AveXis presents update on its gene therapy trial for spinal muscular atrophy

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AveXis, a clinical-stage gene therapy company specialized in the development of treatments for orphan and life-threatening neurological diseases, has presented interim data of its Phase 1 gene therapy trial for the treatment of spinal muscular atrophy (SMA).

AVXS-101 is a gene therapy candidate developed for the one-time treatment of SMA type 1 and is the only gene therapy in development for SMA. The data presented by Dr Jerry Mendell of Nationwide Children’s Hospital, at the 21st International Annual Congress of the World Muscle Society in Spain revealed the favourable safety profile of AVXS-101 and showed that the treatment was generally well tolerated by the subjects, with no new treatment-related concerns identified.

SMA is a severe neuromuscular disease characterized by the loss of motor neurons leading to progressive muscle weakness and paralysis. It results from a genetic defect in the SMN1 gene which codes for the survival motor neuron (SMN) protein, and affects all muscles in the body. There is no effective treatment for SMA and current drug therapy has been unsuccessful in stabilizing or reversing this disease. SMA Type 1 is one of the leading genetic cause of infant mortality.

Interim data of the second cohort of patients who received the proposed therapeutic dose of gene therapy showed that the patients achieved key motor development milestones as of mid-September 2016. Of the total 12 patients in this cohort, 8 have achieved the ability to sit unassisted, 11 achieved head control, 7 has acquired the ability to roll over completely and 11 could sit with support. Two patients who had achieved earlier and important developmental milestones such as crawling, standing with support, standing alone and walking with support have now started walking independently.

The trial is designed as an open-label, dose escalation study to determine the safety and efficacy of gene transfer in SMA type 1 patients. The procedure involves intravenous injection of AVXS-101 through a peripheral limb vein and short-term safety will be evaluated over a period of two years. Patients will be tested at baseline and return for follow up visits on days 7, 14, 21, 30, followed by once every month through 12 months’ post dose, and then every three months through two years post infusion. The trial is expected to complete in December 2017.

Sean P. Nolan, president and CEO of AveXis commented: “To date, the majority of patients who received the proposed therapeutic dose of AVXS-101 have achieved key milestones and two-thirds of these patients can sit independently – a fact completely inconsistent with the known disease course, as children with untreated SMA Type 1 will never sit unassisted. We are encouraged by these interim data, and continue to work diligently to bring this gene therapy to the children suffering from this devastating condition.”

Source: Early data win for AveXis’ SMA Type 1 therapy but Biogen’s med also strong; Press Release.