e13007 Background: Human epidermal growth factor receptor 2 (HER2) is an effective therapeutic target for breast and gastric cancer. A166 is an antibody-drug conjugate composed of a novel cytotoxic drug (monomethyl auristatin F derivative ) site-specifically conjugated to transtuzumab sequence via a stable protease-cleavable valine citrulline linker, which has a DAR (Drug Antibody Ratio) of Better efficacy were observed in preclinical CDX and PDX studies including HER2 low expression and T-DM1 resistant models while toxicity studies demonstrated a good safety profile in cynomolgus monkey. Methods: Patients with HER2-expressing or amplified advanced solid tumors refractory to standard therapies were recruited. A modified Fibonacci 3 + 3 dose-escalation design was employed with 7 dose levels (0.1, 0.3, 0.6, 1.2, 2.4, 3.6, and 4.8 mg/kg every 3 weeks). Safety analyses included all patients. PK and antitumor activity were also assessed. Primary objectives in dose escalation are safety and tolerability and determination of maximum tolerated dose (MTD) and recommended Phase 2 dose. Results: As of October 1, 2019 among 19 patients (breast cancer, colorectal cancer and gastric cancer)treated,no one experienced dose-limiting toxicity. No maximum tolerated dose was determined until 4.8mg/kg dose level. Grade≥3 adverse event was reported for 4 patient as neutropenia、anemia、Hyponatremia and Hypophosphatemia. Notably, 36.8% (n = 7) of patients experienced dry eye, as well as corneal epitheliopathy, and 2 patients withdraw from the study due to grade 2 corneal epitheliopathy. In 3.6 and 4.8 mg/kg groups, 6 patients were evaluable for tumor response, including 3 with partial response, 2 with stable disease. A166 exposure increased with the increase of dose, and extremely low exposure of free toxin and toxin-linker conjugates were observed; t1/2 was 8.29 days at the 4.8mg/kg. Conclusions: A166 showed an acceptable safety profile and promising anti-tumor activity in patients with HER2-expressing advanced solid tumors. Clinical trial information: CTR20181301 .
Phase 1 study of anti-epidermal growth factor receptor monoclonal antibody in patients with solid tumors
