Artiva halts AlloNK NK cell program after patient death, cuts 94% of staff

Artiva Biotherapeutics discontinued its lead NK cell therapy AlloNK (AB-101) after a patient died of leukoencephalopathy linked to conditioning agent fludarabine and longer-term data showed responses did not hold. The company will cut about 94% of its workforce and seek a buyer with roughly $319.1 million in cash.

• Patient died of leukoencephalopathy likely tied to fludarabine
• Longer-term follow-up showed clinical responses did not hold up
• Workforce cuts will affect about 94% of Artiva staff
• Company held about $319.1 million in cash as of September 30, 2026