Since the Duchenne muscular dystrophy filing for Sarepta’s Vyondys 53 was knocked back by the US FDA in August the group’s stock has lost over 30%. The 7% lift this morning, from an update on the limb-girdle muscular dystrophy project Sarepta acquired through Myonexus, thus brought welcome relief. This was the first time Sarepta had detailed case reports of functional activity in the three limb-girdle type 2E subjects given a 5x1013vg/kg dose of MYO-101/SRP-9003, having in February unveiled evidence of increased beta-sarcoglycan expression and reduction in creatinine kinase – findings backing the project’s mechanism. Sarepta today said measures like subjects’ time to rise and 100m-walk test improved by 0.3-0.9 and 1.3-10.9 seconds respectively at day 270. Of course there was no comparator, so the relative benefit can only be guessed at. Sarepta provided age-matched historical controls suggesting that these measures would normally decline from baseline, and argued that it was seeing “dramatic” evidence of improvement. Only a controlled trial will actually show this; the group says three more subjects will be enrolled at a fourfold higher dose, at which point three control patients will also be recruited, before an optimal dose for a registrational study will be selected.