Friedreich’s ataxia: clinical features, pathogenesis and management

A Cook, P Giunti; British Medical Bulletin,  2017, 1–12 doi:10.1093/bmb/ldx034

The last decade has seen important advances in our understanding of the pathogenesis of disease. In particular, the genetic and epigenetic mechanisms underlying the disease now offer promising novel therapeutic targets.
The search for effective disease-modifying agents continues. It remains to be determined whether the most effective approach to treatment lies with increasing frataxin protein levels or addressing the metabolic consequences of the disease, for example with antioxidants.
Management of Freidreich’s ataxia is currently focussed on symptomatic management, delivered by the multidisciplinary team. Phase II clinical trials in agents that address the abberrant silencing of the frataxin gene need to be translated into large placebo-controlled Phase III trials to help establish their therapeutic potential.

Incidence et caractéristiques de la scoliose neurologique dans l’ataxie de Friedreich à maturité osseuse

Jean Meyblum, Anne-Laure Simon, Christophe Vidal, Isabelle Husson, Bastien Roche, Brice Ilharreborde, Revue de Chirurgie Orthopédique et Traumatologique, Volume 103, Issue 7, Supplement, November 2017, Page S52, ISSN 1877-0517, doi:10.1016/j.rcot.2017.09.072.

L’incidence de la déformation scoliotique est élevée dans l’AF (74 % de la cohorte). Il n’existe pas de prévalence d’un type particulier de courbure. L’hypercyphose thoracique était fréquemment retrouvée sans être associée à un type de scoliose, témoignant du déséquilibre antérieur de la marche cérébelleuse. L’arthrodèse rachidienne n’a pas fait perdre la marche chez les patients marchant encore au moment de la chirurgie.

Cardiomyopathy in Friedreich’s Ataxia

Pablo Salazar, Raksha Indorkar, Michael Dietrich, Afshin Farzaneh-Far; European Heart Journal, , ehx607, doi:10.1093/eurheartj/ehx607

A 27-year old man with Friedreich’s Ataxia was referred for cardiac evaluation. He had no cardiac symptoms, and his physical exam was remarkable for an ataxic-gait and increased muscle tone.

Nrf2-Inducers Counteract Neurodegeneration in Frataxin-Silenced Motor Neurons: Disclosing New Therapeutic Targets for Friedreich’s Ataxia

Petrillo, S.; Piermarini, E.; Pastore, A.; Vasco, G.; Schirinzi, T.; Carrozzo, R.; Bertini, E.; Piemonte, F.; Int. J. Mol. Sci. 2017, 18, 2173. doi:10.3390/ijms18102173

In FA, the dys-regulation of cellular antioxidant defenses, due to frataxin deficiency, exacerbates oxidative stress, thus the Nrf2 activation becomes more and more of an attractive strategy for the treatment of this disease.

Overall, our findings support Nrf2 as a therapeutic target for FA, and its induction as a promising approach to prevent or slow the pathological changes observed in this disease. Furthermore, the Nrf2 impairment mirrored at the systemic level in PBMCs of patients may help to open new perspectives for biomarker research in FA, potentially useful for monitoring clinical trials.

Sustained FXN expression in dorsal root ganglia from a nonreplicative genomic HSV-1 vector

Maria Ventosa, Zetang Wu and Filip Lim; The Journal of Gene Medicine, Accepted manuscript online: 17 OCT 2017 08:40PM EST DOI: 10.1002/jgm.2993

With the aim of developing a gene therapy for FA neuropathology, here we describe the construction and preliminary characterization of a high capacity nonreplicative genomic herpes simplex virus type 1 vector (H24B-FXNlac vector) carrying a reduced version of the human FXN genomic locus, comprising the 5 kb promoter and the FXN cDNA with the inclusion of intron 1.

