transcript or gene level. Here, we will focus on approaches that are able to target not only full-length HTT but also HTT-ex1 and other N-terminal mHTT species, considering their potential therapeutic advantage (see Table 2).

Table 2 Overview of Studies Targeting HTT Protein

Caspase inhibition has been shown to reduce the proteolytic cleavage of mHTT and to improve the HD phenotype in BACHD78 and HdhQ111 mice.79 These results are backed up by earlier studies, where mutation of caspase-6 cleavage sites slowed down disease progression in YAC128 mice.80 However, it is not clear to what extent the protective effects are due specifically to the reduction of N-terminal mHTT species, rather than a general protective effect of caspase inhibition, as caspase inhibition was also protective in R6/2 and malonate models of HD, which do not express caspase-cleavable mHTT.8183

Using a different approach, Evers et al showed that removal of the caspase-6 cleavage site by antisense oligonucleotide (ASO)-mediated skipping of (part of) exon 12 led to reduced levels of the N568 fragment in vitro and in vivo in wild type and YAC128 mice.84,85 Except for the absence of astrogliosis, no data are available regarding phenotypic effects of this ASO treatment.

None of these approaches have yet successfully been translated into the clinic, and although all may potentially decrease the formation of toxic mHTT fragments and have the potential of allele-specificity, mechanisms of RNA-associated toxicity would not be addressed.

Aptamers are single-stranded oligonucleotides that, through their tertiary structure, can interact with target molecules such as proteins. The Roy lab identified aptamers that bind specifically to mHTT with 51 or 103Q but not wtHTT with 20Q.86,87 The selected aptamers were shown to inhibit aggregation of recombinant mHTT-ex1 in cell-free assays and in yeast, as well as reducing oxidative stress and mitochondrial dysfunction.86 To our knowledge, this approach has not yet been tested in vivo.

Various antibodies have been expressed intracellularly as intrabodies to target the N-terminus of HTT. In vivo, such intrabodies are delivered using viral vectors. An excellent review on the use of intrabodies in various neurodegenerative diseases was written by Messer and Butler.88

Two groups of intrabodies have been tested most extensively (see Figure 3): those that bind to the N-terminus of HTT (VL12.3, scFv-C4) and those that recognize the proline-rich regions (PRRs) in HTT-ex1 (MW7, Happ1, Happ3, INT41). In addition, there is some literature about polyQ-binding intrabodies (MW1, MW2) and a more C-terminal intrabody derived from EM48 (scFv-EM48).

Figure 3 Anti-HTT Exon 1 intrabodies. (A) Antigens used to select the published anti-HTT intrabodies. (B) Specific binding identified by crystallography for scFvC4 and VL12.3.

Notes: Reproduced from Messer A, Butler DC. Optimizing intracellular antibodies (intrabodies/nanobodies) to treat neurodegenerative disorders. Neurobiol Dis. 2020;134(October 2019):104619. doi: 10.1016/j.nbd.2019.104619 under Creative Commons BY-NC-ND 4.0.88

Southwell et al showed that intrabodies that bind to the PRR, ie, MW7, Happ1 and Happ3, increase the turnover of mHTT-ex1 overexpressed in vitro. VL12.3, an intrabody that binds to the N-terminal 17 aa of HTT, did not affect turnover, but did increase the nuclear localization of mHTT-ex1.90 In vivo, the PRR-binding Happ1 was shown to be beneficial in five different HD mouse models. In contrast, VL12.3, while effective in a lentiviral HD model, was ineffective in YAC128 mice and had a detrimental effect in R6/2 mice.91 The authors later showed that the increased turnover mediated by the PRR-binding intrabodies is dependent on a calpain-chaperone-mediated autophagy-dependent mechanism and that this process is blocked by VL12.3,92 explaining the detrimental effects of VL12.3.

Although scFv-C4 also binds to the N-terminus of HTT,93 its predominant cytoplasmic localization appears to protect from the detrimental effects observed for VL12.3.89 The scFv-C4 intrabody was shown to have beneficial effects in various HD models, including in vitro models, Drosophila and different mouse models.9498

Two additional intrabodies have been investigated: scFv-EM48 and INT41. Like Happ1, scFv-EM48, which binds just C-terminally to the second PRR, was shown to increase turnover of mHTT, and improved motor function of N171-82Q mice.99 INT41, an intrabody that recognizes the same epitope as Happ1, but which has enhanced cytoplasmic solubility, was shown to improve cognitive function in female R6/2 mice.100

In addition to the increased turnover induced by some of the intrabodies, the endogenous cellular machinery can be harnessed specifically to target proteins for degradation, using engineered proteins, peptides or small molecules. These can direct the protein of interest to the ubiquitin proteasome system, the autophagy-lysosomal pathway or chaperone-mediated autophagy. These approaches and their specific application in the context of HD have been extensively reviewed by Jarosiska and Rdiger.101

Two such approaches specifically target the polyQ region. Bauer et al engineered a fusion molecule consisting of two copies of a polyQ-binding peptide (QBP1) and heat shock-cognate protein 70 (HSC70)-binding motifs to induce chaperone-mediated autophagy.102 Clift et al co-expressed a polyQ-binding antibody (3B5H10) with TRIM21 in an approach that they call Trim-Away, to target mHTT for proteasomal degradation.103 Additionally, Butler et al produced a fusion protein consisting of the scFv-C4 intrabody and a PEST motif to enhance proteasomal degradation of HTT-ex1.104

Several endogenous proteins have been described to enhance the turnover of mHTT, including Praja1 ubiquitin ligase,105 TBK1106 and Blm10/PA200.107 Induction or overexpression of such proteins may represent a therapeutic strategy, although, so far, this notion is only supported by experiments in cellular, Drosophila, and C. elegans models. Additionally, specificity for mHTT has not been shown for any of these three proteins.

