A phase I, dose-escalation study of ADG106, a fully human anti-CD137 agonistic antibody, in subjects with advanced solid tumors or relapsed/refractory non-Hodgkin lymphoma.

Abstract

3105 Background: ADG106 is a fully human agonistic anti-CD137 monoclonal IgG4 antibody, targeting a unique epitope of CD137 with novel mechanism of actions for CD137 agonism, CD137 ligand antagonism and potent cross-linking via FcgRIIb. This phase 1 study was conducted to assess its safety, tolerability, pharmacokinetic (PK) profile, immunogenicity and preliminary efficacy. Methods: Eligible patients with age 18 to 75, ECOG ≤1, measurable lesion received intravenous infusion of ADG106 every 3 weeks for a maximum of 24 months. Accelerated titration was applied in 0.1mg/kg dose level and traditional Fibonacci 3+3 method was applied in 0.5, 1.5, 3.0, 5.0 and 10.0 mg/kg dose levels. A dose-expansion cohort will be started for dose levels that have been proved tolerable and with evidence of clinical or biological activity. Results: Data cutoff at Jan 17 2020, 15 patients [5 adenoid cystic carcinoma (ACC), 5 non-small cell lung cancer (NSCLC), 3 nasopharyngeal carcinoma, 1 malignant pleural mesothelioma and 1 follicular lymphoma] were enrolled and received treatment: 0.1mg/kg (n = 1), 0.5mg/kg (n = 3), 1.5mg/kg (n = 5), 3mg/kg (n = 3), and 5mg/kg (n = 3). Of these 15 patients, 6 with ongoing treatment, 9 discontinued (8 progression disease, 1 lack of clinical benefit). Medium treatment duration was 2 cycles (range 2-8). No dose limiting toxicities were observed. Seven (47%) patients experienced treatment-related AEs (TRAEs): rash (13%), pruritus (13%), nausea (7%), pyrexia (7%), hemoptysis (7%), mouth ulceration (7%), vomiting (7%), chest discomfort (7%), LDH increased (7%). All TRAEs were grade 1, no grade ≥3 occurred. One serious adverse event (anemia, not related) was observed. Pharmacokinetic analysis of ADG106 showed a half-life ranging from 5~10 days, with dose-dependent increase of systemic exposure. Treatment induced anti-drug antibodies were developed in 3 (20%) patients. No objective response was observed among the 14 evaluated patients. Disease control rate was 57% (8 stable disease), tumor shrinkage was observed in 3 (21%) patients (2 ACC, 1 NSCLC). Conclusions: ADG106 is safe and tolerable at doses up to 5 mg/kg in solid tumors and non-Hodgkin lymphoma. The dose expansion cohorts have started at selected doses. Clinical trial information: NCT03802955 .