AveXis to Initiate Screening for Remaining Patients in Pivotal Trial of AVXS-101 for SMA Type 1 Following Review of Preliminary Data from First Three Patients

Chicago, Ill. (January 30, 2018) – AveXis, Inc. (NASDAQ: AVXS), a clinical-stage gene therapy company developing treatments for patients suffering from rare and life-threatening neurological genetic diseases, today announced that, following review of safety data and early signals of efficacy from the first three patients dosed in its pivotal trial of AVXS-101 for spinal muscular atrophy (SMA) Type 1, the company, with agreement from the U.S. Food and Drug Administration, will initiate screening for the remaining patients in the trial as per the protocol.

The open-label, single-arm, multi-center trial (STR1VE) is designed to evaluate the efficacy and safety of a one-time intravenous (IV) infusion of AVXS-101. There was at least a four-week interval scheduled between dosing the first three patients to allow review of the safety analysis as well as early signals of efficacy.

“We are pleased to share that we will be initiating screening for the remaining patients to be enrolled in STR1VE as planned, following review of safety data and early signals of efficacy from the first three patients who received a one-time IV infusion of AVXS-101,” said Dr. Sukumar Nagendran, Chief Medical Officer of AveXis. “We know there is an urgent need for new treatment approaches, and we are eager to rapidly enroll the remaining patients in the pivotal trial as we further our clinical understanding of AVXS-101.”

The trial will enroll a minimum of 15 patients with SMA Type 1 who are less than six months of age at the time of gene therapy, and who have one or two copies of the SMN2 backup gene as determined by genetic testing and bi-allelic SMN1 gene deletion or point mutations. The intent-to-treat population is defined as patients who are less than six months of age and symptomatic at the time of gene therapy, with two copies of the SMN2 gene as determined by genetic testing, bi-allelic SMN1 gene deletion and no c.859G>C mutation in SMN2.