Finally, a small molecule that can bind to mHTT-ex1, called GLYN122, has been identified recently. GLYN122 was shown to reduce mHTT-ex1 aggregation in PC12 cells, as well as reducing mHTT in cortex and striatum of R6/2 mice after intraperitoneal injection.108

Next to targeting the pathogenic protein species itself, the production of such proteins can also be inhibited by targeting the HTT mRNA. Many different approaches have been tested to this effect, including ASOs, siRNAs, shRNAs and miRNAs (Table 3). Again, we only focus on those strategies that target HTT-ex1. Broadly speaking, the HTT-ex1 mRNA targeting approaches can be divided into those that target the expanded CAG repeat, and those that target other regions of HTT-ex1. In addition, some other approaches have been described.

Table 3 Overview of Studies That Evaluated Therapeutic Approaches Targeting HTT at the RNA Level

Many studies have tested ASOs or RNAi agents to target the CAG repeat.109122 In general, CAG-targeting confers preference towards the expanded allele, as this allows for binding of multiple molecules per mRNA.111 Only a few studies included in vivo efficacy. Yu et al showed the efficacy of their siRNA in HdhQ150 mice.115 Monteys et al used transgenic mice expressing tagged full-length wtHTT and mHTT, showing preferential silencing of mHTT.118 Datson et al showed the efficacy of their CAG-targeting ASO in R6/2 and Q175 mice,120 an ASO that is now further developed by Vico Therapeutics. Kotowska-Zimmer et al have shown that artificial miRNAs targeting the CAG repeat specifically reduced mHTT in YAC128 mice.122

A number of strategies that target other regions of HTT-ex1 have been described as well.123137 This approach would be expected to lower both wtHTT and mHTT. With the exception of Boado et al and Kordasiewicz et al, who used ASOs, all of these studies utilized RNAi agents. Various groups have demonstrated efficacy of siRNA or shRNA in R6/1, R6/2 and AAV100Q mice.127130 uniQures miRNA therapy has shown target engagement in the widest range of HD animal models, including Hu128/21, Q175 and R6/2 mice, lentiviral rat model and transgenic HD minipigs,123,124,132134,136 as well as a favorable safety profile in toxicity studies in rats and non-human primates.137

A handful of studies described other approaches to HTT RNA-targeting. Rindt et al developed a method to induce trans-splicing, by which mHTT exon 1 is replaced with exogenous wtHTT exon 1 in the mRNA. Thus far, there is only in vitro proof of principle for this approach, and the efficiency is rather low, with 1015% of trans-splicing observed even after extensive optimization.138,139 Batra et al have developed an RNA-targeting Cas9 approach which targets the CAG repeat.140 For HD, there is only in vitro evidence for this approach so far, but a similar approach targeting a CUG (cytosine, uracil, and guanine) repeat was shown to be effective in vivo in myotonic dystrophy type 1 mouse models.141 This platform is being developed by Locanabio.

Finally, some small molecules have been described to bind to either HTT-ex1 or the CAG repeat, most notably furamidine, myricetin and a series of pyridocoumarin derivatives, reviewed elsewhere.12 These compounds have been described to inhibit translation of HTT. However, specificity of such compounds is generally low, thereby increasing the chance of unwanted off-target effects.

Finally, several approaches that target the HTT gene have been described (Table 4).

Table 4 Overview of Studies Targeting the HTT Gene

Transcription can be prevented using zinc finger proteins (ZFPs) targeting the expanded CAG repeat.142144 This approach shows allele-selectivity for the expanded repeat and is currently being developed for the clinic by Sangamo and Takeda. Further, CRISPR-Cas9 genome editing approaches have been developed to either knock out HTT by inducing mutations or excise the region containing the CAG repeat. Several groups have shown in vitro and in vivo proof of principle using single guide RNAs directed to HTT-ex1 to induce HTT knockout.145148 Further, using a double guide RNA approach, various groups have shown that it is possible to excise the region containing CAG repeat.149154 The size of this region differs based on the chosen guide RNAs, with the first report by Shin et al deleting a large 44 kb region,149 while the most precise excision was shown by Yang et al and Monteys et al, who deleted only the CAG repeat and small flanking regions.150,151

Several HTT lowering therapies are either already in clinical trials or are close to entering the clinic. These therapies include different therapeutic modalities and mechanisms of action, each with distinct potential efficacy and safety profiles. Only the approaches in clinical trials or performing IND-enabling studies are covered here.

Two of the most advanced programs, the Phase III trial with the non-allele-specific HTT exon 36-targeting ASO tominersen (Roche) and the phase I/II trials with the allele-specific mHTT-associated single nucleotide polymorphism (SNP)-targeting ASOs WVE-120101 and WVE-120102 (Wave Life Sciences) were halted in 2021, as reviewed elsewhere.155 Roche plans to design a new Phase II study with tominersen, for younger adult patients with lower disease burden (https://ir.ionispharma.com/news-releases/news-release-details/ionis-partner-evaluate-tominersen-huntingtons-disease-new-phase). Wave Life Sciences has now initiated a new trial with their novel product WVE-003, which targets another SNP and has improved chemistry (clinicaltrials.gov NCT05032196). These ASOs are administered repeatedly through intrathecal administration, which may explain some of the adverse events observed with tominersen, which was more pronounced in the cohort receiving more frequent administration.155 Neither drug is expected to affect HTT-ex1 formation or RNA-mediated toxicity.

