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Brighton, United Kingdom. – October 5, 2015 – AveXis, Inc., a clinical stage gene therapy company developing treatments for rare and life-threatening neurological genetic diseases, presented data from its ongoing Phase 1/2 trial of AVXS-101, the company’s initial product candidate for the treatment of spinal muscular atrophy (SMA) Type 1, at the International Congress of the World Muscle Society in Brighton, United Kingdom.
Dr. Jerry R. Mendell, Director of the Center for Gene Therapy at The Research Institute at Nationwide Children’s Hospital (NCH) in Columbus, Ohio and lead investigator in the study, reported preliminary observations from the ongoing study including survival data which indicated that none of the patients in this study have reached an “event”, which is defined as death or until a patient requires at least 16 hours of continuous respiratory assistance for at least two weeks in the absence of an acute reversible illness. Additionally, Dr. Mendell described the motor function improvement observed in all patients, as measured by The Children’s Hospital of Philadelphia Infant Test of Neuromuscular Disorders (CHOP-INTEND), a test developed to measure motor skills of patients with SMA Type 1. All patients in this study showed improvement in CHOP-INTEND scores, with modest improvement in the low-dose treatment group and greater improvement in the mid-dose treatment group.
Dr. Mendell stated that AVXS-101 appears to be generally safe and well tolerated in the patients studied to date. Of the five Serious Adverse Events (SAEs) reported in the presentation, three patients developed upper respiratory infections that were considered unrelated to study treatment and two patients experienced an increase in liver enzymes (one in each treatment group). The liver enzyme elevations were without clinical manifestations and were subsequently resolved following steroid treatment.
“These initial observations in safety, survival and motor function are compelling and encouraging in all patients to date in this Phase 1/2 study, suggesting that AVXS-101 appears to be a promising treatment for patients suffering from SMA Type 1,” said Dr. Mendell.
Phase 1/2 Trial Design
The open-label study is designed to evaluate safety and efficacy of AVXS-101 in patients suffering from SMA Type 1. The primary outcome in the study is safety and tolerability. The secondary outcome measure is an efficacy measure as defined by the time from birth to an “event.” Exploratory outcome measures include muscle assessment studies, measured by a patient’s CHOP-INTEND score.
Data reported by Dr. Mendell included nine patients who met enrollment criteria with disease onset at birth to six months and proven mutations of SMN1 with two copies of SMN2 without the c.859G>C exon 7 modifier. There were two dosing cohorts, consisting of three patients in a low-dose cohort (6.7 X1013 vg/kg) and six patients in a mid-dose cohort (2.0 X1014 vg/kg). The low-dose cohort included subjects at 6-7 months of age, while the mid dose included six subjects at ages 2-8 months. The clinical protocol requires that each patient remain at NCH for 48 hours after dosing for monitoring and is subsequently discharged. For one month after dosing, weekly follow-up evaluations are conducted, and after the first month, additional monthly evaluations are conducted for the duration of the study.
SMA is a severe neuromuscular disease characterized by the loss of motor neurons leading to progressive muscle weakness and paralysis. SMA is caused by a genetic defect in the SMN1 gene that codes SMN, a protein necessary for survival of motor neurons. The incidence of SMA is approximately one in 10,000 live births.
The most severe form of SMA is Type 1, which results in an inability to sit without support, difficulty in breathing and swallowing, and is lethal for greater than 90 percent of patients by 2 years of age. SMA Type 1 is the second most common life-shortening autosomal recessive disorder after cystic fibrosis and the leading genetic cause of infant mortality.
About AveXis, Inc.
AveXis is a clinical-stage gene therapy company developing treatments for rare and life-threatening neurological genetic diseases. The company’s initial product candidate, scAAV9.CB.SMN (AVXS 101), is in an on-going Phase 1 clinical trial for the treatment of SMA Type 1. For more information about AveXis, please visit www.avexis.com.