Dr Wise on the Design of a Phase 1b Study of Pasritamig Plus Docetaxel in mCRPC

“Patients were treated with the combination of both agents; they [received] step-up dosing of pasritamig prior to initiation of docetaxel, and then the full dose was given concurrently with docetaxel so that the schedule aligned.”

David R. Wise, MD, PhD, an associate professor in the Department of Medicine and the Department of Urology at NYU Grossman School of Medicine, discussed the design of a phase 1b study (NCT05818683) of pasritamig (JNJ-78278343) plus docetaxel for the treatment of patients with metastatic castration-resistant prostate cancer.

The single-arm study enrolled patients with mCRPC who had previously received at least 1 androgen pathway receptor inhibitor, Wise began. Patients were permitted to have received prior lutetium Lu 177 vipivotide tetraxetan (Pluvicto), he added; prior chemotherapy was also permitted. Other key inclusion criteria included an ECOG performance status or 0 or 1.

Patients received intravenous (IV) pasritamig via step-up dosing at 3.5 mg on day 1 and 18 mg on day 2 before receiving the full 300-mg dose every 6 weeks, Wise explained. Docetaxel at 75 mg/m² was administered every 3 weeks starting on day 15 of the study. This approach was taken so that the agents could be given concurrently via an aligned schedule, he noted.

At baseline, the median age of the study population (n = 51) was 70.0 years (range, 55-84). Most patients had an ECOG performance status of 1 (62.7%) and bone-only disease (51.0%).

The primary end point of the study was the incidence and severity of adverse effects. Secondary end points included overall response rate, prostate-specific antigen response, radiographic progression-free survival, time to response, and duration of response. Initial data from the phase 1b trial were presented during the 2026 Genitourinary Cancers Symposium.

Disclosures: Wise reported holding stock and other ownership interests with Doximity; receiving Honoria from OncLive and ScientiaCME; holding consulting or advisory roles with Bayer, Janssen, K36, OncoC4, and Pfizer; and receiving travel, accommodations, and expenses from Bayer and Pfizer.