Novartis and PTC Therapeutics both have initiated Phase 2 clinical trials for their splicing modulators Branaplam (NCT05111249) and PTC518 (NCT05358717). These small molecules induce the inclusion of a pseudoexon between HTT exons 49 and 50, which leads to a premature stop codon and subsequent nonsense-mediated decay.156,157 One of the main advantages is that these small molecules can be administered orally. Furthermore, the mechanism of action targets the pre-mRNA and is therefore quite upstream in the molecular pathology. However, this approach is not specific for the mutant allele and, as it targets a downstream exon, is also not expected to affect HTT-ex1 production or toxic RNA gain-of-function.

In a more indirect fashion, metformin has been shown to reduce translation of HTT through interacting with the MID1/PP2A/mTOR protein complex.158 Interestingly, the effect of metformin was found to be specific for mHTT and to also impact HTT-ex1 protein formation. The drug can be administered orally, and as it is already in clinical use for the treatment of diabetes, its safety profile has already been well established. Metformin is currently being tested for the treatment of HD in a phase III clinical trial to establish its potential as a treatment for HD (NCT04826692). Although it has been shown to reduce HTT levels, RNA-mediated toxicity is not expected to be targeted by its mechanism of action.

There are no therapies that target HTT-ex1 exclusively, but some therapies target HTT-ex1 in addition to the full-length HTT. The most advanced is uniQures gene therapy AMT-130, which is currently being tested in phase I/II clinical trials (NCT04120493 and NCT05243017). AMT-130 is an AAV5-delivered miRNA which is administered through a one-time intrastriatal injection. This therapy is not allele-selective, and its effect on RNA-mediated toxicity has not yet been established.

Several other HTT-ex1 targeting candidates are close to entering clinical trials, including Galyan Bios HTT-ex1 binding small molecule GLYN122 and Vybions INT41 intrabody. These therapeutic candidates target the protein and are therefore not expected to impact RNA-mediated toxicity. According to the companies websites, both are performing IND-enabling studies, although their target date to enter the clinic is not clear (https://www.galyan.bio/pipeline, https://www.vybion.com/?page=product_pipeline).

Likewise, Vico Therapeutics received FDA orphan drug designation for their CAG-targeting ASO in July 2021 and is expected to start clinical trials soon (https://vicotx.com/pipeline/). Takeda and Sangamo are further developing their ZFP approach targeting the CAG repeat (https://www.sangamo.com/programs/). Both approaches preferentially target mHTT and as they act on the (pre-)mRNA and on transcription, respectively, these drug candidates may also have a beneficial effect on RNA-mediated toxicity.

Although all the approaches mentioned, as well as others in earlier phases of development, aim to reduce HTT levels, their mechanism of action is different and not all pathways related to HTT toxicity will be engaged. The relative contribution of each pathway is a matter of debate and is likely to depend on many factors, including age, tissue and cell type. Several of the described mechanisms of N-terminal HTT fragment production, including calpain cleavage and premature polyadenylation, have been shown to correlate with repeat length. This is also the case with HTT-ex1 formation through aberrant splicing. Therefore, it may be expected that as the repeat gets longer over time due to somatic instability, the contribution of these mechanisms will increase. Nonetheless, the broad molecular pathology of HD would likely benefit most from an intervention that acts as far upstream as possible, ie, on the DNA or the RNA level.

For an approach to be successful in disease modification, next to efficiency, adequate safety is key. Safety issues can arise from intrinsic characteristics of the therapeutic modality itself (eg, chemistry, properties of the therapeutic vector, and need of chronic administration), which are not covered in this review. The mechanism of action of the approach can also have different safety risks. Very specific approaches, with a well-understood mechanism, and with low to no interactions with other processes and molecules other than those related to HTT toxicity, would be preferred.

Multiple different approaches are running head-to-head. The small molecule splicing modulators are among the most elegant in terms of delivery, as these are capable of crossing the bloodbrain barrier and can therefore be administered orally. However, these small molecules are not specific for mHTT or even solely for HTT, and long-term studies are needed to determine the safety profile. Furthermore, these splicing modulators are expected to affect neither aberrant splicing of HTT-ex1 nor toxic RNA gain-of-function effects. ASOs and siRNAs have a less favorable distribution and need to be administered locally, although novel chemistries, such as peptide nucleic acids and di-siRNAs, have shown more promising biodistribution and may allow for systemic administration. These synthetic oligonucleotides are active for a limited amount of time, and therefore need to be readministered frequently. CAG-targeting ASOs are expected to not only reduce HTT and HTT-ex1 protein gain-of-function but also to alleviate RNA-mediated toxicity; however, non-specific effects on other genes containing CAG repeats may be difficult to overcome. Finally, the gene therapy approaches utilize AAVs to deliver their cargo. The current generation of AAVs is not sufficiently capable of crossing the bloodbrain barrier and therefore still needs to be administered locally, although efforts are ongoing to identify novel capsids that could be administered in a less invasive manner, eg, Goertsen et al.159 Because most cells that are targeted in HD are non-dividing, a more invasive route of administration is, however, less of an issue, as the therapy would only need to be administered once. uniQures miRNA-based strategy would reduce toxic protein gain-of-function, whereas Takeda and Sangamos ZFP approach targets DNA and thereby acts upstream of mHTT transcription, which would improve both toxic protein- and RNA gain-of-function; yet, as the mechanism of action of this approach involves direct targeting of the repeat, off-target effects may be an issue. Pre-clinically, gene editing approaches using CRISPR-Cas are being explored. However, long-term studies will need to show the safety profiles of such approaches.

