TJ101 Enters Testing for Advanced Prostate Cancer Patients
The Phase 1 clinical trial launched in September evaluates TJ101, a bispecific antibody-drug conjugate that simultaneously targets two proteins commonly found on cancer cells. This newer generation of cancer treatments combines the targeting precision of antibodies with the cell-killing power of chemotherapy drugs, delivering toxic payloads specifically to cancer cells while sparing normal tissue.
TJ101 targets EGFR, a protein that drives tumor growth, and B7-H3, an immune checkpoint protein that helps cancer cells evade the body’s natural defenses. Both proteins are frequently expressed together in solid tumors, including prostate cancer. Research has shown that B7-H3 is particularly abundant in advanced prostate cancers that have become resistant to hormone therapy.
When the drug binds to cancer cells expressing these proteins, it is internalized and releases a topoisomerase inhibitor that damages DNA and kills the cell. The drug carries eight copies of the toxic payload and can kill neighboring cancer cells that may not express the target proteins through a bystander effect.
The clinical trial will enroll patients with various types of advanced solid tumors who have exhausted standard treatment options, including prostate cancer patients.
The dual-targeting approach reflects growing interest in strategies to overcome cancer’s ability to develop resistance to single-agent therapies. Even if tumor cells develop resistance to targeting one protein, the presence of the second target may still allow the drug to maintain effectiveness.
B7-H3 has attracted significant attention from cancer researchers because it is highly expressed in many tumor types but has limited presence in normal tissues. Studies have shown that B7-H3 levels correlate with prostate cancer progression and poor patient outcomes, while EGFR has been successfully targeted in other cancers but has proven more challenging in prostate cancer.
The trial is being conducted in both China and the United States, reflecting intention to develop the drug for global markets.