Artiva Biotherapeutics halts AlloNK development, cuts staff by 94%
The company stopped work on its lead NK cell therapy after two patient deaths and weak durability data, and is now reviewing strategic options including a possible sale or dissolution.
Artiva Biotherapeutics said on October 27, 2026 that it will stop developing AlloNK® (AB-101), its non-genetically modified, allogeneic NK cell therapy candidate being evaluated in combination with rituximab in rheumatoid arthritis and other B-cell-driven autoimmune diseases, including the planned phase 3 pivotal trial.1 The company said the decision follows a review of overall risk-benefit based on updated clinical data, including longer-term follow-up, and recent Grade 5 safety events.1
One patient in the Phase 2a basket trial died from a fatal neurological event, leukoencephalopathy, that an investigator and an independent safety review assessed as likely related to fludarabine-associated neurotoxicity following lymphodepletion with cyclophosphamide and fludarabine.1 After this report, the FDA asked Artiva to pause enrollment and dosing in the Phase 2a study, and the company also paused the planned Phase 3 trial.1 A second patient died suddenly about two months after starting study treatment, in an event the investigator judged unrelated to AlloNK or any other study treatment component, with cause of death undetermined.1
On the efficacy side, updated data continued to show deep B cell depletion and clinical activity consistent with earlier findings, but longer-term follow-up did not show the durability of response the company said it needed to continue development.1 As a result, no further patients will be dosed in any ongoing AlloNK study, and the planned Phase 3 trial will not begin.1 Artiva also said it will no longer present AlloNK data at ACR Convergence 2026 and will cancel an investor webcast that had been scheduled for November 9, 2026.1
The board is evaluating strategic alternatives to maximize stockholder value, with Leerink Partners engaged as financial advisor.1 The company is also cutting its workforce by about 94% to preserve capital while this review proceeds,1 with the reduction expected to be completed in the first quarter of 2027, per the filing. As of September 30, 2026, Artiva reported roughly $319.1 million in cash, cash equivalents and investments, on a preliminary and unaudited basis.1
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