The following article features coverage from the American Society of Clinical Oncology 2019 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Initial therapy with pembrolizumab may result in comparable overall survival as standard chemotherapy in patients with PD-L1–positive, HER2-negative, advanced gastric or gastroesophageal junction cancer, according to research presented at the 2019 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.1

For the study, researchers recruited 763 patients; median patient age was 62 years. Of all the patients, 69% had gastric cancer and 30% had gastroesophageal junction adenocarcinoma. Moreover, 26% of all the patients had previous gastric surgery to remove a tumor.

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The investigators assessed PD-L1 expression in the patients using a combined positive score (CPS) of 1 or more. The researchers randomized the patients in a 1:1:1 ratio to receive intravenous pembrolizumab 200 mg every 3 weeks for up to 35 cycles; pembrolizumab 200 mg every 3 weeks for up to 35 cycles plus chemotherapy; or chemotherapy plus placebo. The researchers followed the participants for a median of 11.3 months.

The results showed that among patients with PD-L1 CPS of 1 or more, median overall survival was 10.6 months for those who received pembrolizumab compared with 11.1 months for those who received chemotherapy. Moreover, among patients with PD-L1 CPS 10 or more, overall survival was 17.4 months for those who received pembrolizumab compared with 10.8 months for those who received chemotherapy.

Among patients with PD-L1 CPS of 1 or more, progression-free survival was 2.0 months for those who received pembrolizumab compared with 6.4 months for those who received chemotherapy. Among patients with CPS 10 or more, progression-free survival was 2.9 months for those who received pembrolizumab compared with 6.1 months for those who received chemotherapy.

The researchers also found that both overall survival and progression-free survival were similar between patients who received the combination of pembrolizumab and chemotherapy and those who received chemotherapy alone, irrespective of CPS score.

Pembrolizumab had a more favorable safety profile than the other 2 treatments. Grade 3 to 5 drug-related adverse events were found in 17% of patients who received pembrolizumab, 73% of those who received the combination of pembrolizumab and chemotherapy, and 69% of those who received chemotherapy.

“To conclude, a similar benefit on overall survival of pembrolizumab versus chemotherapy was observed as first-line treatment in patients with advanced gastric or gastroesophageal junction cancer with a CPS score of [equal to or] more than 1,” said lead study author Josep Tabernero, MD, PhD, head of the medical oncology department at the Vall d’Hebron University Hospital in Barcelona and the director of the Vall d’Hebron Institute of Oncology in Barcelona, Spain. “There was also a favorable effect on overall survival of pembrolizumab versus chemotherapy in those patients with tumors with PD-L1 positivity CPS equal [to] or more than 10.”

Dr Tabernero added: “Patients receiving pembrolizumab had [a] better tolerability profile than those that received chemotherapy.”

Read more of Cancer Therapy Advisor‘s coverage of ASCO’s annual meeting by visiting the conference page.

References

  1. Tabernero J, Van Cutsem E, Bang, YJ. Pembrolizumab with or without chemotherapy versus chemotherapy for advanced gastric or gastroesophageal junction (G/GEJ) adenocarcinoma: The phase III KEYNOTE-062 study. Presented at: 2019 American Society of Clinical Oncology (ASCO) Annual Meeting; May 31-June 4, 2019; Chicago, IL. Abstract LBA4007.