Artiva halts AlloNK development and cuts workforce by 94% after reviewing treatment data
Key Facts
Artiva Biotherapeutics announced on October 27, 2026, that it would halt development of its cell therapy AlloNK, also known as AB-101, and cut its workforce by about 94%, following a review of long-term efficacy data and safety risks. The company said longer follow-up did not show the durability of clinical responses it considers necessary to continue development, despite sustained deep B-cell depletion and clinical activity consistent with earlier results. The therapy was being studied with rituximab for rheumatoid arthritis and other B-cell-driven autoimmune diseases. Artiva said its decision followed a comprehensive risk-benefit assessment and was not based on the deaths alone. The move ends a clinical program that had been targeting a pivotal Phase 3 trial.
The safety review included the death of a participant in a Phase 2a trial following encephalopathy after treatment. The investigator and an independent safety review assessed the case as likely related to neurotoxicity caused by fludarabine, used in the conditioning regimen. After being notified of the case, the U.S. Food and Drug Administration asked Artiva to suspend patient enrollment and dosing in the study. The company also halted dosing and enrollment in the Phase 3 trial it had planned. In a second case, a participant died suddenly about two months after starting treatment; the investigator considered the death unrelated to AlloNK or any other component of the study regimen, while its cause remained undetermined.
The decision followed preliminary data in May showing a response in 5 of 7 patients with treatment-resistant rheumatoid arthritis, or 71%, based on six months of follow-up through April 3, 2026. The company had planned a registration-enabling trial with about 150 patients, comparing AlloNK plus rituximab with rituximab alone and measuring ACR50 response after six months. In September, Artiva said it expected updated data from at least 20 patients, each with six months or more of follow-up, but later canceled its presentation at ACR Convergence 2026. Artiva Chief Executive Fred Aslan said in September that patients with treatment-resistant rheumatoid arthritis still faced an unmet medical need despite receiving multiple advanced therapies. However, the longer follow-up did not meet the durability threshold the company said it needed to justify continuing development.
Alongside halting the program, Artiva said it was cutting its workforce by about 94% to preserve capital and had appointed Leerink Partners as financial adviser. The company’s announcement does not specify the final number of employees who will leave; its annual report said it had 104 full-time employees as of December 31, 2025. The board is considering alternatives including a merger, business transaction, asset sale or licensing, or dissolving and liquidating the company, with no assurance that any deal or specific outcome will result. The fate of the company’s assets and its strategic options now move to the fore as it evaluates alternatives. Artiva shares closed at $6.16 on October 26 and $4.27 on October 27; Reuters reported that they fell 30% in premarket trading on the day of the announcement.
The company estimated that cash, cash equivalents and investments totaled about $319.1 million as of September 30, 2026, based on a preliminary, unaudited estimate. It had $349.4 million at the end of June and said then that its cash runway was expected to fund operations through 2029; in September, it reiterated that its cash runway extended into that year and beyond the planned timing of the trial’s initial readout. In the second quarter of 2026, it reported a net loss of $25 million, compared with $21.3 million in the same quarter of 2025. Following the decision to halt development, no new participants will receive doses in any ongoing AlloNK study, and the pivotal Phase 3 trial will not begin. Artiva said it would coordinate with the FDA, investigators and institutional review boards to close the program, while continuing safety monitoring and reporting as required. It also canceled an investor webcast scheduled for November 9, 2026.