Xencor XmAb819 Posts 45.5% Response Rate in Kidney Cancer Trial, FDA Accelerated Approval Talks Planned for 2027

Xencor's XmAb819, a potential first-in-class ENPP3 x CD3 bispecific T-cell engager, delivered a 45.5% confirmed objective response rate at its proposed 400 mcg/kg intravenous dose in a phase 1 dose-expansion study for advanced clear cell renal cell carcinoma, data presented at ESMO showed. The same cohort recorded a 55% unconfirmed ORR and an 82% six-month progression-free survival estimate by Kaplan-Meier, supporting the selection of 400 mcg/kg as the recommended phase 3 dose.

Xencor plans to discuss a potential FDA Accelerated Approval pathway focused on key ccRCC patient subgroups in the first half of 2027, with a global registration-enabling phase 3 monotherapy study targeted to begin in late 2027. The company is also expanding XmAb819 into other ENPP3-expressing solid tumors, including colorectal cancer, non-small cell lung cancer and papillary renal cell carcinoma.

Analysts have assigned XmAb819 a Strong Buy rating on the back of the ESMO data. Beyond oncology, Xencor is advancing XmAb942 in a phase 2b trial for ulcerative colitis, with interim data expected before the end of 2026.