We show that the transgene cassette contains the elements necessary to preserve physiological neuronal regulation of human FXN expression. Transduction of cultured fetal rat dorsal root ganglion neurons with the H24B-FXNlac vector results in sustained expression of human FXN transcripts and frataxin protein. Rat footpad inoculation with the H24B-FXNlac vector results in human FXN transgene delivery to the dorsal root ganglia, with expression persisting for at least 1 month.

Our results support the feasibility of using this vector for sustained neuronal expression of human frataxin for FA gene therapy.

BioMarin Selects BMN 290 for Friedreich's Ataxia

SAN RAFAEL, Calif., Oct. 18, 2017 /PRNewswire/ -- BioMarin Pharmaceutical Inc. (NASDAQ: BMRN) updated the investment community on the Company's development portfolio, which is focused on innovative therapies to treat rare and ultra-rare diseases.
BioMarin announced today that it has selected BMN 290, a selective chromatin modulation therapy, for the treatment of Friedreich's Ataxia (FA). FA is a rare autosomal recessive disorder with worldwide prevalence of approximately 15,000, which results in disabling neurologic and cardiac progressive decline. Currently there are no approved disease modifying therapies for FA. In preclinical models, BMN 290 increases frataxin expression in affected tissues more than two-fold. BMN 290 is a second generation compound derived from a compound acquired from Repligen that had human clinical data demonstrating increases in frataxin in FA patients. BMN 290 was selected for its favorable penetration into the central nervous system and cardiac target tissues, and its preservation of the selectivity of the original Repligen compound. The company expects to submit the IND in 2H 2018.

New data for Friedreich's ataxia with a novel capsid demonstrate reversal of disease phenotype in a preclinical disease model.

Press Release: CAMBRIDGE, Mass., Oct. 17, 2017 (GLOBE NEWSWIRE) -- Voyager Therapeutics, Inc. (NASDAQ:VYGR), a clinical-stage gene therapy company focused on developing life-changing treatments for severe neurological diseases announced today multiple data presentations at the Congress of the European Society of Gene and Cell Therapy (ESGCT) taking place October 17-20, 2017, in Berlin, Germany. The data include an oral presentation related to recent results from Voyager's ongoing Phase 1b trial of VY-AADC01 in advanced Parkinson's disease, as well as six poster presentations related to Voyager's novel adeno-associated virus (AAV) capsid optimization efforts, gene therapy manufacturing, and preclinical pipeline programs.

Rescue of Central and Peripheral Neurological Phenotype in a Novel Mouse Model of Friedreich's Ataxia by Intravenous Delivery of AAV Frataxin." Poster P107.

Friedreich's ataxia is a severe, inherited neurological disease caused by mutations in the frataxin gene leading to decreased expression of frataxin (FXN), which results in severe sensory impairment, progressive loss of the ability to walk, generalized weakness, loss of sensation, as well as severe and potentially fatal cardiomyopathy. In a transgenic mouse model of FA, one-time intravenous post-symptomatic dosing of an AAV vector composed of a novel AAV capsid and a frataxin transgene, together with intracerebral dosing also delivering a frataxin transgene, rapidly halted and reduced FA disease progression in multiple tests including three functional tests of motor behavior and one electrophysiological test. In addition, increasing intravenous vector doses with the same novel capsid together with a fixed dose of the intracerebral vector led to a dose-dependent rescue of the FA phenotype. This novel AAV capsid provided at least 20-fold greater delivery of the vector to sensory ganglia as measured by vector genomes, and approximately a three-fold greater expression of frataxin in the cerebellum, as compared to an AAV9 vector at a similar dose. Additional preclinical studies are underway at Voyager including steps to optimize a lead clinical candidate for the treatment of FA.

New data for Friedreich's ataxia with a novel capsid demonstrate reversal of disease phenotype in a preclinical disease model.

