SAN FRANCISCO – Maintenance therapy with avelumab does not prolong survival in patients with advanced gastric cancer relative to continued chemotherapy, results of the JAVELIN Gastric 100 trial suggest.
Susan London/MDedge News
Dr. Markus H. Moehler
However, it may not be end of the line for avelumab in this setting, as the checkpoint inhibitor may benefit certain subgroups of patients, according to Markus H. Moehler, MD, PhD, of the Johannes Gutenberg-University Clinic in Mainz, Germany, who presented results from the trial at the symposium.
In the phase 3 trial, investigators enrolled 805 patients with untreated locally advanced or metastatic HER2-negative gastric or gastroesophageal junction cancer. All patients received first-line chemotherapy.
The 499 patients (62%) who did not experience progression were randomized to receive the anti– programmed death-ligand 1 (PD-L1) antibody avelumab (n = 249) or continued chemotherapy (n = 250). There were 6 patients in the avelumab arm and 12 in the chemotherapy arm who did not receive maintenance treatment, and 7 patients in the chemotherapy arm received best supportive care as maintenance.
Efficacy and safety
The minimum follow-up was 18 months. The median overall survival in the entire population was about the same for both treatment groups, 10.4 months with avelumab and 10.9 months with chemotherapy (P = .1779).
Findings were similar among the 12.3% of patients whose tumors were PD-L1 positive as defined by staining of at least 1% of tumor cells. The median overall survival in this group was 16.2 months with avelumab and 17.7 months with chemotherapy (P = .6352).
On exploratory analysis, results with avelumab were more favorable among the 64.3% of patients whose tumors were PD-L1 positive as defined by a combined positive score (CPS) of 1 or greater. The median overall survival in this group was 14.9 months with avelumab and 11.6 months with chemotherapy.
In subgroup analyses by other characteristics, avelumab appeared to have the edge among patients free of metastases at baseline. In this group, the median overall survival was 16.3 months with avelumab, compared with 10.7 months with chemotherapy (hazard ratio for death, 0.52).
Among all patients, the pattern comparing avelumab with chemotherapy was similar for median progression-free survival (3.2 months vs. 4.4 months) and objective response rate (13.3% vs. 14.4%). The median duration of response was not reached.
“JAVELIN Gastric 100 did not meet its primary objective of demonstrating superior overall survival with avelumab maintenance versus chemotherapy or best supportive care in gastric cancer, either in all randomized patients or in the PD-L1–positive population,” Dr. Moehler said. “However, avelumab maintenance showed clear clinical activity. Further studies are needed to identify patients who can derive benefit from checkpoint inhibitor therapy across the continuum of care with gastric and gastroesophageal junction cancer.”
The avelumab and chemotherapy groups had similar rates of any grade 3 or higher adverse events (54.3% vs. 53.8%), but the avelumab group had a lower rate of treatment-related grade 3 or higher adverse events (12.8% vs. 32.8%).