YH003 is a recombinant, humanized agonistic anti-CD40 IgG2 monoclonal antibody (mAb). We have primarily completed (with the RP2D identified) a Phase I clinical trial in Australia to evaluate the safety, tolerability, efficacy and pharmacokinetics of YH003 in combination with toripalimab in patients with advanced solid tumors. Taken together, the available pre-clinical data and data from the Phase I clinical trial demonstrated a favorable safety and efficacy profile of YH003. Pre-clinical data also show robust anti-tumor activities of YH003 in combination with PD-1 mAbs. We believe YH003 is a potentially first-in-class or best-in-class anti-CD40 antibody.
As of the May 31, 2021 data cut-off date, among the 17 patients evaluated, two experienced Grade 3 drug related adverse events (TRAEs), eight had Grade 2 AEs including one Grade 2 increased amylase at 0.1 mg/kg dose level related to toripalimab, one Grade 2 hepatitis at 0.3 mg/kg dose level related to YH003 and toripalimab and six infusion reactions at 1.0 mg/kg dose level related to YH003. One Grade 3 TEAE (Transaminitis) related to YH003 was reported at 1.0 mg/kg dose level which led to permanent treatment discontinuation and met protocol defined DLT criteria and one Grade 3 TEAE (lipase increase) was reported at 0.1 mg/kg dose level which was only related to toripalimab. No drug related SAE and AE leading to death occurred. We are initiating a Phase II MRCT of YH003 in the United States and Australia. We received the IND approval from the FDA in June 2021 and are applying for CTN/IND approval from the Taiwan FDA and the NMPA. In addition, we plan to apply for a Phase I dose escalation trial in Australia to evaluate the safety, tolerability, preliminary efficacy and pharmacokinetics of YH001 and YH003 in combination with toripalimab in patients with advanced solid tumors. We will also further explore the expansion of YH003 for the treatment of other solid tumor indications.