Objectives: CD26 is a transmembrane glycoprotein with dipeptidyl peptidase IV activity that is overexpressed in malignant pleural mesothelioma (MPM). We performed a phase I study to determine the maximum tolerated dose, pharmacokinetics, and antitumor activity of YS110, a monoclonal antibody to CD26, in Japanese patients with MPM intolerant of or refractory to prior standard therapies.
Material and methods: The study was designed as an open-label, 3 + 3 dose-escalation, phase I trial. Patients were sequentially assigned to three dosing cohorts (2, 4, or 6 mg/kg). Each 6-week treatment cycle consisted of YS110 administration weekly for 5 weeks followed by a 1-week rest period. Treatment was continued until disease progression, death, or intolerable toxicity. Corticosteroid, antihistamine, and acetaminophen administration before each infusion was adopted to limit infusion-related reactions (IRRs).
Results: Nine Japanese patients (seven men and two women, mean age of 62.2 years), three in each dosing cohort, were enrolled in the study. No patient developed a dose-limiting toxicity. Adverse events of grade 3 or 4 developed in seven patients, with the most common such event being a decreased lymphocyte count. Two patients had mild or moderate IRRs. The serum concentration of YS110 increased in a dose-dependent manner. Among seven patients evaluable for tumor response, four showed stable disease and one achieved a partial response.
Conclusions: YS110 showed promising antitumor efficacy and was generally well tolerated in Japanese patients with advanced MPM at doses of up to 6 mg/kg. YS110 will be tested at 6 mg/kg in a subsequent phase II study.
Keywords: CD26; Japanese; Malignant mesothelioma; Phase I; YS110.
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