Pharma BD Deal Intelligence
Bayer and Mammoth Biosciences entered a strategic collaboration and option agreement leveraging Mammoth's ultra-small Cas enzymes (Cas14, Cas-phi) for in vivo gene-editing therapies across five preselected indications. Mammoth received $40M upfront and is eligible for option exercise fees plus over $1B in milestones. Review (June 2026): no primary source indicates the collaboration has closed or terminated; as of 2025 Mammoth still listed Bayer among its active partnerships (alongside Vertex and Regeneron). The underlying ultracompact platform has advanced materially since signing — Mammoth reported new NanoCas extrahepatic-editor results (Jan 2025) and nominated its first development candidate, MB-111, a CasPhi-based, LNP-delivered in vivo liver editor targeting APOC3 for persistent chylomicronemia, with preclinical data at ESGCT (Oct 2025) and a planned clinic entry in 2026 — reinforcing the deal's ultra-compact / liver-targeted thesis. (MB-111 is not attributed by Mammoth to the Bayer collaboration specifically.)