To maximize therapeutic efficacy, future research will need to point out whether it may be advantageous to combine various therapeutic strategies with different modes of action. Further, it is likely that any therapeutic approach will benefit from as early intervention as possible. To this end, excellent safety profiles and good biomarkers of both safety and efficacy will be key.160

In summary, we have reviewed the production of N-terminal HTT protein fragments, their role in HD pathology, as well as therapeutic approaches to target these toxic species. Extensive research into HD continues to deepen our understanding of the broad molecular mechanisms leading to disease. With the increasing understanding of the pathological mechanisms associated with mHTT, several different therapeutic approaches are being developed, which will hopefully lead, in the near future, to halting or modification of this devastating disease.

We thank our uniQure colleagues who provided a critical review of the manuscript.

All authors made a significant contribution to the work reported, whether that is in the conception, study design, execution, acquisition of data, analysis and interpretation, or in all these areas; took part in drafting, revising or critically reviewing the article; gave final approval of the version to be published; have agreed on the journal to which the article has been submitted; and agree to be accountable for all aspects of the work.

LB, ME and AV are employees of, and may own stock/options in, uniQure biopharma B.V. In addition, Dr Astrid Valls has a patent WO2021053018 issued to UNIQURE IP B.V. The authors report no other conflicts of interest in this work.

1. Crowell V, Houghton R, Tomar A, Fernandes T, Squitieri F. Modeling manifest Huntingtons disease prevalence using diagnosed incidence and survival time. Neuroepidemiology. 2021;55(5):361368. doi:10.1159/000516767

2. Rawlins MD, Wexler NS, Wexler AR, et al. The prevalence of Huntingtons disease. Neuroepidemiology. 2016;46(2):144153. doi:10.1159/000443738

3. Caron NS, Wright GE, Hayden MR, et al. Huntington disease. In: Adam M, Ardinger H, editors. GeneReviews. Seattle: University of Washington; 1993:134.

4. Wright GEB, Collins JA, Kay C, et al. Length of uninterrupted CAG, independent of polyglutamine size, results in increased somatic instability, hastening onset of Huntington disease. Am J Hum Genet. 2019;104(6):11161126. doi:10.1016/j.ajhg.2019.04.007

5. Lee J-M, Correia K, Loupe J; GeM-HD GM of HDC. CAG repeat not polyglutamine length determines timing of Huntingtons disease onset. Cell. 2019;178(4):887900.e14. doi:10.1016/j.cell.2019.06.036

6. Iyer RR, Pluciennik A, Mismatch DNA. Repair and its role in Huntingtons disease. J Huntingtons Dis. 2021;10(1):7594. doi:10.3233/JHD-200438

7. Schulte J, Littleton JT. The biological function of the Huntingtin protein and its relevance to Huntingtons disease pathology. Curr Trends Neurol. 2011;5:6578.

8. Liu JP, Zeitlin SO. Is huntingtin dispensable in the adult brain? J Huntingtons Dis. 2017;6(1):117. doi:10.3233/JHD-170235

9. Saudou F, Humbert S. The biology of Huntingtin. Neuron. 2016;89(5):910926. doi:10.1016/j.neuron.2016.02.003

10. Kaemmerer WF, Grondin RC. The effects of Huntingtin-lowering: what do we know so far? Degener Neurol Neuromuscul Dis. 2019;9:317. doi:10.2147/DNND.S163808

11. Neueder A, Bates GP. RNA related pathology in Huntingtons disease. Polyglutamine Disord. 2018;2018:85101. doi:10.1007/978-3-319-71779-1_4

12. Heinz A, Nabariya DK, Krauss S. Huntingtin and its role in mechanisms of RNA-mediated toxicity. Toxins. 2021;13(7):487. doi:10.3390/toxins13070487

13. Malik I, Kelley CP, Wang ET, Todd PK. Molecular mechanisms underlying nucleotide repeat expansion disorders. Nat Rev Mol Cell Biol. 2021;22(9):589607. doi:10.1038/s41580-021-00382-6

14. Sun X, Li PP, Zhu S, et al. Nuclear retention of full-length HTT RNA is mediated by splicing factors MBNL1 and U2AF65. Sci Rep. 2015;5:116. doi:10.1038/srep12521

15. Mykowska A, Sobczak K, Wojciechowska M, Kozlowski P, Krzyzosiak WJ. CAG repeats mimic CUG repeats in the misregulation of alternative splicing. Nucleic Acids Res. 2011;39(20):89388951. doi:10.1093/nar/gkr608

16. Schilling J, Broemer M, Atanassov I, et al. Deregulated splicing is a major mechanism of RNA-induced toxicity in Huntingtons disease. J Mol Biol. 2019;431(9):18691877. doi:10.1016/j.jmb.2019.01.034

17. Gu X, Richman J, Langfelder P, et al. Uninterrupted CAG repeat drives striatum-selective transcriptionopathy and nuclear pathogenesis in human Huntingtin BAC mice. Neuron. 2022;110(7):11731192.e7. doi:10.1016/j.neuron.2022.01.006

18. Baez-Coronel M, Ayhan F, Tarabochia AD, et al. RAN translation in Huntington disease. Neuron. 2015;88(4):667677. doi:10.1016/j.neuron.2015.10.038

19. Rudich P, Watkins S, Lamitina T. PolyQ-independent toxicity associated with novel translational products from CAG repeat expansions. PLoS One. 2020;15(4):121. doi:10.1371/journal.pone.0227464

20. Yang S, Yang H, Huang L, et al. Lack of RAN-mediated toxicity in Huntingtons disease knock-in mice. Proc Natl Acad Sci U S A. 2020;117(8):44114417. doi:10.1073/pnas.1919197117

21. Steffan JS, Kazantsev A, Spasic-Boskovic O, et al. The Huntingtons disease protein interacts with p53 and CREB-binding protein and represses transcription. Proc Natl Acad Sci U S A. 2000;97(12):67636768. doi:10.1073/pnas.100110097

