Xencor Shares Rise Pre-Bell After Kidney Cancer Trial Shows 45.5% Response Rate

06:47 AM EDT, 10/26/2026 (MT Newswires) -- Xencor (XNCR) stock jumped 25% during Monday premarket trading after the company announced over the weekend that its experimental cancer drug XmAb819 demonstrated a 45.5% confirmed objective response rate in a Phase 1 study of patients with advanced clear cell renal cell carcinoma. In the 400 mcg/kg dose group, five of 11 evaluable patients achieved confirmed partial responses, while one additional patient had an unconfirmed response, it said. The six-month progression-free survival rate was 82%, and median progression-free survival was not reached, it added.