$RGNX

@adamfeuersteinMay 14, 2026 · 11:07 AM

$RGNX Duchenne gene therapy study results are out: microdystrophin expression reached an average of 71% of normal across all 31 boys at 12 wks. Functional improvements in a subset of boys followed for one year also seen. The big question remains: Will the FDA still follow the $SRPT precedent and grant accelerated approval to the Regenxbio gene therapy? CEO Curran Simpson told me the company is holding off on submitting to the FDA until early next year. “I think our data checks every single box that you would want for accelerated approval,” he told me. "We’re not in a rush to go to the FDA at this point. We want to give time for the leadership changes to occur. But that’s OK, because we can still meet our timeline of securing an approval in 2027." More details in our story, written with @Jasonmmast in the following post.

@adamfeuersteinMar 19, 2026 · 7:20 PM

This week's Biotech Scorecard newsletter: Six drugmakers, six months: Charting the FDA’s course in the post-Prasad era $REPL Pierre Fabre $ATRA $QURE $CAPR $RGNX https://t.co/sGa7G6YTDn

@adamfeuersteinFeb 26, 2026 · 4:34 PM

(Hopefully) Final word today on the Makary $QURE (or was it $RGNX) thing: Bottom line: Makary shouldn't be talking publicly about unresolved drug applications. Uniqure doesn't even have an application submitted; and RegenxBio's CRL letter isn't posted to the FDA's web site. Also, does Makary even know what the hell he's talking about? "...there was a product where the researchers drilled a burr hole, literally a hole in people's skulls..." That's Uniqure, clearly. But... "...inject intrathecally into the ventricle..." could be RegenxBio, which is injected into the spine. Is Makary conflating two different therapies? Total shitshow...

@adamfeuersteinFeb 26, 2026 · 2:46 PM

@BiotechAnalysst $RGNX therapy is delivered intrathecally into the spine, not via a burr hole in the head like $QURE

@adamfeuersteinFeb 18, 2026 · 5:07 PM

"Prasad" stocks today: $CAPR +11%, $REPL +11%, $QURE +9%. $RGNX $SLDB up, too

@adamfeuersteinFeb 12, 2026 · 3:08 PM

This week's Biotech Scorecard newsletter: The old Vinay Prasad never left. He just changed jobs Submissions to the FDA are handled by teams of reviewers, of course. But when I look across all of these recent cases, I see a consistent throwback to the old Prasad — questioning the legitimacy of biomarkers, surrogate endpoints, and single-arm clinical trials, even in the setting of rare diseases. In some of these rare-disease drug rejections, Atara $ATRA and Regenxbio $RGNX are good examples, Prasad or the staffers he directs aren’t following the agency’s own guidance. Companies are told early that their clinical development programs meet FDA requirements, but then, almost arbitrarily, the FDA changes the rules. Uniqure $QURE and its gene therapy for Huntington’s disease have been in a holding pattern for months because guidance it received long ago from the FDA is now, under Prasad’s watch, null and void. Read more at link below...

@adamfeuersteinFeb 9, 2026 · 9:26 PM

FDA rejects Regenxbio’s $RGNX rare-disease gene therapy Agency raised questions about the surrogate biomarker used to predict clinical benefit in Hunter syndrome https://t.co/LZSIHMMe73

@adamfeuersteinFeb 9, 2026 · 9:12 PM

$RGNX Hunter syndrome gene therapy rejected by FDA

@adamfeuersteinJan 28, 2026 · 12:45 PM

$RGNX A question that is likely to come up today -- How different or similar are the MPS gene therapies to RGX-202, its gene therapy for DMD? I asked the company: "RGX-202 which is in pivotal study for Duchenne is a completely different therapy than either RGX-121 or RGX-111. RGX-202 uses systemic delivery of a novel construct that includes the AAV8 vector, a microdystrophin with the CT domain, and different promoter. We have seen no SAEs or AESIs in the Phase I/II trial of RGX-202. RGX-121 and RGX-111 use AAV9."

@adamfeuersteinJan 28, 2026 · 12:33 PM

BREAKING: FDA halts $RGNX gene therapy trials after brain tumor found in patient. Tumor found in patient treated with MPS I therapy. FDA placed hold on it and the MPS II therapy. They are similar constructs. The MPS II therapy has a Feb. 8 PDUFA date, now up in the air. https://t.co/oU23gsA5G2 via @Jasonmmast

@adamfeuersteinJan 12, 2026 · 5:07 PM

$SRPT Elevidys Q4 sales $110M vs consensus $120M At his #JPM26 presentation, CEO Doug Ingram notes 80% of addressable ambulatory DMD patients remain untreated. He sees this a huge opportunity for Elevidys, but I will note it's also the same for $SLDB and $RGNX and others developing next-gen gene therapies.

@adamfeuersteinOct 8, 2025 · 4:06 PM

Duchenne gene therapy stocks today: $SLDB +22% $RGNX +14% $SRPT +1%