FDA Drama & Psychedelic Setback — This Week in Biotech #58
FDA turmoil impacts key drug decisions, Compass’s phase 3 psilocybin data spooks investors, and Exelixis soars on cancer results (June 20–26, 2025).
Hi and welcome to This Week in Biotech by Biotech Blueprint, edition 58, covering biotech & pharma news from June 20th to 26th, 2025.
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THIS WEEK IN BIOTECH VIDEO SUMMARY
THIS WEEK’S KEY TAKEAWAYS 🔑
This week in biotech was marked by significant clinical trial results and ongoing regulatory drama. Internal FDA conflicts reportedly delayed an approval decision for KalVista’s oral HAE therapy and led to the cancellation of an advisory committee meeting for Capricor’s Duchenne treatment, raising questions about the agency's review processes.
On the clinical front, the sector saw both wins and setbacks. Compass Pathways’ stock plummeted despite achieving a historic first ever positive phase 3 result for a psychedelic (psilocybin) in treatment-resistant depression, as the efficacy margin fell short of investor hopes. Similarly, Altimmune’s shares tumbled over concerns about a lack of fibrosis improvement in its MASH trial, even as it met its primary endpoint for disease resolution. In contrast, Exelixis surged on positive overall survival data in colorectal cancer, and Cidara more than doubled after its long-acting flu preventative showed high efficacy. Sangamo also saw a significant boost from promising one year data for its Fabry disease gene therapy.
In other major news, Amgen’s monthly obesity candidate, MariTide, delivered strong phase 2 weight loss data but failed to excite investors in a competitive market. Kymera Therapeutics provided a mixed update, discontinuing one partnered drug with Sanofi while advancing another and launching a new collaboration with Gilead.
Lastly, the new CDC vaccine advisory committee voted to recommend that all future flu vaccines be thimerosal-free, following a controversial meeting. Meanwhile, President Trump’s nominee for CDC director, Susan Monarez, publicly distanced herself from anti-vaccine sentiments, affirming her support for vaccines as “life-saving.”
BIOTECH/PHARMA NEWS 🧬
🔹 KalVista’s bid to bring the first oral on-demand therapy for hereditary angioedema (HAE) to market hit a snag this month. The FDA missed its June 17 approval deadline for sebetralstat, citing a “heavy workload and limited resources.” The company emphasized that no additional data were requested, and the only item under review remains final labeling. But behind the scenes, the delay has sparked controversy. According to Endpoints News, FDA Commissioner Marty Makary reportedly pushed for a last-minute rejection, an effort that was ultimately blocked by internal scientific staff over legal concerns. Despite the setback, KalVista maintains confidence in near-term approval.
🔹 Capricor Therapeutics’ shares fell 32% Friday following reports that an FDA advisory committee meeting to review its lead Duchenne muscular dystrophy (DMD) therapy, Deramiocel, was abruptly canceled. STAT News reported that the cancellation came after a clash between Nicole Verdun, then-director of the FDA’s cell and gene therapy division, and her superior, CBER head Dr. Vinay Prasad, who was skeptical of Deramiocel’s safety and efficacy. Verdun was subsequently placed on leave. Despite the disruption, Capricor released promising four-year data from its HOPE-2 extension study showing that Deramiocel slowed skeletal muscle decline and preserved cardiac function in DMD patients, while maintaining a strong safety profile. The company emphasized continued engagement with the FDA and is still preparing for a potential advisory meeting in late July.
🔹 Kymera Therapeutics shared mixed updates on its protein degrader partnerships. In their partnership with Sanofi, they will discontinue development of KT-474, an IRAK4 degrader in phase 2 trials for atopic dermatitis, but they will advance a next-generation candidate, KT-485, which showed improved preclinical data. Kymera also announced a new collaboration with Gilead to develop an oral CDK2-targeting molecular glue degrader for breast and other solid tumors. Gilead will pay $85M upfront in a deal with a total value of $750M in milestone payments.
CLINICAL TRIAL UPDATES 📊
🔹 CRISPR Therapeutics released encouraging phase 1 data for CTX310, its in vivo gene-editing therapy targeting ANGPTL3. The therapy achieved up to 82% and 86% reductions in triglycerides and LDL, respectively, with no significant liver toxicity and a clean safety profile. However, investors were less enthused by a delay in the CTX320 readout, the company’s second in vivo candidate targeting Lp(a), a major cardiovascular risk factor. CRISPR had initially promised data in Q2 2025, but now expects it in the first half of 2026, citing a strategic decision to integrate insights from the evolving Lp(a) treatment landscape.
🔹 Despite achieving its primary endpoint in the phase 2b IMPACT trial, demonstrating MASH resolution rates of 59.1% and 52.1% at 24 weeks and significant weight loss with excellent tolerability, Altimmune’s shares dropped sharply in pre-market trading, falling around 60–64%. The steep decline reflects investor concern over the trial’s lack of statistically significant fibrosis improvement, even though a supplemental AI analysis showed promising reductions in fibrosis in over 30% of patients.
🔹 In its phase 1/2 ARROS-1 trial, Nuvalent’s ROS1-selective inhibitor zidesamtinib showed a 44% response rate in 117 ROS1 TKI-pretreated NSCLC patients, with durable responses (78% at 12 months) and intracranial activity, even in those with resistance mutations. In patients who received only one prior TKI, the response rate rose to 51%, with 93% maintaining response at 12 and 18 months. Safety was favorable with low discontinuation (2%) and dose reduction (10%) rates. Nuvalent plans to begin a rolling NDA submission in July 2025.
