Safety, tolerability, pharmacokinetics, and antitumour activity of oleclumab in Japanese patients with advanced solid malignancies: a phase I, open-label study

Background Cluster of differentiation (CD) 73-targeted immunotherapy and CD73 inhibition may reduce adenosine production, which can augment the host and/or immunotherapy response to tumours. We aimed to assess the safety and tolerability, pharmacokinetics, and antitumour activity of oleclumab, an anti-CD73 monoclonal antibody, in adult Japanese patients with advanced solid malignancies resistant to standard therapy. Methods In this phase I, single-centre, open-label study, patients received oleclumab 1500 mg (Cohort 1) or 3000 mg (Cohort 2) intravenously every 2 weeks. Results In total, six patients were enrolled in the study (three in each cohort), and all six patients received the study treatment. The median patient age was 56.0 years and 4/6 were males. All patients (100%) reported adverse events (AEs) during the study; five (83.3%) patients reported AEs related to the study treatment. One (16.7%) patient reported a Grade 3 AE (neutrophil count decreased) that was not related to the study treatment. No AEs with an outcome of death were reported, and no patients reported AEs or serious AEs leading to oleclumab discontinuation/dose interruption. No dose-limiting toxicities were reported, and no patient discontinued due to an AE related to the study treatment. Oleclumab exposure increased dose proportionally. No patient achieved disease control at 8 weeks, and all six patients developed progressive disease. Conclusions Oleclumab was well tolerated in adult Japanese patients with advanced solid malignancies and no unexpected safety concerns were raised; oleclumab exposure increased with dose. Future studies on combination therapy with other agents are warranted.