Health-related quality of life in patients treated with pembrolizumab for microsatellite instability–high/mismatch repair–deficient advanced solid tumours: Results from the KEYNOTE-158 study

In the KEYNOTE-158 study (NCT02628067), pembrolizumab showed a high objective response rate and durable clinical benefit for patients with previously treated, unresectable/metastatic microsatellite instability-high (MSI-H)/mismatch repair‒deficient (dMMR) non-colorectal solid tumours. We present health-related quality of life (HRQoL) results from the MSI-H/dMMR population (cohort K).Eligible patients had previously treated MSI-H/dMMR advanced non-colorectal solid tumours, measurable disease per RECIST v1.1, and ECOG performance status ≤1. Patients received pembrolizumab 200 mg Q3W for 35 cycles (2 years). The EORTC Quality of Life Questionnaire (QLQ-C30) and EQ-5D-3L were administered at baseline, at regular intervals throughout treatment, and 30 days after treatment discontinuation. Prespecified analyses (exploratory endpoints) included the magnitude of change from baseline to post-baseline timepoints in all patients and by the best overall response for QLQ-C30 global health status (GHS)/QoL, QLQ-C30 functional/symptom scales/items, and EQ-5D-3L visual analogue scale (VAS) score.At data cutoff (October 5, 2020), 351 patients were enrolled, of whom 311 and 315 completed baseline QLQ-C30 and EQ-5D-3L questionnaires, respectively. QLQ-C30 GHS/QoL scores improved from baseline to week 9 (mean [95% CI] change, 3.07 [0.19-5.94]), then remained stable or improved by week 111, with greater improvements observed in patients with a best response of complete response (CR) or partial response (PR) (10.85 [6.36-15.35]). Patients with CR/PR showed improvements in physical (5.58 [1.91-9.25]), role (9.88 [3.80-15.97]), emotional (5.62 [1.56-9.68]), and social (8.33 [2.70-13.97]) functioning, and stable cognitive functioning (1.74 [-1.45 to 4.94]).Pembrolizumab generally improved or preserved HRQoL in patients with previously treated MSI-H/dMMR advanced non-colorectal solid tumours.