Patient-reported outcomes in the GARNET trial in patients with advanced or recurrent mismatch repair-deficient/microsatellite instability-high endometrial cancer treated with dostarlimab

OBJECTIVE: There is an increase in patient-reported outcome assessments to gain information on new drug candidates from the patient’s perspective. A data gap remains in patient-reported outcome measurements for anti-programmed death 1 (anti-PD-1) therapies in endometrial cancer. We present patient-reported outcome measures collected from patients with mismatch repair-deficient/microsatellite instability-high advanced or recurrent endometrial cancer treated with dostarlimab, an anti-PD-1 monoclonal antibody, in an expansion cohort of the GARNET trial. METHODS: GARNET (NCT02715284) is a phase I single-arm study of dostarlimab monotherapy in multiple tumor types. Patients with advanced or recurrent mismatch repair-deficient/microsatellite instability-high endometrial cancer were treated with 500 mg of intravenous dostarlimab once every 3 weeks for four cycles, then 1000 mg of intravenous dostarlimab every 6 weeks. Patient-reported outcome assessments were an exploratory endpoint, measured using the European Organization for Research and Treatment of Cancer Quality of Life Questionnaire C30 (EORTC QLQ-C30). RESULTS: At data cut-off, 88 patients with mismatch repair-deficient endometrial cancer were included in the analysis. Patient-reported outcome assessment completion was >95.5% throughout cycle 7 of the trial, with no individual domain completion <90.9%. Quality of life, emotional functioning, and social functioning showed improvement compared with baseline. All symptom scores showed either improvement or stability from baseline through cycle 7. Categorical change in response across all symptom scales and single-item response scores showed stability or improvement for most patients. For patients who saw a worsening of their categorical change in response, ≤7.4% experienced a 2-category worsening and ≤2.5% experienced a 3-category worsening. CONCLUSIONS: Most patients remained stable or had improved quality of life while receiving dostarlimab for the treatment of recurrent or advanced mismatch repair-deficient endometrial cancer. TRIAL REGISTRATION NUMBER: NCT02715284.