Sarepta’s Gene Therapy Crisis Deepens — This Week in Biotech #62
FDA setbacks, insider buys, trial wins, and pipeline pivots (July 18–24, 2025).
Hi and welcome to This Week in Biotech by Biotech Blueprint, edition 62, covering biotech & pharma news from July 18th to July 24th, 2025.
This week, Biotech Blueprint turned one year old! 🥳 Thanks for following along, sharing, and making this such a fun ride.
🎙️ Biotech Blueprint brings you weekly video updates on the latest biotech and pharma news, plus in-depth podcast interviews with industry leaders. You can find us on YouTube, Spotify, and Apple Podcasts.
In the last episode, I teamed up with the Biotech Capital Compass to explore the current state of gene editing. We dug into CRISPR’s first FDA approval, the regulatory frameworks shaping the field, and why delivery, durability, and manufacturing still stand between promising science and scalable medicine. It’s part 1 of a new series on gene therapies, told from both a scientific and investment perspective.
THIS WEEK IN BIOTECH VIDEO SUMMARY
THIS WEEK’S KEY TAKEAWAYS 🔑
▪️ Sarepta’s gene therapy unraveling is this week’s most consequential story. With a third patient death, FDA clinical holds, and the voluntary halt of Elevidys shipments both in the US and abroad, Sarepta’s once-flagship AAV platform is in crisis. The fallout will ripple across the gene therapy landscape, especially for non-ambulatory Duchenne patients who now face dwindling options.
▪️ Insiders are buying biotech again, or at least Simeon George is. His $51.5M purchase of CRISPR Therapeutics shares is one of the largest recent insider buys across the sector, signaling confidence as the company heads into Q2 earnings.
▪️ Abivax delivered a rare phase 3 win in ulcerative colitis. Obefazimod posted solid week 8 remission data across two large pivotal trials, a notable feat in a tough indication, especially for patients with prior JAK failure. Shares rallied 400%.
▪️ Rocket Pharmaceuticals is tightening its focus. The company is cutting 30% of staff and shelving some programs to concentrate on its AAV cardiovascular gene therapies, a move that extends its runway into 2027 but underscores the capital discipline required in today’s market.
▪️ Replimune’s RP1 rejection stunned investors. A surprise CRL wiped out 77% of the company’s value, with the FDA citing trial design flaws in a program once considered on the fast track. A bounce the next day offered little reassurance of a quick path forward.
▪️ Darzalex’s EU approval in smouldering multiple myeloma is more than a regulatory milestone, it’s a paradigm shift for early-stage treatment and could reshape clinical expectations globally.
▪️ M&A watch: Bavarian Nordic confirmed buyout talks with Nordic Capital and Permira. While no bid is on the table yet, the sharp share move suggests investors are betting on a deal.
▪️ New leadership at CDER: The FDA’s appointment of George Tidmarsh signals potential shifts ahead in drug approval philosophy.
MARKET UPDATES
🔹 CRISPR Therapeutics jumped nearly 20% Friday after board director Simeon George disclosed a $51.5M insider buy at $52.03 per share, one of biotech’s largest recent insider purchases. The stock is now up 58% YTD, boosted by optimism ahead of Q2 earnings and momentum from its approved sickle cell therapy with Vertex.
🔹 Atara Biotherapeutics rose 13% after Panacea Innovation, a major shareholder, bought 19K shares worth ~$186K. The investment comes despite recent regulatory setbacks, including an FDA rejection and clinical holds. Shares are up 25% over the past year.
BIOTECH/PHARMA NEWS 🧬
🔹 Sarepta’s gene‑therapy crisis escalates: Last week, the company confirmed a third patient death linked to its AAV-based platform, this time in a limb‑girdle muscular dystrophy (LGMD) trial due to acute liver failure. In response, the FDA requested a voluntary halt to shipments of Elevidys, Sarepta’s approved Duchenne muscular dystrophy therapy. The company initially resisted, citing no new safety signals in ambulatory patients, but ultimately paused all U.S. shipments to comply. At the same time, it agreed to update Elevidys’ labeling with a black box warning and explore enhanced immunosuppression protocols. In parallel, the FDA placed a clinical hold on Sarepta’s four LGMD gene therapy trials, including the lead candidate SRP‑9003, while stripping the company of its AAVrh74 platform designation.
