Xaluritamig, a novel immunotherapy, is going to be tested in combination with standard hormone therapies for metastatic hormone-sensitive prostate cancer (mHSPC).
Building on promising early results from its use in metastatic castration-resistant prostate cancer (mCRPC), where tumors no longer respond to hormone therapy, Xaluritamig could redefine treatment for men facing aggressive prostate cancer.

Xaluritamig is a bispecific T-cell engager, designed to bridge the body’s immune system with cancer cells. It targets STEAP1, a protein abundant on prostate cancer cells, and CD3 on T cells, the body’s cancer-killing immune cells, triggering a targeted attack on tumors. Unlike chemotherapy, which can damage healthy cells, Xaluritamig zeros in on cancer cells with high STEAP1 expression, sparing most normal tissues.

Preclinical studies in mice showed it halted tumor growth with minimal side effects, paving the way for human trials. The current trial is enrolling about 60 men with mHSPC across global sites to evaluate Xaluritamig’s safety, tolerability, and effectiveness when combined with the androgen receptor pathway inhibitors (ARPIs) abiraterone and darolutamide.

These drugs, cornerstones of mHSPC treatment, block hormones that fuel cancer growth. The study will track tumor shrinkage (objective response rate), time to disease progression, overall survival, and reductions in PSA levels, a key prostate cancer marker, while monitoring side effects like cytokine release syndrome, a flu-like reaction common with T-cell therapies.

In early result on mCRPC presented at ESMO 2024, Xaluritamig monotherapy showed a 41% response rate in heavily pretreated mCRPC patients at higher doses, with tumors shrinking for a median of 9.2 months. These encouraging results, despite manageable side effects, suggest Xaluritamig could be a powerful tool earlier in the disease, like in mHSPC, where it might delay progression to mCRPC.

Clinical trial.