Zev A. Wainberg, MD discusses the efficacy findings of pembrolizumab monotherapy versus chemotherapy for patients with PD-L1–positive advanced gastric and gastroesophageal junction cancer of high combined positive score in cohort 1 of the phase II KEYNOTE-059 and in the phase III KEYNOTE-061 and KEYNOTE-062 studies.
Zev Wainberg, MD, an assistant professor of medicine, and co-director of the University of California, Los Angeles (UCLA) GI Oncology Program, UCLA, discusses the efficacy findings of pembrolizumab (Keytruda) monotherapy versus chemotherapy for patients with PD-L1—positive advanced gastric/gastroesophageal junction cancer who have a high combined positive score (CPS) in cohort 1 of the phase II KEYNOTE-059 and in the phase III KEYNOTE-061 and KEYNOTE-062 studies.
In KEYNOTE-059, there were around 54 patients who had a CPS score ≥10, and close to 18% of those patients achieved very durable responses. These results provide more confirmation that the optimal use for pembrolizumab in gastric cancer is for the treatment of patients with high CPS scores, says Wainberg.
The randomized studies showed that patients with high CPS scores had better efficacy with pembrolizumab compared with those who had low CPS scores. This was especially true in the subgroup of patients with microsatellite instability—high (MSI-H) disease. MSI-H patients had the most significant benefit from pembrolizumab in both the first- and second-line studies.