Safety, antitumor activity, and pharmacokinetics of dostarlimab, an anti-PD-1, in patients with advanced solid tumors: a dose-escalation phase 1 trial

Cancer Chemother Pharmacol. 2022 Jan;89(1):93-103. doi: 10.1007/s00280-021-04358-3. Epub 2021 Nov 8.


Purpose: New immuno-oncology therapies targeting programmed cell death receptor 1 (PD-1) have improved patient outcomes in a broad range of cancers. The objective of this analysis was to evaluate the PK, pharmacodynamics (PDy), and safety of dostarlimab monotherapy in adult patients with previously-treated advanced solid tumors who participated in parts 1 and 2A of the phase 1 GARNET study.

Methods: Part 1 featured a 3 + 3 weight-based dose-escalation study, in which 21 patients received dostarlimab 1, 3, or 10 mg/kg intravenously every 2 weeks. The 2 fixed-dose nonweight-based dosing regimens of dostarlimab 500 mg every 3 weeks (Q3W) and 1000 mg every 6 weeks (Q6W) were evaluated using a modified 6 + 6 design in part 2A (n = 13). In parts 1 and 2A, treatment with dostarlimab could continue for up to 2 years or until progression, unacceptable toxicity, patient withdrawal, investigator's decision, or death.

Results: The dostarlimab PK profile was dose proportional, and maximal achievable receptor occupancy (RO) was observed at all dose levels in the weight-based and fixed-dose cohorts. Trough dostarlimab concentration after administration of dostarlimab 500 mg Q3W was similar to that after dostarlimab 1000 mg Q6W, the values of which (≈40 µg/mL) projected well above the lowest dostarlimab concentration required for full peripheral RO. No dose-limiting toxicities were observed.

Conclusions: Dostarlimab demonstrated consistent and predictable PK and associated PDy. The observed safety profile was acceptable and characteristic of the anti-PD-1 drug class.

Trial registration:, NCT02715284. Registration date: March 9, 2016.

Keywords: Advanced cancer; Dostarlimab; Phase 1 clinical trial; Programmed cell death receptor 1; TSR-042.

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