- Chicago-based AveXis, Inc. plans to use a single-arm design for a pivotal study of its spinal muscular atrophy (SMA) drug, the gene therapy company said November 1.
- The study, which will enroll about 20 patients, won't test AVXS-101 against a placebo. Instead, results will be compared to historical progression of this severe neuromuscular disease.
- AveXis announced the new trial plans following what it characterized as a "positive" Type B meeting with the Food and Drug Administration in September. AveXis' drug, which targets patients with type 1 SMA, could compete with Biogen's nusinersen.
AveXis President and CEO Sean Nolan said the pivotal study is slated to begin in the first half of 2017. A Phase 1 trial of AVXS-101 is ongoing and the company plans to run the single-arm pivotal trial in parallel.
"We believe the Type B meeting had a positive tone, with FDA offering a number of constructive suggestions which we believe will better enable implementation of a pivotal study design that is most appropriate for the patients suffering from this devastating disease," Nolan said.
The FDA suggested AveXis design the study with co-primary endpoints to assess developmental achievements as well as survival. Regulators also recommended AveXis request an end-of-Phase 1 meeting following conclusion of that study.
Shares in AveXis climbed 22% on the news in Wednesday trading.
Avexis' positive FDA feedback might help it close the gap between AVXS-101 and Biogen's more advanced nusinersen in Type 1 SMA, analysts at Jefferies said. Biogen recently indicated the FDA had accepted its new drug application for nusinersen for priority review based on interim data from a Phase 3 study and other open-label data.
Biogen's "first mover advantage" could limit uptake of AVXS-101, Jefferies analysts said, noting nusinersen is also being evaluated for Type 2/3 SMA — a potentially significant market opportunity.
As a one-time gene therapy for SMA, AVXS-101 could offer a more convenient dosing regimen for type 1 SMA patients however.
“We would not rule out the possibility the therapies could be used in the same patients, though pricing could be an issue. We currently model a 2017 nusinersen launch with probability-adjusted revenues potentially reaching $1.5B by 2025,” the analysts stated.