A Phase 3 trial is recruiting 675 patients to be randomized to Xaluritamig versus cabazitaxel or an AR switch, aiming to establish its superiority as a second-line treatment.
Xaluritamig is a STEAP1-targeted T-cell engager being developed for metastatic castration-resistant prostate cancer (mCRPC). It binds to STEAP1 on cancer cells and CD3 on T-cells, facilitating the targeted killing of prostate cancer cells. STEAP1 is highly expressed in prostate cancer and minimally expressed in normal tissues, which enhances precision.
The most common side effects are Cytokine Release Syndrome (CRS), which occurred in 75% of patients, and musculoskeletal inflammatory events seen in 76% of patients. These side effects are generally manageable with steroids or tocilizumab, or by holding doses and administering steroids or tocilizumab. First-dose administration requires 24-hour hospital monitoring.
From the previous phase 1/2 trials:
- Efficacy results include 36-60% of patients achieving a ≥50% PSA reduction (PSA 50), and 20-30% achieving ≥90% reductions (PSA 90).
- Objective responses ranged from 14-28%, with 20% of patients with liver metastases showing a response.
- The median radiographic progression-free survival (rPFS) was 7.7 months, extending to 8.3 months at doses of 0.75 mg or higher, and median overall survival (OS) reached 17.7 months.
Remember that we are talking about a heavily pretreated population.
After Radiation Therapy 