AveXis Plans a May Start for Phase 3 European Trial of Its SMA Type 1 Gene Therapy

AveXis’ expects to start a Phase 3 clinical trial of its spinal muscular atrophy (SMA) gene therapy AVXS-101 in Europe in May.

The STR1VE-EU trial (NCT03461289) is expected to include up to 30 children under 6  months of age with type 1 SMA, the disease‘s most severe and common form. All will receive a single dose of intravenous AVXS-101.

The therapy’s safety and effectiveness will be assessed regularly until the babies reach 18 months. At that point, their parents can allow those who are eligible to take part in a long-term follow-up study.

Researchers will be looking at whether the infants can sit without support and also the number who survive until 14 months of age.

The trial will be conducted in Belgium, France, Germany, Italy, the Netherlands, Spain, Sweden, and the U.K. It is expected to be completed in November 2020.

AVXS-101 contains a normal version of the SMN gene that is defective in SMA. Movement nerve cells need a normal version to survive and thrive.

AveXis delivers the gene with a non-infectious virus. The company designed it to be a one-time treatment to prevent muscle degeneration over a lifetime, it said in a recent interview with SMA News Today.

Babies who take part in the STR1VE-EU trial must have mutations of both SMN1 alleles and one or two copies of SMN2. Alleles are gene variations. In most cases, the more copies a patient has of SMN2, the less severe the disease will be.

AveXis has already conducted a Phase 1 trial (NCT02122952) of AVXS-101 in 15 type 1 SMA infants, who received the therapy before they reached six months of age.

The key finding was that all of the children survived for 20 months. This was a huge improvement over what normally happens — 92 percent of children dying by that age.

Another stunning result was that 11 of the 12 children who received the high dose of the therapy were able to sit unassisted, eat food through their mouth, and speak. Nine were able to roll over, and two could walk without help.

AveXis continues to recruit participants for its ongoing STR1VE Phase 3 trial (NCT03306277) in the United States. The trial is also looking at AVXS-101’s safety and effectiveness in children with type 1 SMA who are less than 6 months old. Results similar to those seen in the completed Phase 1 study were observed in the first three children dosed, AveXis said.

Meanwhile, the company continues to recruit patients for its ongoing STRONG Phase 1 trial (NCT03381729) in children up to 60 months of age with type 2 SMA. Unlike the studies in type 1 SMA, which use intravenous therapy administration, patients in the STRONG trials will receive AVXS-101 in the spinal canal, which enables a more targeted treatment.

AveXis also plans the SPRINT trial program for infants under 6 weeks of age with no symptoms but who are likely to develop SMA types 1, 2, or 3, and the REACH program for types 1-3 SMA patients ages 6 months to 18 years who are ineligible for the other studies.

SPRINT and REACH will be worldwide trials. SPRINT is expected to start by mid-2018 and REACH by late 2018 or early 2019.

AveXis and France-based Genethon, which developed AVXS-101, recently announced an agreement granting AveXis the rights to patents in the U.S., Europe and Japan that cover Genethon’s AAV9 SMN gene therapy technology and delivery system. They cover delivery by IV and the spinal canal.