GSK registers Phase 3 trials for mRNA flu vaccine and prostate cancer ADC Ris-Rez

Two new GlaxoSmithKline Phase 3 trial registrations appeared this week, spanning infectious disease and oncology.

• GSK's investigational mRNA seasonal flu vaccine is being tested head to head against a licensed flu shot in adults 65 and older, with the study designed to assess laboratory-confirmed protocol-defined influenza-like illness from Day 15 through the end of the influenza season.¹ The trial is recruiting, with enrollment estimated at 54,000 participants¹ and primary completion expected June 9, 2028.
• Risvutatug rezetecan (Ris-Rez, GSK5764227), a B7-H3 antibody drug conjugate, has entered Phase 3 testing in metastatic castration-resistant prostate cancer under the study titled "EMBOLD Prostate-302." Participants in the comparator arm will receive physician's choice of best supportive/standard of care, with or without androgen receptor pathway inhibitors enzalutamide or abiraterone (with prednisone or prednisolone).² The primary endpoints are radiographic progression-free survival and overall survival, measured over approximately 169 weeks.² The study is not yet recruiting, with enrollment estimated at 684 participants² and primary completion expected December 19, 2029.