Meanwhile, Roche, which markets Elevidys outside the U.S., voluntarily paused new international shipments in jurisdictions that rely on FDA approval, such as Japan and the UAE. For now, Roche says it will continue supplying ambulatory patients in countries where it has independent approval, pending regulatory dialogue.
On Tuesday, STAT reported that FDA reapproval could hinge on Sarepta demonstrating that such safety issues can be fully mitigated. Then on Thursday, Endpoints added that the FDA will likely require new studies before Elevidys can return to market. Citing a senior agency official, the report described a unanimous view within the FDA’s biologics division that the current safety profile does not support reintroduction. The exact nature of the required studies remains unclear, but Sarepta faces a long and uncertain path forward. In parallel, Roche has paused new international shipments in countries that defer to FDA decisions, though it continues distribution in independently approved markets.
While analysts criticized Sarepta’s delayed disclosure, many acknowledge the tragic stakes for Duchenne and LGMD patients who have few treatment options. Sarepta has long been praised for its community engagement, but the crisis reveals the painful tension between urgency and oversight. Shares fell more than 29%, and some brokerages, including H.C. Wainwright, cut their price target to $0, warning the company’s viability is at risk. I believe recovery is possible, but it now depends on whether it can meet FDA expectations, restart clinical development, and regain investor and patient trust in its therapy pipeline.
🔹 Rocket Pharmaceuticals is streamlining operations to focus on its adeno-associated virus (AAV) cardiovascular pipeline, which includes gene therapies for Danon disease, PKP2-associated arrhythmogenic cardiomyopathy, and BAG3-related dilated cardiomyopathy. As part of this shift, the company is implementing a 30% headcount reduction and other cost-saving measures, aiming to cut operating expenses by roughly 25% over the next year. Rocket is also prioritizing regulatory follow-up for Kresladi, its treatment for severe LAD-I, while deprioritizing Fanconi Anemia and PKD programs, pushing anticipated approval timelines beyond 2026. The reorganization is expected to extend Rocket’s cash runway into Q2 2027 and reflects a sharpened focus on the most commercially and clinically promising programs in its pipeline.
🔹 Danish vaccine maker Bavarian Nordic announced it's in early discussions with private equity firms Nordic Capital and Permira over a potential acquisition. While no formal bid has been made, the news sent shares soaring over 20% in Thursday trading. The company, best known for its mpox vaccine Jynneos, emphasized that talks are ongoing and there’s no guarantee a deal will materialize or what terms it might involve. Bavarian Nordic’s market cap stood at ~$2.9B as of market close. The stock had recently dipped, but analysts like Myriam Alvarez have called its valuation attractive, upgrading it to Strong Buy back in April.
🔹 The European Commission has approved J&J’s Darzalex as the first authorized treatment for patients with high-risk smouldering multiple myeloma. The approval is based on phase 3 AQUILA trial data showing the subcutaneous therapy cut the risk of disease progression or death by 51% compared to active monitoring. The milestone shifts the treatment paradigm for this early-stage, asymptomatic form of myeloma, offering a proactive option for patients previously left with watchful waiting.
🔹 RFK Jr. signed off on a recommendation to remove thimerosal from all influenza vaccines. Thimerosal, a mercury-based preservative used in multidose vials, has been largely phased out in the U.S. and is not linked to harm, according to decades of scientific research. The CDC reports that 96% of flu shots for the 2024-2025 season are already thimerosal-free. Still, critics warn the move could increase costs and reduce vaccine access globally, especially in lower-income countries where single-dose alternatives are limited.
