Mereo BioPharma Licenses Alvelestat to Sentynl in Deal Worth Up to $475 Million
The biopharmaceutical company secured a U.S. partnership for its alvelestat program that could yield $40 million upfront and up to $435 million in milestones.
Mereo BioPharma Group (MREO) entered into an option and license agreement with Sentynl Therapeutics for alvelestat, its treatment for alpha-1 antitrypsin deficiency-associated lung disease, granting Sentynl exclusive U.S. commercial rights and global manufacturing rights. The deal marks a strategic pivot for Mereo, which had previously been developing the asset internally with no disclosed commercial partner for the AATD-LD indication.
Under the terms, Mereo is eligible to receive a non-refundable option fee, $40 million in upfront and research-and-development payments upon option exercise, and up to $435 million in regulatory and commercial milestone payments. The company would also collect double-digit tiered royalties on U.S. net sales, creating a new potential revenue stream for a pipeline that had not carried a disclosed commercial partner in prior quarters.
Mereo retains rest-of-world commercial rights to alvelestat, preserving the option to develop and market the therapy outside the United States independently or through additional partnerships. The structure allows the company to monetize the U.S. opportunity while maintaining exposure to international markets.
A Phase 3 development program for alvelestat could be initiated in early 2027, with Sentynl funding the program upon exercise of the option. During a short option period, the two companies plan to collaborate on refining the Phase 3 trial design.
The partnership reshapes Mereo's pipeline description, with alvelestat now characterized by the Sentynl option-and-license arrangement rather than as a wholly internal program. The shift reflects a broader trend among smaller biopharmaceutical companies to partner late-stage assets with commercial-stage organizations to share development costs and secure commercialization infrastructure.
For Mereo, the deal provides non-dilutive capital and a funded path to late-stage clinical development without bearing the full cost of a Phase 3 program. The upfront and milestone structure aligns Sentynl's financial commitment with regulatory and commercial progress on alvelestat in AATD-LD.