This week’s Rare Diseases update highlights regulatory progress, orphan designations, acquisition activity, safety scrutiny, and mixed clinical data across emerging therapies.
In Today’s Newsletter
Dive deeper
💉 HYMPAVZI EC approval in hemophilia with inhibitors [1] [EU • 13 May 2026]
https://www.pfizer.com/news/press-release/press-release-detail/european-commission-approves-pfizers-hympavzi-treatment
Context: HYMPAVZI (marstacimab; Pfizer) is a once-weekly subcutaneous therapy for hemophilia A or B.
Key point: The EC expanded approval to patients 12+ and ≥35 kg with hemophilia A or B with inhibitors.
Implication: May influence prescriber choice and payer reviews pending full data.
🧬 Asedebart Japan orphan drug designation [2] [Japan • 18 May 2026]
https://news.cision.com/h–lundbeck-a-s/r/lundbeck-receives-orphan-drug-designation-in-japan-for-asedebart-for-the-treatment-of-patients-with-,c4349497
Context: Asedebart (Lu AG13909; Lundbeck) is an investigational anti-ACTH monoclonal antibody.
Key point: Japan’s MHLW granted orphan drug designation for CAH and Cushing’s disease.
Implication: Signals pipeline investment and modality expansion.
🤝 Neurocrine completes Soleno acquisition [3] [US • 18 May 2026]
https://neurocrine.gcs-web.com/news-releases/news-release-details/neurocrine-biosciences-completes-acquisition-soleno-therapeutics
Context: Neurocrine acquired Soleno, adding VYKAT XR (diazoxide choline) for Prader-Willi syndrome hyperphagia.
Key point: The $2.9 billion transaction closed, and Soleno became a Neurocrine subsidiary.
Implication: Signals pipeline investment and modality expansion.
⚠️ Tavneos safety concerns in Japan [4] [Japan • 18 May 2026]
https://www.biospace.com/business/amgens-rare-disease-drug-tavneos-tied-to-20-deaths-in-japan
Context: Tavneos (avacopan; Amgen/Kissei) is used in autoimmune rare disease settings.
Key point: BioSpace reported 20 deaths in Japan after launch, with many linked to VBS/DILI and causality not fully determined.
Implication: May affect prescriber confidence, monitoring, and regulatory scrutiny.
🫁 Efdoralprin alfa Phase 2 AATD data [5] [US • 18 May 2026]
https://www.sanofi.com/en/media-room/press-releases/2026/2026-05-18-19-30-00-3296985
Context: ElevAATe Phase 2 studied efdoralprin alfa (Sanofi) in AATD-related emphysema.
Key point: The recombinant therapy was superior to standard-of-care augmentation therapy on fAAT levels.
Implication: May influence prescriber choice and payer reviews pending full data.
🩸 Zovegalisib Phase 2 vascular anomalies data [6] [19 May 2026]
https://www.fiercebiotech.com/biotech/relay-full-steam-ahead-pi3k-inhibitor-fueled-first-data-blood-vessel-disorders
Context: Zovegalisib (Relay Therapeutics) is a PI3Kα inhibitor in PIK3CA-driven vascular anomalies.
Key point: Early Phase 2 data showed lesion responses and symptom improvements in assessed patients.
Implication: May influence prescriber choice and payer reviews pending full data.
📉 BMN 401 Phase 3 ENPP1 miss [7] [19 May 2026]
https://www.biospace.com/drug-development/biomarin-suffers-another-blow-to-rare-disease-portfolio-in-phase-3-flop
Context: BMN 401 (BioMarin) is an investigational enzyme replacement therapy for ENPP1 deficiency.
Key point: Phase 3 showed biomarker improvement but missed clinical endpoints, including rickets-related measures.
Implication: May affect regulatory strategy and confidence in the program.
🧫 EN001 Phase 2a first dose in CMT1A [8] [Korea • 19 May 2026]
https://www.thebionews.net/news/articleViewAmp.html?idxno=24694
Context: EN001 (ENCell) is an allogeneic umbilical cord-derived MSC therapy for CMT1A.
Key point: ENCell dosed the first patient in a 21-patient Phase 2a trial across Korean university hospitals.
Implication: May influence prescriber choice and payer reviews pending full data.