🔹 Replimune received a surprise Complete Response Letter from the FDA rejecting its Biologics License Application for RP1 in advanced melanoma. The agency said the mid-stage IGNYTE trial lacked sufficient control and clarity, and raised concerns about trial heterogeneity and study design, though no safety issues were cited. Replimune plans to request a Type A meeting to determine next steps. The rejection stunned analysts, who had expected approval following RP1’s breakthrough designation and priority review. Shares plummeted 77%, with some analysts now projecting delays into 2030 and potential company restructuring. Still, shares climbed 30% the next day, likely driven by bargain hunting or short covering.
🔹 The FDA has named biotech executive and Stanford pediatric oncologist George Tidmarsh as the new head of its Center for Drug Evaluation and Research (CDER). The appointment, made by FDA Commissioner Marty Makary, comes at a politically sensitive time as RFK Jr. pushes for more regulatory scrutiny, including a crackdown on direct-to-consumer drug advertising. Tidmarsh brings decades of experience from both academia and industry, having led multiple biotech companies and contributed to several drug approvals. His track record has reassured some investors. Still, hd has voiced strong views about scientific groupthink, FDA inconsistency, and the need to root out fraud in academic research. His leadership could shape key debates ahead, including accelerated approvals, off-label communication, and broader pharma oversight under a reform-minded administration.
🔹 Moderna has officially shelved plans to build an mRNA manufacturing facility in Japan, pointing to worsening business conditions both domestically and globally. While the company completed an mRNA R&D hub in Kanagawa Prefecture, it paused its larger manufacturing ambitions, citing soft COVID-19 vaccine demand, sluggish RSV vaccine uptake, and growing geopolitical uncertainty. With U.S. trade tensions flaring and the prospect of pharmaceutical tariffs on the horizon, Moderna says it will revisit expansion plans only if the policy and commercial climate improves.
CLINICAL TRIAL UPDATES 📊
🔹 Abivax announced that its lead asset, obefazimod, achieved statistically significant clinical remission at week 8 in both phase 3 ABTECT-1 and ABTECT-2 trials in moderate-to-severe ulcerative colitis. The 50 mg dose delivered a pooled 16.4% placebo-adjusted remission rate, with all key secondary endpoints met. The trials enrolled over 1,200 patients, including a large population with prior JAK inhibitor failure. Obefazimod was well tolerated, with no new safety signals. Subject to positive maintenance data in 2026, Abivax plans to file for FDA and EMA approval. The news sent shares soaring 400%.
🔹 Roche reported mixed results for astegolimab in COPD: the phase 2b ALIENTO trial showed a significant 15.4% reduction in exacerbations, but the larger phase 3 ARNASA study missed its primary endpoint. Both trials included broad COPD populations and showed a consistent safety profile. The results add to growing skepticism around IL-33 as a target. Roche’s setback follows Sanofi and Regeneron’s failure with itepekimab, suggesting IL-33 inhibition may not offer consistent benefit across COPD’s heterogeneous patient groups.
AI SUMMARY 🎙️
Listen to an AI-generated summary of this episode below.
ON THE HORIZON 🔭
🔹 July 2025 FDA PDUFAs:
July 10: Regeneron’s Lynozyfic ✅ APPROVED
July 22: Replimune Group Inc.’s Vusolimogene oderparepvec for advanced melanoma. ❌ REJECTED
July 23: GSK’s Blenrep for the treatment of relapsed/refractory multiple myeloma. 🕓︎ DELAYED (new PDUFA is 10/25/25)
July 27: Royalty Pharma’s aficamten for the treatment of obstructive hypertrophic cardiomyopathy.
July 28: Apellis Pharmaceuticals’ Pegcetacoplan for kidney disease.
July 29: PTC Therapeutics’ Sepiapterin for phenylketonuria.
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DISCLOSURE: I have no business relationships with any company mentioned in this article.