For patients with PD-L1-positive, HER2-negative advanced cancer of the stomach or gastroesophageal junction, pembrolizumabom therapy (as first-line treatment) is not inferior to the standard chemotherapy for efficiency, but has a lower toxicity.
Furthermore, pembrolizumab provides better overall survival of patients with high expression of PD-L1.
"Our study demonstrates that pembrolizumab as a first-line treatment can provide new opportunities for people with newly diagnosed advanced cancer of the stomach or gastroesophageal transition" - researchers reported at the annual meeting of the American Society of Clinical Oncology in Chicago press briefing.
Pembrolizumab (Keytruda, Merck) was approved in the US in 2017 for the treatment of recurrent, locally advanced or metastatic cancer of the stomach or gastroesophageal junction, which express PD-L1 with a combined positive assessment (CPS) one or more.
In the third phase of the study KEYNOTE-062 was attended by 763 patients, whose average age was 62 year. 69% of them suffered from stomach cancer, and 30% - from the gastroesophageal transition of cancer. All tumors were ER2-negative. About a quarter of the patients had previous resection of the tumor. CPS in all patients had at least one, and in 281 participants - ten or more.
Patients were randomized into three groups. Members of the first group received intravenously pembrolizumab, from the second - pembrolizumab and standard chemotherapy, and from the third - standard chemotherapy and placebo. Median follow-up was 11.3 months.
Patients with CPS equal to one or greater, overall survival (OS) using pembrolizumaba not inferior survival with chemotherapy. Median OS was 10.6 months and 11.1 months pembrolizumabom with chemotherapy.
Participants whose CPS was 10 or more, the overall survival was higher when using pembrolizumaba, compared with chemotherapy. Median OS was 17.4 months with pembrolizumabom against 10.8 months with chemotherapy. Two years later, 39% of patients who received pembrolizumab and 22% who received chemotherapy were alive.
The combination of chemotherapy and pembrolizumab not exceed chemotherapy with respect to the OS and PFS, regardless of the figure CPS.
Patients treated pembrolizumab had fewer side effects and fewer participants discontinued therapy due to adverse events.
Severe toxic effects of third degree or higher were recorded in 17% of participants who took pembrolizumab, in 73% of patients receiving pembrolizumab and chemotherapy, and 69% of patients treated with chemotherapy alone. The most common side effects were nausea and fatigue.