At a Glance
- Company: Astellas Pharma
- Actions: Halt AT132, drop ASP5502/ASP1570
- Cost: 16.4B yen (~$103M) impairment
- Replacement: ASP2957 (Phase 1/2)
- Next steps: Dyno capsid partnership
What happened?
Astellas Pharma announced on 27 April 2026 it halted development of AT132 (resamirigene bilparvovec) gene therapy for X-linked myotubular myopathy (XLMTM) and terminated Phase 1 trials of ASP5502 (STING inhibitor for Sjögren’s) and ASP1570 (cancer candidate). The moves incur a 16.4 billion yen (~$103M) impairment.
Why does it matter?
AT132’s history of safety issues (4 patient deaths from liver failure, FDA hold) prompted the pivot to ASP2957, which uses a muscle-specific AAV capsid enabling 100-fold lower dosing with reduced liver targeting. Reflects Astellas’ focus on promising assets amid pipeline prioritisation.
Who’s behind it?
AT132 originated from 2019’s $3B Audentes acquisition. ASP2957 licensed from Kate Therapeutics (2023, later Novartis-acquired). CEO Naoki Okamura emphasised resource allocation to high-potential programmes.
How was it achieved?
Preclinical data favoured ASP2957’s superior muscle tropism. AT132 long-term follow-up continues for enrolled patients. Terminations of ASP5502/ASP1570 were business decisions, not safety-related.
What’s next?
Advance ASP2957 in Phase 1/2 enrolment; leverage recent $15M Dyno Therapeutics deal for optimised muscle AAVs. Continue ASPIRO trial data readouts.
What are people saying?
Naoki Okamura, CEO: “ASP2957 enables clinical study… 100-fold lower than AT132… focus on ASP2957 development.” Astellas spokesperson: “Impairment not due to safety… complete 5-year follow-up.”