22. Suhr ST, Senut MC, Whitelegge JP, Faull KF, Cuizon DB, Gage FH. Identities of sequestered proteins in aggregates from cells with induced polyglutamine expression. J Cell Biol. 2001;153(2):283294. doi:10.1083/jcb.153.2.283

23. Bae B, Xu H, Igarashi S, et al. p53 mediates cellular dysfunction and behavioral abnormalities in Huntingtons disease. Neuron. 2005;47(1):2941. doi:10.1016/j.neuron.2005.06.005

24. Pryor WM, Biagioli M, Shahani N, et al. Huntingtin promotes mTORC1 signaling in the pathogenesis of Huntingtons disease. Sci Signal. 2014;7(349):113. doi:10.1126/scisignal.2005633

25. Gao R, Chakraborty A, Geater C, et al. Mutant Huntingtin impairs PNKP and ATXN3, disrupting DNA repair and transcription. Elife. 2019;8:131. doi:10.7554/eLife.42988

26. Martindale D, Hackam A, Wieczorek A, et al. Length of Huntingtin and its polyglutamine tract influences localization and frequency of intracellular aggregates. Nat Genet. 1998;18(2):150154. doi:10.1038/ng0298-150

27. Hackam AS, Singaraja R, Wellington CL, et al. The influence of Huntingtin protein size on nuclear localization and cellular toxicity. J Cell Biol. 1998;141(5):10971105. doi:10.1083/jcb.141.5.1097

28. Barbaro BA, Lukacsovich T, Agrawal N, et al. Comparative study of naturally occurring Huntingtin fragments in Drosophila points to exon 1 as the most pathogenic species in Huntingtons disease. Hum Mol Genet. 2015;24(4):913925. doi:10.1093/hmg/ddu504

29. ElDaher M, Hangen E, Bruyre J, et al. Huntingtin proteolysis releases nonpolyQ fragments that cause toxicity through dynamin 1 dysregulation. EMBO J. 2015;34(17):22552271. doi:10.15252/embj.201490808

30. Mangiarini L, Sathasivam K, Seller M, et al. Exon 1 of the HD gene with an expanded CAG repeat is sufficient to cause a progressive neurological phenotype in transgenic mice. Cell. 1996;87(3):493506. doi:10.1016/S0092-8674(00)81369-0

31. Schilling G, Becher MW, Sharp AH, et al. Intranuclear inclusions and neuritic aggregates in transgenic mice expressing a mutant N-terminal fragment of Huntingtin. Hum Mol Genet. 1999;8(3):397407. doi:10.1093/hmg/8.3.397

32. Tanaka Y, Igarashi S, Nakamura M, et al. Progressive phenotype and nuclear accumulation of an amino-terminal cleavage fragment in a transgenic mouse model with inducible expression of full-length mutant Huntingtin. Neurobiol Dis. 2006;21(2):381391. doi:10.1016/j.nbd.2005.07.014

33. Landles C, Sathasivam K, Weiss A, et al. Proteolysis of mutant Huntingtin produces an exon 1 fragment that accumulates as an aggregated protein in neuronal nuclei in Huntington disease. J Biol Chem. 2010;285(12):88088823. doi:10.1074/jbc.M109.075028

34. Vieweg S, Mahul-Mellier AL, Ruggeri FS, et al. The Nt17 domain and its helical conformation regulate the aggregation, cellular properties and neurotoxicity of mutant Huntingtin exon 1. J Mol Biol. 2021;433(21):167222. doi:10.1016/j.jmb.2021.167222

35. Chongtham A, Bornemann DJ, Barbaro BA, et al. Effects of flanking sequences and cellular context on subcellular behavior and pathology of mutant HTT. Hum Mol Genet. 2020;29(4):674688. doi:10.1093/hmg/ddaa001

Visit link:
Emerging Therapies for Huntington's Disease Focus on N-T | BTT - Dove Medical Press

Duchenne muscular dystrophy (DMD) was first described by the French neurologist Guillaume Benjamin Amand Duchenne in the 1860s, though it took until 1986 for researchers to identify a particular gene flaw that leads to the condition. The identification of the dystrophin gene by Louis Kunkel and Jerry Louis opened the door for disease-modifying therapies such as exon-skipping, stop codon readthrough, gene therapy, and CRISPR/cas9 mediated gene editing that focus in on dystrophin restoration.

Currently, there are 4 drugs approved in the United States for mutations amenable to skipping of exons 51, 53, and 45, which are applicable to about 30% of patients total with DMD. Each of these were approved through the accelerated approval pathway, which provides for the approval of drugs that treat serious or life-threatening diseases. At the recently concluded 2022 American Association of Neuromuscular & Electrodiagnostic Medicine (AANEM) annual meeting, September 21-24, in Nashville, Tennessee, Emma Ciafaloni, MD, gave the Reiner Lecture to a crowd of a few hundred clinicians, highlighting new treatments for DMD.

In her talk, she summarized the expanding pipeline of agents for DMD, how each differs mechanistically, and whether any are more advantageous than another. Ciafaloni, a professor of neurology and pediatrics at the University of Rochester Medical Center, also discussed how to translate new treatments from trials to clinics, the need to improve clinical trial design and process, and how researchers can build on previous successes. Prior to her presentation, as part of a new NeuroVoices, Ciafaloni provided commentary on several topics regarding the DMD pipeline, including the differences and advantages each approach brings, as well as ways to overcome complexities with conducting clinical trials.

