Artiva Cuts 94% of Staff as Trial Deaths, Weak Data End AlloNK

Artiva Biotherapeutics, a San Diego biotech, will stop developing its lead cell therapy, AlloNK, and cut about 94% of its staff. The company said on October 27, 2026 that two trial participants had died and that patient responses did not last long enough. Its board is now weighing a merger, a sale or licensing of assets, or winding the company down.

What happened

AlloNK is a cryopreserved natural killer cell therapy made from donor cells. Artiva was testing it with rituximab in rheumatoid arthritis and other autoimmune diseases driven by B cells.

• First death: a participant in a Phase 2a basket trial died of leukoencephalopathy, a disorder of the brain. The investigator and an independent safety review judged it likely linked to fludarabine, a chemotherapy drug given before the cells. The FDA then asked Artiva to pause enrollment and dosing in that study.
• Second death: another participant died suddenly about two months after starting treatment. The investigator judged it unrelated to AlloNK or the rest of the regimen. The cause has not been found.
• Durability: longer follow-up showed that responses did not last long enough to meet the company's bar for further development, Artiva said.

The planned Phase 3 pivotal trial will not start. Artiva also dropped a data presentation at ACR Convergence 2026 and cancelled a November 9 investor webcast. Leerink Partners is advising on the strategic review.

Why it matters

Artiva reported about $319.1 million in cash, cash equivalents and investments at September 30, based on preliminary, unaudited figures. BioSpace reported that this was down from $349.1 million on June 30. The company was founded in 2019 and raised $179 million in its 2024 IPO, according to BioSpace.

The news adds to safety questions around cell therapies for autoimmune disease. BioPharma Dive noted that Novartis and Bristol Myers Squibb paused several trials of their patient-derived cell therapies in August over safety concerns. Artiva's product came from donors, not from patients. Chief executive Fred Aslan said the company plans to publish the fludarabine case, given how widely the drug is used to prepare patients for cell therapy.

What it means for people in the industry

Artiva had 115 employees as of June 30, according to an SEC filing cited by BioSpace. BioSpace estimated that the cut could affect about 108 people. Artiva told regulators it expects to finish the reduction in the first quarter of 2027. It said it cannot yet estimate the total cost of the wind down.

The company will close out its clinical program and keep up safety monitoring. It said it will not give more updates unless the board approves a specific plan, the process ends, or the law requires it. The next step to watch is the board's choice among a merger, an asset deal or liquidation.

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Sources

• Artiva Biotherapeutics Announces Strategic Update and Discontinues Development of AlloNK®, GlobeNewswire (Artiva Biotherapeutics)
• Artiva Biotherapeutics, Inc. Form 8-K, U.S. Securities and Exchange Commission
• After 2 patient deaths and cell therapy durability concerns, Artiva cuts 94% of workforce, BioSpace
• Artiva to quit autoimmune cell therapy work, cut staff after patient deaths, BioPharma Dive