BACKGROUND:HLX26 is a novel, recombinant humanized anti-LAG-3 IgG4 monoclonal antibody that exhibits high affinity for LAG-3 and demonstrates that it can block LAG-3 and its ligand interaction and activate T cells in preclinical in vitro studies.
OBJECTIVE:These two phase I, dose-escalation studies evaluated the safety, tolerability, pharmacokinetics profile, and preliminary efficacy of HLX26 monotherapy, or in combination with serplulimab (PD-1 inhibitor), in patients with advanced/metastatic solid tumors or lymphomas.
PATIENTS AND METHODS:Adult patients with advanced/metastatic solid tumors that have failed or deemed clinically unsuitable for standard therapy, or lymphoma received different doses of HLX26 alone (at 60, 150, 300, 500, and 800 mg administered every 3 weeks [Q3W]) in the HLX26-001 study, or HLX26 plus serplulimab (HLX26 at 500, 800, and 1600 mg plus serplulimab (300 mg) administered Q3W) in the HLX26-002 study, respectively. The primary end points for both studies were the dose-limiting toxicities (DLT) and maximum tolerable dose (MTD).
RESULTS:As of 18 August 2023, with a median follow-up duration of 12.8 months, 26 patients were screened for the HLX26-001 study, 18 of whom were enrolled. As of 31 August 2023, with a median follow up duration of 6.0 months, 14 patients were screened for the HLX26-002 study, 9 of whom received HLX26 plus serplulimab. No DLT was observed, and the MTD was not reached for both studies. In the HLX26-001 study, 17 (94.4%) patients experienced at least one treatment-emergent adverse event (TEAE), most commonly proteinuria (n = 6, 33.3%) and hypercholesterolemia (n = 5, 27.8%). In the HLX26-002 study, all nine (100.0%) patients experienced TEAEs that were all treatment-related and predominantly mild in severity.
CONCLUSIONS:HLX26 was well-tolerated and safe at various doses as a single agent, and in combination with serplulimab for patients with advanced solid tumors and warrants further investigation.
TRIAL REGISTRATION:HLX26-001-ClinicalTrials.gov: NCT05078593; HLX26-002-ClinicalTrials.gov: NCT05400265.