Emma Ciafaloni, MD: The exciting research development in the field of Duchenne muscular dystrophy is extraordinary. Many years after understanding the pathophysiology of Duchennewhich the gene wasnt discovered until the late 1980sall that knowledge is finally paying off and opening a window on therapeutic strategies that have to do with disease-modifying gene editing. There are many different approaches now, some like exon skipping, which are already used in the clinics. Some are different stages of development, such as gene therapy in phase three trials. I would be surprised if we didnt have a gene therapy drug in the clinic in the near future. And then CRISPR, which has not been used yet in humans, but has made major milestones and proof of concept in animal models that are highly promising. These are all strategies that are advancing very rapidly, I think that the field is moving much faster than in the past because of the collaboration between pharma and academia, and the patients and the families. There are many clinical trials in Duchenne, and it's a very exciting time.

Also, there has never been a time before in muscular dystrophies in general, not just Duchenne, where there were so many different, new ideas, as well as old ideas that finally started working in humans. The second part of my talk briefly covered other treatments, ideas and strategies that are not directed to restoration of dystrophin. They're not genetic treatments, but they work more on the downstream pathology of muscle degeneration into Duchenne, like the fibrosis, inflammation, and regeneration. There are some interesting drugs out there, probably a few that are going to be approved soon. We're looking at probably a multifactorial type of treatment, it may be a combination treatment. It's never been a richer time in terms of treatments for Duchenne. Also, it's exciting because some of the lessons learn, for example, with the genetic treatments, are extremely helpful for the larger field of neuromuscular diseases and even neurology. The learning has been fantastic.

With spinal muscular atrophy leading the way, we're moving into more muscle-based diseases [with gene therapy], but the lessons learned are still very valuable. Additionally, we have seen this collaboration between different sponsors, pharmaceuticals, and academias to share the learning, because that's just going to help move things faster and better and in a safer way. That is a positive phenomenon that is unprecedented, and it's helping to accelerate the science in a safe and effective way.

There are still many questions that remain. All these genetic modification approaches have been exon skipping, or gene therapy replacement. They don't replace the full-length dystrophin because it's a very large gene. It's a biologically modified type of dystrophin, so there is no doubt that it will have a profound benefit, but I think that there is plenty of room for improvement. Obviously, gene therapy is not approved yet, so remains to be seen in terms of clinical improvement. But even in the exon skipping, I think that we're going to see much more exciting next generation, exon-skipping that people are currently working on very hard on. The field of science and medicine always evolves. What we have now is only going to be much better down the road in a few years. I have no doubt, and the community of Duchenne is working very hard to make even the drugs that we have now, better.

Sometimes, for the more general neurologist or certainly for the general public, it's important to remember that when we talk about Duchenne muscular dystrophy, or many of our neuromuscular diseases that we discuss here at AANEM, these are also rare diseases. The definition from the FDA for a rare disease is less than 200,000 total patients in the United States. For Duchenne, for example, we're talking about maybe around 12,000 patients. This is not [multiple sclerosis], or Parkinson disease or Alzheimer disease. There are challenges in clinical trial designs that are unique, and they need to be understood. Some of the accelerated approval for some of these drugs is part of that challenge and difference. For example, especially with the genetic approach, some of these genetic approaches like exon skipping, only target a specific mutation in maybe 10% to 13% of patients. Now you're taking a subgroup of an ultra-rare disease that is only 10% of that population. Then you need to run clinical trials that are going to have a chance to prove a difference, and so, you restrict the inclusion criteria to a specific age. Then you're really challenged to find enough patients to do well in a placebo-controlled trial. It's important to keep that in mind that there is plenty of room for improvement in making our rare disease clinical trial design more effective, less time consuming for patients, and improving the approval path.

I also want to say that in Duchenne, the amount of data that has been produced in the past several years in terms of motor endpoints, natural history, the six-minute walk test, the North Star [Ambulatory Assessment], etc. These outcome measure prospective cohorts have been incredibly invaluable. This is just to recognize the incredible amount of work that researchers and families and patients have done in the past several years that is helping the field immensely. We are at a different time, its an exhilarating, exciting time. I think that the community of rare diseases like Duchenne have been incredibly, hard-working in a good, cohesive way to advance the field forward, which is very refreshing.

Transcript edited for clarity. Click here for more NeuroVoices.

Go here to read the rest:
NeuroVoices: Emma Ciafaloni, MD, on the Vast Expansion of Innovative Approaches to Duchenne Muscular Dystrophy - Neurology Live

To much applause and aplomb, MemorialCare Saddleback Medical Center broke ground last week for a new womens health facility a stones throw from the Laguna Woods Gate 2.

The 40,000-square-foot Womens Health Pavilion is under construction at the Laguna Hills medical center and is expected to be completed in 2023.

Our vision for the Womens Health Pavilion is to provide a truly innovative and holistic approach to womens health care, said Marcia Manker, CEO of MemorialCare Saddleback Medical Center. With the groundbreaking, this vision is coming to fruition and celebrates the lives and well-being of women of every age and from all walks of life.

The new facility will not only provide medical care to treat a condition or disease; it will provide care for the entire woman, including overall wellness and mental health, from birth to adulthood, Manker said.