🔹 Sangamo Therapeutics rose 13% after reporting positive topline results from its phase 1/2 STAAR study evaluating ST-920, a one-time gene therapy for Fabry disease. At 52 weeks, patients given a single dose maintained kidney function, with an average eGFR increase of 1.97 mL/min/1.73m² per year, compared to declines typically seen with existing treatments like Fabrazyme and Galafold. The FDA has agreed this eGFR slope can serve as the basis for accelerated approval, and all patients previously on enzyme replacement therapy were successfully withdrawn and remain off treatment. ST-920 also showed improvements in quality of life and disease severity scores, and no new safety concerns were identified. Sangamo plans to file a BLA in early 2026 and is seeking a commercial partner.
🔹 Cidara Therapeutics more than doubled in value after reporting positive topline results from its phase 2b trial of CD388, a long-acting, non-vaccine biologic for seasonal influenza. A single dose provided 76%, 61%, and 58% protection at 450mg, 300mg, and 150mg doses, respectively, over 24 weeks, surpassing expectations in a trial of over 5,000 unvaccinated adults. CD388 met all primary and secondary endpoints and showed no safety concerns, with tolerability comparable to placebo. Unlike traditional vaccines, CD388’s drug-Fc conjugate design doesn’t rely on immune activation, potentially making it ideal for immunocompromised individuals.
🔹 Amgen’s MariTide showed strong phase 2 obesity data, but investors remain cautious. Amgen unveiled full results from its phase 2 trial of MariTide, a monthly GLP-1/GIPR therapy for obesity. The drug delivered up to ~20% average weight loss at 52 weeks in people without Type 2 diabetes, and ~17% in those with diabetes, without hitting a weight-loss plateau. It also drove meaningful improvements in HbA1c, blood pressure, lipids, and inflammation markers. Tolerability was in line with the GLP-1 class. Despite no new safety signals and the potential convenience of monthly dosing, Amgen shares fell, as investors weighed the data against entrenched competition from Eli Lilly and Novo Nordisk.
🔹 Compass Pathways shares plunged over 45% on Monday despite hitting the primary endpoint in its phase 3 trial of psilocybin therapy COMP360 for treatment-resistant depression. The COMP005 study showed a statistically significant improvement on the MADRS scale versus placebo, marking the first ever positive phase 3 readout for a classic psychedelic. Still, the result fell short of investor expectations for a 4-5 point margin, fueling skepticism about commercial viability. Broader sentiment toward the psychedelic sector also took a hit: atai Life Sciences dropped ~15%, MindMed fell ~6%, and Cybin and GH Research each slid ~5%. Compass’s next major data readout isn’t expected until 2026, and with regulatory timelines still uncertain, the path to market for psychedelics remains clouded.
🔹 Exelixis announced positive phase 3 results from its STELLAR-303 trial, showing that zanzalintinib combined with Roche’s Tecentriq, significantly improved overall survival compared to Bayer’s Stivarga in patients with previously treated non-MSI-high metastatic colorectal cancer. The results triggered a 12% surge in Exelixis stock and renewed investor confidence in zanzalintinib’s blockbuster potential as analysts project up to $5B in annual sales by 2033. With no new safety issues reported and regulatory discussions ahead, zanzalintinib is now positioned to reshape the colorectal cancer treatment landscape.
PUBLIC HEALTH SPOTLIGHT 🦠
🔹 Tensions escalated at Thursday’s CDC vaccine advisory committee meeting as former Children’s Health Defense leader Lyn Redwood presented on thimerosal, a mercury-based preservative that has not been used in most vaccines for decades, and labeled it as a neurotoxin. The CDC’s own presentation debunking any link between thimerosal and autism was pulled from the agenda. Despite the controversy, the committee voted to recommend that all flu vaccines going forward should be thimerosal-free, including those for children, pregnant women, and adults.
🔹 Susan Monarez, President Trump’s nominee to lead the CDC, told the Senate on Wednesday that she has seen no evidence linking vaccines to autism, distancing herself from views held by her would-be boss, HHS Secretary RFK Jr. Monarez, currently acting CDC director, emphasized her support for vaccines as “life-saving” and said she would prioritize access and outbreak preparedness if confirmed. Her comments come amid upheaval at the CDC’s vaccine advisory panel, which Kennedy recently reshaped with members skeptical of U.S. vaccine policy. Despite concerns from some lawmakers, Monarez is expected to win Senate confirmation.
AI SUMMARY 🎙️
Listen to an AI-generated summary of this episode below.
ON THE HORIZON 🔭
🔹 June 2025 FDA PDUFAs:
June 10: Merck’s BLA for clesrovimab. ✅ APPROVED
June 12: UroGen’s UGN-102. ✅ APPROVED
June 17: KalVista’s sebetralstat. ⏳ DELAYED to ~mid-July
June 19: Gilead’s lenacapavir. ✅ APPROVED
June 23: Nuvation Bio’s taletrectinib.
June 28: Unicycive’s oxylanthanum carbonate.
June 30: Verastem’s avutometinib + defactinib combo.
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DISCLOSURE: I have no business relationships with any company mentioned in this article.