David Wise, MD, outlines early data on pasritamig in mCRPC

At the 2026 ASCO Genitourinary (GU) Cancers Symposium in San Francisco, California, David R. Wise, MD, PhD, sat down with Urology Times® to discuss the initial findings from a phase 1b study of pasritamig plus docetaxel in patients with metastatic castration-resistant prostate cancer (mCRPC).¹ Wise is a genitourinary medical oncologist at NYU Langone Health and an associate professor of medicine and urology at the NYU Grossman School of Medicine in New York, New York.

Pasritamig is an investigational bispecific T-cell engager designed to bind both KLK2, a prostate-specific cell surface protein, and CD3 receptor complex on T cells. By simultaneously engaging these 2 targets, the agent redirects and activates T cells directly against prostate cancer cells, Wise explained. He also emphasized that KLK2 is almost exclusively expressed on normal and malignant prostate tissue, with minimal expression elsewhere in the body, making it a particularly “clean” and potentially selective therapeutic target in prostate adenocarcinoma.

The phase 1b trial of the agent was uniquely designed to evaluate pasritamig in combination with established standard-of-care therapies. The abstract presented at ASCO GU focused on the combination with docetaxel in mCRPC. The overarching goal of this cohort was to characterize how pasritamig behaves alongside cytotoxic chemotherapy, rather than in isolation.

In total, the study included 51 patients with mCRPC whose disease progressed following treatment with an androgen-receptor pathway inhibitor. Patients had received a median of 3 prior lines of therapy (range, 1 to 9).

Overall, the combination demonstrated a safety profile consistent with single-agent docetaxel. The most common (20% or higher) treatment-related adverse events (TRAEs) include fatigue (60.8%), alopecia (41.2%), diarrhea and nausea (31.4%, each), peripheral edema (27.5%), peripheral sensory neuropathy (25.5%), and dysgeusia (23.5%). Notably, high-grade cytokine release syndrome was not observed. Grade 3 or higher TRAEs attributed to docetaxel were reported in 29.4% of patients.

Regarding efficacy, the confirmed PSA50 was 64.7%, including 75% in the taxane-naïve patients. The confirmed PSA90 was 39.2%, including 53.6% of taxane-naïve patients.

REFERENCE
1. Patel M. Safety and efficacy of pasritamig (PAS) + docetaxel (DOCE) in participants with metastatic castration-resistant prostate cancer (mcrPc): Initial results of a phase 1b study. Presented at: 2026 American Society of Clinical Oncology Genitourinary Cancers Symposium. February 26-28, 2026. San Francisco, California. Abstract 171. https://www.asco.org/abstracts-presentations/256425