Los Angeles-based Kairos Pharma Ltd. (NYSE American: KAPA) reported statistically significant interim Phase II data for carotuximab (ENV-105) in metastatic castration-resistant prostate cancer (mCRPC), with median progression-free survival (PFS) of 17.7 months for carotuximab plus apalutamide versus 2 months for apalutamide alone (P=0.0008).
Carotuximab is an antibody targeting CD105, or endoglin, a protein Kairos describes as a driver of treatment resistance and disease relapse. The company said inhibition of CD105/BMP signaling is intended to reverse resistance and restore sensitivity to standard therapies.
Based on the interim efficacy signal, Kairos amended the Phase II protocol to move treatment earlier in the course of androgen-receptor pathway inhibitor resistance. Patients with a PSA increase after initial androgen-signaling inhibitor therapy will be randomized to enzalutamide alone or enzalutamide plus carotuximab. Kairos said it is targeting completion of the Phase II study by Q4 2027.
The company has also expanded development of carotuximab through a July 2026 collaboration with Bayer to evaluate the antibody in combination with Xofigo (radium-223 dichloride) in patients with mCRPC involving bone metastases.