Phase I study of ofatumumab (OFA) in Japanese patients (JPN pts) with relapsed or refractory chronic lymphocytic leukemia (CLL) and small lymphocytic lymphoma (SLL).

e18525 Background: OFA is a human IgG1 monoclonal antibody that recognizes a unique epitope encompassing the small and large loop of CD20. OFA was recently approved by the U.S. FDA for treatment of CLL refractory to fludarabine and alemtuzumab based on a pivotal study of a 2,000 mg dose. Methods: We conducted an open-label, nonrandomized, multicenter, phase I study to evaluate the tolerability, safety, efficacy and pharmacokinetics (PK) of OFA monotherapy in JPN pts with CD20-positive, relapsed/refractory CLL, SLL or follicular lymphoma. Pts received 300 mg of OFA at the 1st infusion, followed by 7 weekly infusions of 500 mg (level 1) or 1,000 mg (level 2). The primary endpoint was to determine toxicity including dose-limiting toxicity (DLT). Results: Baseline characteristics are summarized in the Table. All pts completed 8 planned doses. No DLT or serious Adverse Events (AEs) was observed. The investigator reported grade 3-4 AEs were grade 3 lymphopenia (n=1) and neutropenia (n=1). All pts had a grade 1-...