At the groundbreaking for MemorialCare Saddleback Medical Centers new Womens Health Pavilion in Laguna Hills are, from left, Sarah Nederlander, Taylor Nederlander, Christy Ward, Assemblywoman Laurie Davies, Marcia Manker, Dr. Gary Levine, Supervisor Lisa Bartlett, Catherine Han, Heather Chu and Catherine Shitara.(Photo by Daniella Walsh)

MemorialCare Saddleback Medical Centers new Womens Health Pavilion will feature an airy lobby, adding to a comfortable environment, hospital officials say.(Courtesy of MemorialCare)

A rendering shows a treatment room in the Womens Health Pavilion under construction at the MemorialCare Saddleback Medical Center in Laguna Hills.(Courtesy of MemorialCare)

Sisters Taylor and Sarah Nederlander donated $2.5 million for the new Womens Health Pavilion in Laguna Hills through the Harry J. Nederlander Foundation.(Photo by Daniella Walsh)

Marcia Manker, MemorialCare Saddleback CEO(Courtesy of MemorialCare)

Dr. Gary Levine, director of MemorialCare breast centers.(Sally Aristei Photographs)

Heather Chu of Irvine is a cancer survivor who was treated at the MemorialCare Breast Center.(Photo by Daniella Walsh)

A rendering shows MemorialCare Saddleback Medical Centers new Womens Health Pavilion planned at the Laguna Hills medical center. It is expected to be completed in 2023. (Courtesy of MemorialCare)

The pavilion will house the already established MemorialCare Breast Center, which will be reconfigured into Orange Countys first comprehensive breast care center, with breast oncologists, reconstructive surgeons and state-of-the-art technology, all on the first floor of the new three-story building.

The facility will also provide maternity services in conjunction with Saddleback Womens Hospital, as well as medical personnel dedicated to sexual health and mental health. Cardiovascular health services are in the planning stages.

For older patients, the pavilion will have an osteoporosis clinic and a pelvic floor rehabilitation clinic staffed by specialized physical therapists. Pelvic floor issues affect more than 40% of women ages 60 to 79 and 50% of women 80 or older, Manker said.

With services all under one roof, women will have shorter wait times, officials said, even same-day appointments and expedited screening results to facilitate early detection and treatment plans for breast cancer. In addition, the center will have a retail shop focused on the needs of cancer patients, with wigs and other items to help them achieve a sense of their pre-cancer selves.

(Altogether, MemorialCare has nine breast care centers between Long Beach and Rancho Mission Viejo, all under the medical direction of Dr. Gary Levine, a breast cancer specialist with more than 25 years of experience, who has been involved in the planning of the new center for the past seven years.)

The new facility is focused on the future and the growing number of older women, Levine said.

By 2040, more than 20% of the population is projected to be over age 65, and the majority of older people are women, he said. Preventive care is paramount and should include activities for daily living, weight-bearing exercise as well as social engagement. The recent proliferation of retirement communities where older women can stay engaged and active leads to better health and longer life.

Also planned is a community education center that will include hosting of support groups, nutritional counseling and wellness classes such as yoga and Pilates for women of all ages. A verdant garden to soothe the senses is also in the masterplan.

Joining Manker at the groundbreaking Sept. 20 were Levine; Assembly Member Laurie Davies; Orange County Supervisor Lisa Bartlett; Christy Ward, president of the Saddleback Medical Center Foundation; and Dr. Catherine Han, foundation board chair, along with young philanthropists Taylor and Sarah Nederlander and cancer survivor Heather Chu.

Chu, 42, an Irvine resident, spoke about her experience at the MemorialCare Breast Center when she received a diagnosis of DCIS (ductal carcinoma in situ) breast cancer in January 2021. She ultimately had a double-mastectomy and reconstructive surgery.

It is difficult to talk about my experience in public, but I want to share to empower other women, Chu said. Cancer patients are faced with who to ask, where to go. It stood out to me how kind, knowledgeable and compassionate all the personnel were here.

Her treatment included genetic counseling and physical therapy, with Levine overseeing radiology and ultrasounds. She was later diagnosed with uterine cancer and had a hysterectomy.

MemorialCare helped me navigate that journey. Every single person I met was warm and welcoming, Chu recalled, quoting her nurse navigator as saying: Youre going to be OK; you got this; we are going to be here for you. I am going to hold you and not let you go and I will help you through this.

Chu added: There is a huge need for such a facility. As a wife and mother, mine was a terrifying experience. I love my cancer-free body. Cancer took my body but not my sense of self.

The new building was designed by c/a Architects, a Long Beach firm specializing in health care facilities.

Construction costs, along with the land, are around $80 million, Manker said.

Philanthropic contributions, including $2.5 million from sisters Sarah and Taylor Nederlander of the Harry J. Nederlander Foundation, help finance the project. Hence, the pavilions breast center will be named the Sarah & Taylor Nederlander Breast Center. Granddaughters of theater mogul Harry J. Nederlander and stepdaughters of Levine, the sisters said their family has been affected by breast cancer.

Our grandfather wanted to give us the opportunity to make a difference in the world. With our gift, we hope to make sure that more women in our local community have more access to advanced screening, treatment and care, they said.

Manker calls the proximity of the center to the Village a natural since, in 1969, the Golden Rain Foundation contributed the first $100 toward the future Saddleback Community Hospital (now MemorialCare Saddleback Medical Center) and 9 acres of land, sold for $1. The hospital opened in 1974.

Read more here:
Work starts on Womens Health Pavilion in Laguna Hills - OCRegister

A single star may adorn the Texas state flag but the life sciences ecosystem is comprised of a galaxy of brightly shining companies such as FUJIFILM Diosynth Biotechnologies, Taysha Gene Therapies and Veravas developing innovative new medicines, diagnostics and medical devices.

The growth of the quickly rising Lone Star Bio life sciences hub is fueled by financial support from the state government in the form of the multi-billion dollar Cancer Prevention Research Institute of Texas fund and the drug discovery research coming out of the states universities. Baylor College of Medicine and Texas A&M headline the list of academic powerhouses.

Thats where it all begins. Most research that results in drug discovery generally starts at universities, said Andrew Strong, a partner at Houston-based Hogan Lovells, a legal firm representing biotech clients across Texas and the United States, in an interview with BioSpace.

Barry Burgdorf, also an attorney with Hogan Lovells, echoed Strongs statement. There is a ton of great IP spinning out of the universities, he said. That research is fueling a number of startups across the state, as well as legacy pharma companies that are licensing the developmental programs. That, in turn, is strengthening the ecosystem, Burgdorf noted.

