Aims: GARNET (NCT02715284) is a phase 1 study assessing antitumor activity and safety of dostarlimab, an anti-programmed death (PD)-1 receptor therapy, in patients with solid tumors. This analysis evaluated the time of onset of treatment-related AEs(TRAEs) and immune-related (ir) TRAEs over the course of dostarlimab treatment in patients with dMMR and MMRp EC in GARNET.
Methods: Patients with advanced/recurrent dMMR or MMRp EC that progressed on/after a platinum regimen received 500 mg dostarlimab every 3 weeks (Q3W) for 4 cycles, then 1000 mg Q6W until disease progression or discontinuation.
Results: In total, 126 patients with dMMR EC and 145 patients with MMRp EC were included in the safety population. Few TRAEs were seen in ≥10% of patients: fatigue (17.3%), diarrhea (14.4%), nausea (13.7%), and asthenia (11.1%). The majority of cases occurred during cycles 1–3, with a peak occurrence at cycle 1 for all 4 TRAEs. Hypothyroidism was the only irTRAE seen in ≥5% of patients, and 94% of cases occurred between cycles 2 and 8, with a peak occurrence seen at cycle 4. irTRAEs that were seen in ≥1% of patients included diarrhea (4.1%), amylase increased (2.2%), aspartate aminotransferase increased (2.2%), alanine aminotransferase increased (1.8%), colitis (1.5%), hyperglycemia (1.5%), lipase increased (1.5%), adrenal insufficiency (1.1%), and hyperthyroidism (1.1%). No increase in the rate of TRAEs or irTRAEs was seen when changing to the 1000-mg Q6W dose.
Conclusions: When analyzed over the dMMR and MMRp EC safety population of the GARNET trial, dostarlimab has an acceptable safety profile with manageable AEs. irTRAEs and TRAEs low overall and were seen more frequently earlier in the time course of dostarlimab treatment.
Funding: GSK 213346; editorial support from Fishawack Health, funded by GSK.
Abstract previously presented at the Oncology Nursing Society 2021 Annual Meeting; submitted, with permission, on behalf of the original authors.