Alumis and Acelyrin Announce Merger, Bolstering Immune-Mediated Disease Pipeline

In a significant move that reshapes the landscape of immune-mediated disease research, California-based biotechnology companies Alumis and Acelyrin have announced their intention to merge. The all-stock deal, expected to close in the second quarter of 2025, will see Alumis absorb Acelyrin, creating a combined entity with a robust pipeline and substantial financial resources.

Merger Details and Financial Implications

The merger agreement stipulates that Acelyrin stockholders will receive 0.4274 shares of Alumis stock for each share they own, resulting in Acelyrin shareholders owning approximately 45% of the combined company, with Alumis shareholders retaining the remaining 55%. The new entity will retain the Alumis name and will be led by the current Alumis executive team, including CEO Martin Babler.

The financial landscape of the merged company looks promising, with a combined cash position of $737 million. This includes $448 million from Acelyrin and $289 million from Alumis, providing a runway that extends into 2027. This substantial financial cushion is expected to support multiple planned key data readouts and advance the company's late-stage clinical pipeline.

Pipeline and Development Strategy

The merger brings together a diverse portfolio of drug candidates targeting immune-mediated conditions:

1. ESK-001: Alumis' oral tyrosine kinase 2 (TYK2) inhibitor, currently in Phase III trials for moderate-to-severe plaque psoriasis. Late-stage data for this indication are expected in the first half of 2026. The drug is also being investigated for systemic lupus erythematosus.

2. A-005: Another TYK2 inhibitor from Alumis' pipeline, targeting neuroinflammatory and neurodegenerative conditions such as multiple sclerosis and Parkinson's disease. A Phase II trial is expected to commence in the second half of 2025.

3. Lonigutamab: A subcutaneous anti-IGF-1R antibody from Acelyrin's portfolio, currently in Phase II studies for thyroid eye disease. The merged company plans to re-evaluate the development program for lonigutamab to confirm its differentiation in a capital-efficient manner.

Notably absent from the combined pipeline is Acelyrin's former lead asset, izokibep, which was discontinued following failed Phase IIb/III trials in uveitis and hidradenitis suppurativa.

Industry Impact and Market Reaction

The merger comes at a time when both companies have faced challenges in the stock market. Acelyrin and Alumis, both recent Nasdaq entrants, have seen significant declines in their share prices since their initial public offerings. Acelyrin's IPO in April 2023 raised $540 million, while Alumis' June 2024 offering netted $250 million.

The combined entity aims to leverage its expanded portfolio and financial strength to compete in the increasingly crowded field of oral autoimmune therapies. With Bristol Myers Squibb's Sotyktu as the only approved TYK2 inhibitor on the market, Alumis is positioning its candidates, particularly ESK-001, as potentially best-in-class molecules.

Martin Babler, CEO of Alumis, emphasized the strategic benefits of the merger, stating, "This merger will give us financial flexibility and runway to work on our late-stage clinical pipeline of immune therapies. As we move forward together, we will maintain financial discipline and a flexible capital allocation strategy."