Efgartigimod Effective Across Subgroups, FDA to Hold AdComm Meeting on SRP-9001, Reboxetine Demonstrates Positive Effect on Obstructive Sleep Apnea

Welcome to this special edition of Neurology News Network. I’m Marco Meglio.

When grouping patients by clinical characteristics such as time from diagnosis, thymectomy status, and concomitant medications, new findings from the phase 3 ADAPT study showed that efgartigimod is consistently affective across subgroups of individuals with generalized myasthenia gravis (gMG). The study featured 129 patients with AChR antibody positive gMG who received intravenous efgatigimod 10 mg/kg or placebo in cycles of 4 weekly infusions, with subsequent cycles based on clinical evaluation. In those who had less than 3 years since diagnosis, 76.8% of efgartigimod-treated patients demonstrated at least a 2-point improvement for at least 4 consecutive weeks on Myasthenia Gravis Activities of Daily Living (MG-ADL) vs 23.5% of those on placebo. In non-thymectomized patients, 85.0% (17 of 20) on efgartigimod achieved responder status vs 32.4% (11 of 34) of those on placebo.

In advance of the upcoming regulatory action deadline for Sarepta Therapuetics’ investigational gene therapy for the treatment of Duchenne muscular dystrophy (DMD), SRP-9001, the FDA has determined it will hold an advisory committee (AdComm) meeting. The current Prescription Drug User Fee Act action date for the treatment’s biologics license application (BLA) is set for May 29, 2023. The BLA is supported by positive data from the phase 1/2 Study SRP-9001-101, the phase 2 SRP-9001-102 study, and the phase 1 ENDEAVOR study. SRP-9001 is also currently being evaluated in the double-blind, randomized, placebo-controlled EMBARK study,, which was proposed as the post-marketing confirmatory study to support an accelerated approval. EMBARK is primarily assessing change in NSAA total score from baseline to week 52 compared with placebo, though secondary end points included a variety of other outcomes, such as microdystrophin expression, time to rise from floor, Timed Stair Ascend 4 Steps, and Stride Velocity 95th Centile tests, among others.

Findings from a small-scale study of patients with obstructive sleep apnea (OSA) showed that treatment with single doses of 4 mg reboxetine, a selective NaRI, modestly reduces the frequency of respiratory events and improves overnight oxygenation and snoring. The addition of oxybutynin, a medication typically used to treat overreactive bladder, had mild sedative effects but did not produce additive benefit in reducing OSA severity on a single night despite modest improvements in pharyngeal muscle compensation. At the conclusion of the analysis, reboxetine alone reduced the apnea-hypopnea index (AHI3) by 5.4 events/h (95% CI, –10.4 to –0.3; P = .03) in comparison with placebo, whereas the combination of reboxetine and oxybutynin was not significantly different (4.2 events/h; 95% CI, –9.6 to 1.1; P = .11).