Back to top

Image: Bigstock

Sarepta's (SRPT) DMD Gene Therapy Study Data Fails to Impress

Read MoreHide Full Article

Sarepta Therapeutics (SRPT - Free Report) announced top-line data from part 2 of the mid-stage study — SRP-9001-102 (Study 102) — evaluating its lead gene therapy candidate, SRP-9001, in children with Duchenne muscular dystrophy ("DMD").

The double-blind, placebo-controlled Study 102 is evaluating the safety, efficacy and tolerability of a single dose of SRP-9001 in 41 patients with DMD. Part 2 of the study evaluated SRP-9001 in all 21 patients in the placebo-arm during part 1 of the study.

Data from part 2 of the study demonstrated that treatment with SRP-9001 led to an improvement of statistically significant 2.0 points on the mean North Star Ambulatory Assessment (“NSAA”) at 48 weeks versus propensity-score weighted external controls. While NSAA score improved by 1.3 points from baseline for SRP-9001 treated DMD patients, the NSAA score declined 0.7 points for the external control group.

The NSAA scale is used to measure functional motor abilities in children with DMD.

Please note that the external control group was a defined group of DMD patients, matched for variables including age, steroid usage, baseline NSAA and timed function tests with the participants in Study 102.

However, the improvement in the NSAA score failed to meet market expectations. Shares of Sarepta declined 11% on Jan 10, following the data readout. In fact, Sarepta’s shares have declined 12.8% in the past year compared with the industry’s decrease of 31.3%.

Zacks Investment ResearchImage Source: Zacks Investment Research

We note that Sarepta’s stock crashed almost 50% in January 2021 following the announcement of the data from part 1 of Study 102, where SRP-9001 failed to achieve statistical significance in improving NSAA score compared to placebo. However, the study had met the primary biological endpoint of micro-dystrophin protein expression.

In May 2021, Sarepta announced promising data from an open-label study — ENDEAVOR — evaluating commercially representative material for SRP-9001. Data from the study demonstrated robust expression of micro-dystrophin, a protein that helps to strengthen muscle fibers.

The company initiated a pivotal study — EMBARK — to evaluate the commercially representative material for SRP-9001 in October last year.

Sarepta is developing the micro-dystrophin-encoding gene therapy candidate in collaboration with Roche (RHHBY - Free Report) .

Sarepta and Roche entered into a licensing agreement to develop SRP-9001 in 2019. Per the agreement, Roche has exclusive rights to launch and commercialize SRP-9001 in the ex-U.S. markets. Roche made a $1.15-billion upfront payment and will pay up to $1.7 billion in regulatory and sales milestones to Sarepta.

Sarepta is currently the leading gene therapy player in the DMD space. However, several other companies, including Pfizer (PFE - Free Report) and REGENXBIO (RGNX - Free Report) , are also developing their gene therapy candidates for treating DMD.

Pfizer began dosing in the phase III CIFFREO study on its gene therapy candidate, PF-06939926, last December. The study is evaluating the safety and efficacy of its gene therapy candidate for treating DMD. Pfizer is the closest competitor of Sarepta in developing a DMD gene therapy with both companies evaluating their respective candidates in late-stage studies. Pfizer’s DMD candidate enjoys fast track, orphan drug and rare pediatric disease designations in the United States.

REGENXBIO plans to start a clinical study next year to evaluate its gene therapy candidate RGX-202 for treating DMD. RGX-202 was designed using REGENXBIO's proprietary NAV AAV8 vector to deliver an optimized microdystrophin transgene to develop a targeted therapy for improved resistance to muscle damage associated with DMD. REGENXBIO received an orphan drug designation for the candidate earlier this month.

Zacks Rank

Sarepta currently carries a Zacks Rank #3 (Hold). You can see the complete list of today’s Zacks #1 Rank (Strong Buy) stocks here.