First-line pembrolizumab plus chemotherapy for advanced HER2-negative gastric or gastroesophageal junction adenocarcinoma: Health-related quality of life from the randomized phase III KEYNOTE-859 trial.

[BACKGROUND] The objective with cancer treatment is prolonging survival; however, treatment should also not negatively impact health-related quality of life (HRQoL). Therefore, the KEYNOTE-859 trial compared the impact of pembrolizumab plus chemotherapy against placebo plus chemotherapy on HRQoL in participants with advanced or metastatic HER2-negative gastric or gastroesophageal (GEJ) adenocarcinoma.

[METHODS] Overall, 1579 participants were randomly assigned 1:1 to pembrolizumab 200 mg or placebo plus chemotherapy every 3 weeks. We report prespecified exploratory patient-reported outcomes (PROs), including change from baseline to week 18, and time to deterioration (TTD) assessed in EORTC QLQ-C30 scales/items, EORTC QLQ-STO22 pain scale, and EQ-5D-5L visual analog scale (VAS).

[RESULTS] Among 1531 participants in the PRO full analysis set (FAS) population for the QLQ-C30 and EQ-5D-5L VAS assessments, least squares mean (LSM) changes from baseline to week 18 were similar between treatments for both assessments. For the 1516 participants in the PRO FAS population for the QLQ-STO22 pain scale, LSM change favored pembrolizumab plus chemotherapy (LSM difference, -2.58; 95 % CI, -4.73 to -0.43). TTD was similar between treatments for the QLQ-C30 scales/items; TTD favored pembrolizumab plus chemotherapy (HR, 0.77; 95 CI, 0.59-1.00) for the QLQ-STO22 pain scale.

[CONCLUSIONS] HRQoL was similar between groups during treatment; the addition of pembrolizumab maintained HRQoL with a numerical trend toward improvement. Combined with safety and efficacy results published at the interim analysis for KEYNOTE-859, HRQoL data support a favorable benefit-to-risk profile for pembrolizumab plus chemotherapy as a first-line treatment option for advanced or metastatic HER2-negative gastric or GEJ adenocarcinoma.