Safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity of a novel anti-TSLP bispecific antibody (GR2002) in healthy Chinese adults: A randomized, placebo-controlled phase 1 trial

BACKGROUND: GR2002 is a novel bispecific antibody targeting dual epitopes on thymic stromal lymphopoietin (TSLP). We aimed to assess the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and immunogenicity of GR2002 in healthy Chinese adults. METHODS: In this randomized, double-blind, placebo-controlled, dose-escalation, phase 1 trial of GR2002, healthy adults were enrolled and assigned to one of five dose cohorts. Within each cohort, participants were randomized (4:1) to receive a single subcutaneous dose of GR2002 (35, 70, 140, 280, or 420 mg) or placebo and were followed for 85 days. The primary endpoints included safety and tolerability. Secondary endpoints comprised PK, PD, and immunogenicity. RESULTS: Fifty eligible subjects were enrolled and randomized to receive either GR2002 (n = 40) or placebo (n = 10). A total of 92 treatment-emergent adverse events (TEAEs) were reported, with comparable incidence between the GR2002 and placebo groups. TEAEs were generally mild to moderate in severity and did not exhibit dose dependency. The most common treatment-related adverse event was upper respiratory tract infection, occurring in 7/40 (17.5%) participants in the GR2002 group and 2/10 (20%) in the placebo group. GR2002 displayed linear PK across the dose range tested, with a mean half-life ranging from 26.0 to 58.9 days. Dose-dependent reductions in serum TSLP levels from baseline were observed in the 140-420 mg dose groups. Anti-drug antibodies were detected in six subjects (15%) following GR2002 administration. CONCLUSIONS: Single-dose subcutaneous administration of GR2002 demonstrated favorable safety and tolerability, linear PK, and low immunogenicity. These findings warrant the subsequent clinical development of GR2002.