Acelyrin and Alumis plan to close their merger in the second quarter of 2025, pending clearances and shareholder approval.
Acelyrin declined a surprise acquisition offer from Concentra Biosciences on Tuesday, instead doubling down on its previously announced merger with fellow immune specialist Alumis.
“The unsolicited indication of interest from Concentra Biosciences, LLC . . . is not reasonably expected to result in a superior proposal to the planned merger with Alumis Inc.,” Acelyrin wrote in its press announcement—a conclusion that it reached after consulting with independent financial and legal advisors.
“The Acelyrin Board of Directors is confident that the all-stock transaction with Alumis maximizes long-term value for Acelyrin stockholders,” the news release stated. Acelyrin management recommends that shareholders back the merger.
Acelyrin and Alumis expect to close the transaction in the second quarter of 2025, pending regulatory clearances, approval by stockholders and other customary conditions. Once complete, the combined entity will carry Alumis’ name and will pool together the two companies’ standing resources: around $448 million from Acelyrin and $289 million from Alumis. The resulting cash position should be enough to tide the new company over until 2027.
The post-merger Alumis will also advance a drug pipeline with the combined assets of both companies. This includes the tyrosine kinase 2 inhibitors ESK-001, being tested in mid- to late-stage trials for moderate-to-severe plaque psoriasis and lupus, and A-005, in early-stage development for neuroinflammatory and neurodegenerative disorders.
The combined company will also work on Acelyrin’s lonigutamab, a subcutaneous monoclonal antibody in Phase II for thyroid eye disease and Acelyrin’s only remaining candidate after the company announced in December 2024 that it had discontinued the development of its lead candidate izokibep, an investigational IL-17A inhibitor that had been in trials for psoriasis and other inflammatory conditions. Findings for lonigutamab revealed in January 2025 showed that the asset could elicit “clinically meaningful and competitive improvements” in various disease symptoms, including clinical activity and diplopia, the biotech said at the time.
Acelyrin and Alumis revealed plans to merge in early February, but two weeks later Concentra sought to disrupt the transaction by offering to snap up Acelyrin for $3 per outstanding share. The Kevin Tang-controlled company also added a contingent value right offer that would entitle Acelyrin to 80% of proceeds from deals concerning its assets and intellectual properties.
Concentra has previously tried to get in between prospective partners. In March 2023, for instance, Concentra broke up a planned merger between Jounce Therapeutics and Redx Pharma, ultimately, winning Jounce over.