Although the slowing economy is reducing expenditures of venture capital, Burgdorf and Strong agreed that in Texas, there has been no slowdown of new technologies being developed in the universities.

Texas is still very focused on growth [and] recruiting companies, Burgdorf said.

Real estate prices are also attractive to companies hoping to set up shop in Texas, especially when compared to other major U.S. hubs such as Boston and San Francisco.

Lower Cost Real Estate

The per-square-foot cost for space in the Boston area is approximately $95.57, according to Pete Briskman, executive managing director and co-lead for JLLs Mid-Atlantic life sciences practice. In the Bay Area, the per-square-foot cost is $82.41. This compares to $22 per square foot In Houston. Briskman said the difference is critical to companies as it can help them build out space and hire new employees.

He said companies used to have a mantra that the real estate costs were less significant than the science. When it comes to a place like Texas where a company is saving tens of millions of dollars, however, it becomes a real consideration.

Strong agreed with that assessment. He relayed that the CEO of a Boston area biotech told him real estate needs were taking up seven percent of its annual budget. The money can go much farther in Texas, he said.

Strong pointed to the August decision of Cellipont Bioservices to relocate to Texas from San Diego. Cellipont, a cell therapy contract development and manufacturing organization, plans to build a 76,000-square-foot facility in the state.

Strong was the founding chief executive officer of Kalon Biotherapeutics, a startup biotech spun out of the A&M system. He sold the company to FUJIFILM.

Strong pointed to the significant investments FUJIFILM has made. Those expenses are having a positive ripple effect across the region. For every one of the 1,000 FUJIFILM jobs in Texas with a salary of more than $80,000, six additional jobs have been created because of these investments, he said.

FUJIFILMs Ever-Expanding Footprint

Since its 2014 arrival in Texas, FUJIFILM Diosynth Biotechnologies (FDB)s contract manufacturing operations in College Station have rapidly expanded and changed the landscape of the ecosystem across the Brazos Valley region. The Japan-based company has invested hundreds of millions of dollars into its facility, expanding its offerings to bolster the development of gene therapies. The College Station facility has become the largest single-use CDMO production campus in the United States.

In 2019, FUJIFILM established anew Gene Therapy Innovation Center. One year later, the federal government selected the College Station facility to support COVID-19 vaccine candidate manufacturing at its Flexible Biomanufacturing Facility.

In December 2021, FUJIFILM announced another investment to expand its services in Texas and in June, it provided additional finances to expand its continuous processing technologies.

Gerry Farrell, chief operating officer at FDB Texas, told BioSpace thecompany's expansions within Texas have been supported by a strong partnership with state and local governments, as well as the universities.

Tayshas Gene Therapies for Rare and Orphan Diseases

Dallas-based Taysha started the year with disappointing news from its experimental gene therapy for Sandhoff and Tay-Sachs diseases, two forms of GM2 gangliosidosis. A patient treated with TSHA-101, a bicistronic vector, died. However, the patient did not succumb to complications from the gene therapy. They died after contracting a hospital-acquired methicillin-resistant staphylococcus aureus (MRSA) infection while being treated for COVID-19.

Although the death was related to the infection, the independent review board determined a review of the data was warranted.

In addition to TSHA-101, Taysha is also developing AAV-based gene therapies for the treatment of monogenic diseases of the central nervous system in both rare and large patient populations. In its quarterly financial report issued in August, the companyhighlighted positive momentum with its gene therapy for giant axonal neuropathy.

Taysha received orphan drug and rare pediatric disease designations from the FDA and orphan drug designation from the European Commission for TSHA-120, an AAV9 gene therapy. Data showed GAN patients treated with TSHA-120 have seen durable improvement and recoverability of sensory nerve amplitude potential (SNAP), a definitive clinical endpoint, the company noted in its announcement.

Taysha is also developing a gene therapy for Rett Syndrome. TSHA-102 is the first-and-only gene therapy in clinical development for Rett. It has also received orphan drug and rare pediatric disease designations from the FDA and has been granted orphan drug designation from the European Commission.

Veravas Antibody Detection Platform

Based in Austin, Veravas launched in 2017. The company has developed the VeraPrep Antibody Detection Platform. The platform uses proprietary magnetic beads to pre-analytically clean samples to remove problematic heterophilic and autoantibody interference, according to the company. The clean sample allows for better capture and measurement of targeted IgA, IgG and IgM immunoglobulins.

During the COVID-19 pandemic, Veravas used its platform to develop an antibody test for SARS-CoV-2.

Baylor Genetics' Pandemic Contributions

A pioneer in genetic testing, Houston-based Baylor Genetics offers a range of diagnostic sequencing and analysis. The company provides a full spectrum of cost-effective, genetic testing it claims leads to clinically relevant solutions.

Baylor offers whole exome and genome sequencing services that provide data for point mutations, insertions and deletions. Oncology testing can find mutation panels through next-generation sequencing.

The company also provides prenatal diagnostics, molecular diagnostics and cytogenetics.

During the height of the COVID-19 pandemic, Baylor launched a combination test for the SARS-CoV-2 virus, as well as influenza A and B.

Asuragen

Also based in Austin, molecular diagnostics company Asuragen, a Bio-Techne brand, provides streamlined solutions for genetics, oncology, controls and companion diagnostic needs.

One of Asuragens products is AmplideX, a genetic test for Fragile X syndrome, whichcauses mild to severe intellectual disability and is associated with autism spectrum disorder.

Beyond Fragile X, Asuragen offers a chronic myeloid leukemia monitoring kit.

More here:
5 Life Science Companies Drive Innovation in Lone Star Bio - BioSpace