Artiva halts AlloNK development and cuts 94% of workforce after data review
Key Facts
Artiva Biotherapeutics said on October 27 that it was halting further development of AlloNK, including a planned pivotal Phase 3 trial, after longer-term follow-up data showed that clinical response durability had not reached the threshold the company required to continue the program. The company said B-cell depletion and clinical response data remained consistent with results it had previously reported, but its decision followed a review of the overall risk-benefit balance. It also announced a reduction of about 94% in its workforce and the start of an evaluation of strategic alternatives. It has retained Leerink Partners as financial adviser. The decision ends planned development of a treatment the company was testing for B-cell-driven autoimmune diseases.
Artiva reported two Grade 5 safety events: leukoencephalopathy, which it said its assessment suggested was likely associated with fludarabine toxicity, and a second event considered unrelated to any component of the study treatment. These events were part of the company's risk-benefit review, alongside the longer-term follow-up result on response durability. AlloNK was an unmodified, donor-derived natural killer cell therapy candidate administered with rituximab. The program studied the combination for rheumatoid arthritis and other B-cell-driven autoimmune diseases. Halting development would cancel the plan to advance to a registrational Phase 3 trial in treatment-resistant rheumatoid arthritis.
The initial results had appeared encouraging to the company. In its second-quarter results update, it said 5 of 7 patients with treatment-resistant rheumatoid arthritis who completed 6 months of follow-up had achieved an ACR50 response as of the April 3, 2026 data cutoff. Artiva said in the same update that, as of that date, no patient had lost the response, required high-dose steroids or started a new b/tsDMARD treatment. But the longer-term data underlying the company's decision did not meet its response-durability criterion for continued development. The initial response signal therefore differed from the company's later assessment of its durability, the criterion it tied to continuation of the program. The company had planned a randomized trial comparing AlloNK plus rituximab with rituximab alone in about 150 patients, measuring ACR50 response after 6 months.
In September, Artiva expected the planned trial to test whether the combination could achieve an ACR50 response above 50%, compared with an expected rate of about 20% with rituximab alone, and to report topline results by the end of 2028. It was also expecting updated data in the second half of 2026 from at least 20 patients, each with at least 6 months of follow-up, including at least 10 patients meeting the pivotal trial's key eligibility criteria. Chief Executive Fred Aslan said at the time that the company was targeting a start for the FDA-aligned Phase 3 trial in the second half of 2026. He added that projected cash runway through 2029 extended beyond the then-planned topline readout. The halt marks a shift from the clinical timeline the company presented weeks before its decision.
Artiva said in August that it had $349.4 million in cash, cash equivalents and investments on June 30, 2026, and said that balance was expected to fund operations through 2029. The company recorded a net loss of $25.0 million in the quarter ended June 30, compared with a loss of $21.3 million in the same quarter of 2025. On October 27, it reported that cash, cash equivalents and investments totaled about $319.1 million on September 30, in a preliminary and unaudited estimate. This means the decision to halt the program came with a substantial cash and investment balance, according to the figures the company reported, alongside a broad workforce reduction and an evaluation of alternatives. The workforce reduction announcement alone does not specify how these resources will be used or which alternatives the company will choose.
In trading, Artiva shares closed at $6.16 on October 26, according to EL7 data. They had closed at $6.56 on October 20, $6.49 on October 21, $6.20 on October 22 and $6.15 on October 23. These prices do not establish when the company's decision was issued relative to the October 26 session. Artiva is scheduled to present AlloNK data at the ACR Convergence conference from November 6 to 11, 2026. It also announced a webcast to review the data on November 9 at 8:15 a.m. Eastern Time, its next announced date to discuss the data.