Article Text
Abstract
Background Dostarlimab is a humanized programmed death 1 (PD-1) receptor monoclonal antibody that blocks interaction with the ligands PD-L1 and PD-L2. Dostarlimab is approved as a monotherapy in adult patients (pts) with mismatch repair deficient (dMMR; US) or dMMR/microsatellite-instability high (EU) recurrent or advanced endometrial cancer that has progressed progressing on or following prior treatment with a platinum-containing regimen. GARNET is a phase 1 study assessing antitumor activity and safety of dostarlimab monotherapy in pts with solid tumors.
Methods Pts with dMMR solid tumors, mismatch repair proficient endometrial cancer, and non-small cell lung cancer that progressed on or after prior therapy received 500 mg of dostarlimab IV every 3 weeks (Q3W) for 4 cycles, then 1000 mg IV every 6 weeks (Q6W) for up to 2 years or until disease progression or discontinuation. Here, we report TRAEs by cycle.
Results A total of 515 pts were included. Of these pts, 60 (11.7%) experienced TRAEs leading to treatment interruption, and 25 (4.9%) experienced TRAEs leading to discontinuation. TRAEs of any grade with overall incidence of ≥10% of pts are shown (table 1). The majority of TRAEs occurred during cycles 1–3, with highest incidence during cycle 1. Grade 3 or 4 TRAEs were rare; those seen in ≥1% of pts are shown. Immune-related (ir) TRAEs of any grade with overall incidence of ≥2% of pts are shown. Most cases (96.9%) of irTRAEs occurred during cycles 1–8. The peak incidence of hypothyroidism occurred during cycle 4; in addition, frequency was increased during cycles 5–8, compared with cycles 1–4. No deaths were attributed to dostarlimab.
Time course of adverse events in the GARNET trial
Conclusions No new safety signals were detected with dostarlimab compared to other anti–PD-1 inhibitors. Most TRAEs were low grade. The majority of TRAEs and grade ≥3 TRAEs occurred in the first 3 cycles (first 12 weeks), but some cases occurred later, suggesting a need for ongoing monitoring. Few increases in the incidence of TRAEs were seen during cycle 5 following the transition to the 1000-mg Q6W dosing schedule; the TRAEs with increased incidence after the transition were fatigue and lipase increased. An increase in the frequency of the irTRAE hypothyroidism was seen after transitioning to the 1000-mg Q6W schedule.