Phase 1/2 PM54 + pembrolizumab tests tubulin (microtubule) inhibition paired with PD-1 blockade.

This multicenter, open-label Phase 1/2 trial from PharmaMar evaluates PM54 (a small-molecule microtubule/tubulin inhibitor) combined with pembrolizumab (Keytruda; Merck/MSD’s PD-1–blocking monoclonal antibody) in adults with previously treated, advanced/metastatic, progressive, unresectable solid tumors. Part 1 is a safety run-in with PM54 dose escalation alongside pembrolizumab to establish a recommended combination dose; Part 2 expands at that dose to estimate antitumor activity using investigator-assessed endpoints such as objective response rate and clinical benefit rate. The scientific/commercial angle is a cytotoxic “backbone” designed to trigger tumor cell death and potentially increase immunogenicity, layered onto a widely used checkpoint inhibitor platform. Today, patients with refractory metastatic solid tumors typically cycle through tumor-specific options (targeted therapy when actionable alterations exist, immunotherapy in responsive histologies/biomarker-defined subsets, and multiple sequential chemotherapies/ADCs), so this study explores whether a new tubulin agent can deepen or restore responses when prior systemic therapy has failed.