On July 22, 2026 Kairos Pharma, Ltd. (NYSE American: KAPA), a clinical-stage biopharmaceutical company focused on overcoming cancer drug resistance, reported a strategic collaboration with Bayer to evaluate Kairos Pharma’s lead antibody ENV-105 (carotuximab), a first-in-class CD105/BMP signaling inhibitor, in combination with Bayer’s XOFIGO (radium-223 dichloride) in metastatic castration-resistant prostate cancer (mCRPC) involving bone.

Schedule your 30 min Free 1stOncology Demo!
Discover why more than 1,500 members use 1stOncology™ to excel in:

Early/Late Stage Pipeline Development - Target Scouting - Clinical Biomarkers - Indication Selection & Expansion - BD&L Contacts - Conference Reports - Combinatorial Drug Settings - Companion Diagnostics - Drug Repositioning - First-in-class Analysis - Competitive Analysis - Deals & Licensing

                  Schedule Your 30 min Free Demo!

Kairos Pharma’s current programs with ENV-105 include a Phase 1 trial in EGFR-driven non-small cell lung cancer and a Phase 2 trial for castrate resistant prostate cancer. Last year, Kairos announced positive interim efficacy data from the Phase 2 trial showcasing median progression-free survival was more than 13 months, a significant improvement from standard of care. These data were presented at the 2025 ESMO (Free ESMO Whitepaper) Congress in Berlin. XOFIGO is the first and only FDA-approved alpha-emitting radiopharmaceutical for mCRPC with symptomatic bone metastases and is currently advancing through additional combination studies, including the Phase III PEACE-3 trial, which demonstrated a 24% reduction in mortality risk when combined with enzalutamide (HR 0.76; p=0.009).

"Drug resistance remains one of the greatest challenges in advanced prostate cancer, and XOFIGO, like many standard-of-care therapies, can lose efficacy over time," said John Yu, M.D., Chief Executive Officer of Kairos Pharma. "ENV-105 has already demonstrated the ability to re-sensitize tumors to existing treatments with a strong safety profile, and this collaboration with Bayer represents a major milestone in our mission to deliver more durable and more effective treatment regimens for patients with metastatic prostate cancer."

Previous published work has demonstrated the efficacy of ENV-105 in radiation sensitization in prostate cancer preclinical models. CD105 is upregulated in response to standard androgen receptor inhibition and in responses to ionizing radiation, driving pro-survival BMP-SMAD signaling pathways underlying therapy resistance. Targeting CD105 with ENV-105 re-sensitizes resistant tumors and may extend the duration and depth of response to XOFIGO’s targeted alpha therapy.

Neil Bhowmick, Ph.D., Chief Scientific Officer and Principal Investigator stated, "CD105’s role as a central resistance mechanism validated now across multiple drug classes makes this collaboration scientifically compelling and clinically timely, given XOFIGO’s recent Phase III momentum."

(Press release, Kairos Pharma, JUL 22, 2026, View Source [SID1234669367])