Why it matters
- Rare disease approvals and designations remain concentrated around high-unmet-need indications with limited treatment options.
- Regulatory momentum is mixed, with Pfizer and Lundbeck advancing while BioMarin faces clinical translation risk.
- Safety signals remain a major commercial and regulatory risk, as shown by Tavneos scrutiny in Japan and the US.
- BD continues to reshape rare disease portfolios, with Neurocrine adding a recently launched Prader-Willi syndrome therapy.
- Cell, antibody, recombinant protein, and targeted small-molecule approaches all featured in this week’s pipeline updates.
📚 View the full Rare Disease archive on our research hub page
🚀 Accelerate your success. Contact us now
📂 Explore our case studies. See examples of our work.
💡 Read our insights. Learn from our latest reports and analysis
🧰 See our full range of services. Discover how we can help you.
🎯 Catch up on the Top Rare Disease news from the past two weeks, curated by the LucidQuest team.
FAQ
What changed for HYMPAVZI in the EU?
The EC expanded HYMPAVZI’s label to hemophilia A or B patients 12+ with inhibitors and body weight ≥35 kg. Pfizer cited Phase 3 BASIS data. [1]
Is asedebart approved in Japan?
No. Asedebart received orphan drug designation in Japan for CAH and Cushing’s disease. Lundbeck states efficacy and safety are not established. [2]
What did Neurocrine gain from buying Soleno?
Neurocrine added VYKAT XR, described by the company as the first and only approved medicine for hyperphagia in Prader-Willi syndrome. [3]
What is the Tavneos concern in Japan?
BioSpace reported 20 deaths among Tavneos-treated patients in Japan since launch, many linked to VBS/DILI. Amgen said causality could not be determined in some cases. [4]
Did BioMarin’s BMN 401 Phase 3 succeed?
Not clinically. BMN 401 improved a biomarker but missed the RGI-C clinical endpoint and key secondary endpoints in ENPP1 deficiency. [7]
What is ENCell testing with EN001?
ENCell is testing repeated EN001 dosing in CMT1A patients in a Phase 2a placebo-controlled study, with CMT neuropathy score change at 24 weeks as the primary endpoint. [8]
Entities / Keywords
Pfizer, HYMPAVZI, marstacimab, hemophilia A, hemophilia B, inhibitors, BASIS
Lundbeck, asedebart, Lu AG13909, anti-ACTH, CAH, congenital adrenal hyperplasia, Cushing’s disease
Neurocrine Biosciences, Soleno Therapeutics, VYKAT XR, diazoxide choline, Prader-Willi syndrome, hyperphagia
Amgen, Kissei Pharmaceutical, Tavneos, avacopan, VBS, vanishing bile duct syndrome, DILI
Sanofi, efdoralprin alfa, ElevAATe, AATD, alpha-1 antitrypsin deficiency, fAAT
Relay Therapeutics, zovegalisib, PI3Kα, PIK3CA-driven vascular anomalies
BioMarin, BMN 401, ENPP1 deficiency, ENERGY 3, RGI-C, rickets
ENCell, EN001, CMT1A, Charcot-Marie-Tooth disease, MSC therapy, ENCT
References
- https://www.pfizer.com/news/press-release/press-release-detail/european-commission-approves-pfizers-hympavzi-treatment
- https://news.cision.com/h–lundbeck-a-s/r/lundbeck-receives-orphan-drug-designation-in-japan-for-asedebart-for-the-treatment-of-patients-with-,c4349497
- https://neurocrine.gcs-web.com/news-releases/news-release-details/neurocrine-biosciences-completes-acquisition-soleno-therapeutics
- https://www.biospace.com/business/amgens-rare-disease-drug-tavneos-tied-to-20-deaths-in-japan
- https://www.sanofi.com/en/media-room/press-releases/2026/2026-05-18-19-30-00-3296985
- https://www.fiercebiotech.com/biotech/relay-full-steam-ahead-pi3k-inhibitor-fueled-first-data-blood-vessel-disorders
- https://www.biospace.com/drug-development/biomarin-suffers-another-blow-to-rare-disease-portfolio-in-phase-3-flop
- https://www.thebionews.net/news/articleViewAmp.html?idxno=24694