AVXS-201, Gene Therapy for Rett, Again Moving Toward Clinical Trial, AveXis Says

Most animal studies needed to support plans to move AVXS-201 — AveXis’ investigational gene therapy for Rett syndrome — into clinical testing in patients are complete, the company reports.

AveXis hopes to soon start meeting with the U.S. Food and Drug Administration (FDA) in advance of filing a revised investigational drug (IND) application, requesting the right to open a clinical trial of the gene therapy candidate.

The trial’s launch date will depend on the FDA’s acceptance of the revised IND application.

“Looking ahead to the coming months, we will be working closely with the FDA to progress AVXS-201 forward toward an IND submission,” the therapy’s development team said in a statement letter to the Rett community. A link to the letter was shared in a Twitter post by Rett UK.

“We look forward to continuing to collaborate closely with the Rett community, and commit to providing you with updates on a regular basis as we have more information available to share,” the team added.

The Novartis-owned company decided to withdraw its original IND, delaying a possible launch of an AXS-201 trial, in 2019 after reports surfaced of data manipulation that led to inaccuracies in its FDA application that supported approval of Zolgensma, a gene therapy for spinal muscular atrophy (SMA) patients up to age 2.

Both AVXS-201 and Zolgensma use the same adeno-associated virus (AAV) vector, called AAV9, to deliver normal copies of the defective genes that cause the diseases — MECP2 in the case of Rett, and SMN1 in SMA — to patient cells.

AveXis decided to repeat or conduct new animal studies, as well as additional quality control checks, to have a more “robust data package” for the company’s revised IND request for AXS-201.

“We recognize the significant unmet need among patients with Rett syndrome, and understand that these delays were a cause for concern. Today, we are pleased to let you know that most of these preclinical studies are now complete,” AveXis stated in its letter.