Dr. Mehta on Immunotherapy in Gastric/GEJ Cancer

Rutika Mehta, MD, MPH, gastrointestinal medical oncologist at Moffitt Cancer Center, discusses the use of immunotherapy in patients with gastric or gastroesophageal junction (GEJ) adenocarcinoma.

In the KEYNOTE-059 trial, patients who had progressed on 2 prior lines of therapy received pembrolizumab (Keytruda) monotherapy in the third-line setting. The agent resulted in an improvement in overall survival (OS), as well as an overall response rate of 13.3% in patients with PD-L1 positivity, says Mehta. These results served as the basis for the September 2017 FDA approval for use in this patient subset. Subsequently, results from the phase III KEYNOTE-061 study were announced. For this trial, investigators randomized patients to receive either pembrolizumab or paclitaxel. However, the trial failed to result in an improvement in OS or progression-free survival.

However, a subgroup analysis revealed that some subgroups showed benefit with the PD-1 inhibitor. This benefit was specific to patients with microsatellite instability-high tumors, as well as those with a CPS of ≥10 in the PD-L1—positive population, says Mehta. Although it is not recommended to use pembrolizumab in the second-line, a small subset of patients may derive benefit from the drug in that setting.