Safety, tolerability, and pharmacokinetics of an anti-LAG-3 antibody SHR-1802 in patients with advanced solid tumors: a phase I dose-escalation and dose-expansion study

Abstract

Background: Lymphocyte-activation gene 3 (LAG-3), a checkpoint molecule contributing to immune suppressive microenvironment, is regarded as a promising target in cancer treatment. SHR-1802 is a novel anti-LAG-3 monoclonal antibody.

Objectives: To evaluate the safety, tolerability, pharmacokinetics, and antitumor activity of SHR-1802.

Design: A phase I dose-escalation and expansion trial of SHR-1802 in patients with advanced solid tumors.

Methods: Patients with confirmed advanced solid tumors who failed previous standard-of-care or for whom no effective therapy was available were enrolled to receive SHR-1802 once every 21-day cycle. Dose escalation was performed in an accelerated titration design followed by a 3 + 3 scheme at escalating doses from 0.3 to 10 mg/kg. On the basis of results from dose-escalation phase, one or two dose levels were expanded to establish the recommended phase II dose (RP2D). The primary end points were dose-limiting toxicity (DLT) and RP2D.

Results: Between 01 July 2020, and 07 September 2021, 28 patients were enrolled. No DLTs were observed, and all doses investigated were well tolerated. Treatment-related adverse events occurred in 20 patients (71.4%), all grade 1 or 2, with the most common ones being anemia (14.3%), asthenia (14.3%), electrocardiogram QT prolonged (14.3%), followed by increased blood fibrinogen (10.7%), infusion-related reaction (10.7%), and hypoalbuminemia (10.7%). No adverse event-related discontinuation occurred. Three patients died from adverse events, but none of the deaths were deemed related to study treatment. SHR-1802 exposure enhanced with the increasing doses in a greater than dose-proportional manner over the investigated dose range. The disease control rate was 32.0% (95% CI 14.9%-53.5%). The median progression-free survival was 2.0 months (95% CI 1.2-6.1).

Conclusions: SHR-1802 demonstrated a tolerable safety profile and preliminary antitumor activity in patients with advanced solid tumors. Further studies with larger sample size and in combination forms are warranted for future clinical application.

Registration clinicaltrialsgov: NCT04414150.

Keywords: LAG-3; SHR-1802; immune checkpoint inhibitor; immune regulation; monoclonal antibody.