Recombinant adeno-associated viral vector serotype 5 carrying the gene for the human frataxin protein for the treatment of Friedreich’s ataxia

EU/3/17/1906: Public summary of opinion on orphan designation (First published: 17/10/2017): On 23 August 2017, orphan designation (EU/3/17/1906) was granted by the European Commission to Voisin Consulting S.A.R.L., France, for recombinant adeno-associated viral vector serotype 5 carrying the gene for the human frataxin protein (also known as AGIL-FA) for the treatment of Friedreich’s ataxia.
What is the stage of development of this medicine?:
The effects of the medicine have been evaluated in experimental models.
At the time of submission of the application for orphan designation, no clinical trials with this medicinein patients with Friedreich’s ataxia had been started.
At the time of submission, the medicine was not authorised anywhere in the EU for Friedreich’s ataxia.
Orphan designation of the medicine had been granted in the United States for this condition.

Therapies for mitochondrial diseases and current clinical trials

Ayman W. El-Hattab, Ana Maria Zarante, Mohammed Almannai, Fernando Scaglia, In Molecular Genetics and Metabolism, 2017, , ISSN 1096-7192, doi:10.1016/j.ymgme.2017.09.009.

Mitochondrial diseases are a clinically and genetically heterogeneous group of disorders that result from dysfunction of the mitochondrial oxidative phosphorylation due to molecular defects in genes encoding mitochondrial proteins. Despite the advances in molecular and biochemical methodologies leading to better understanding of the etiology and mechanism of these diseases, there are still no satisfactory therapies available for mitochondrial disorders. Treatment for mitochondrial diseases remains largely symptomatic and does not significantly alter the course of the disease. Based on limited number of clinical trials, several agents aiming at enhancing mitochondrial function or treating the consequences of mitochondrial dysfunction have been used. Several agents are currently being evaluated for mitochondrial diseases. Therapeutic strategies for mitochondrial diseases include the use of agents enhancing electron transfer chain function (coenzyme Q10, idebenone, riboflavin, dichloroacetate, and thiamine), agents acting as energy buffer (creatine), antioxidants (vitamin C, vitamin E, lipoic acid, cysteine donors, and EPI-743), amino acids restoring nitric oxide production (arginine and citrulline), cardiolipin protector (elamipretide), agents enhancing mitochondrial biogenesis (bezafibrate, epicatechin, and RTA 408), nucleotide bypass therapy, liver transplantation, and gene therapy. Although, there is a lack of curative therapies for mitochondrial disorders at the current time, the increased number of clinical research evaluating agents that target different aspects of mitochondrial dysfunction is promising and is expected to generate more therapeutic options for these diseases in the future.

In Vivo Assessment of Mitochondrial Dysfunction in Clinical Populations Using Near-Infrared Spectroscopy

T. Bradley Willingham and Kevin K. McCully, Front. Physiol., 14 September 2017 doi:10.3389/fphys.2017.00689

The ability to sustain submaximal exercise is largely dependent on the oxidative capacity of mitochondria within skeletal muscle, and impairments in oxidative metabolism have been implicated in many neurologic and cardiovascular pathologies. Here we review studies which have demonstrated the utility of Near-infrared spectroscopy (NIRS) as a method of evaluating of skeletal muscle mitochondrial dysfunction in clinical human populations.

In FRDA, NIRS measures of mitochondrial capacity in the forearm were inversely correlated with feelings of low energy, suggesting that mitochondrial function may be related to fatigue in persons with FRDA across the spectrum of symptom severity (Bossie et al., 2016). These findings lend support to the use of NIRS measures of mitochondrial capacity as measure of muscle dysfunction in persons with FRDA during interventions or over the course of disease progression.

There are currently no physiological evaluation tools available for clinicians diagnosing and treating patients with mitochondrial disease, and the application of NIRS may offer a relevant, in vivo measure of mitochondrial function in this population. To date, Friedreich's ataxia is the only mitochondrial disease to be evaluated using NIRS, and establishing the usefulness of NIRS in evaluating mitochondrial dysfunction in persons with mitochondrial disease warrants further investigation.