A phase 1/2 trial of ublituximab, a novel anti‐ <scp>CD</scp> 20 monoclonal antibody, in patients with B‐cell non‐Hodgkin lymphoma or chronic lymphocytic leukaemia previously exposed to rituximab

This phase 1/2 study evaluated the safety, pharmacokinetic behavior and anti-tumour activity of ublituximab, a unique type I, chimeric, glycoengineered anti-CD20 monoclonal antibody, in rituximab-relapsed or -refractory patients with B-cell non-Hodgkin lymphoma (B-NHL) or chronic lymphocytic leukaemia (CLL). Induction therapy (doses of 450-1200 mg) consisted of 4 weekly infusions in cycle 1 for NHL and 3 weekly infusions in cycles 1 and 2 for CLL. Patients received ublituximab maintenance monthly during cycles 3-5, then once every 3 months for up to 2 years. Enrolled patients with B-NHL (n = 27) and CLL (n = 8) had a median of 3 prior therapies. No dose-limiting toxicities or unexpected adverse events (AEs) occurred. The most common AEs were infusion-related reactions (40%; grade 3/4, 0%); fatigue (37%; grade 3/4, 3%); pyrexia (29%; grade 3/4, 0%); and diarrhoea (26%; grade 3/4, 0%). Common haematological AEs were neutropenia (14%; grade 3/4, 14%) and anaemia (11%; grade 3/4, 6%). The overall response rate for evaluable patients (n = 31) was 45% (13% complete responses, 32% partial responses). Median duration of response and progression-free survival were 9·2 months and 7·7 months, respectively. Ublituximab was well-tolerated and efficacious in a heterogeneous and highly rituximab-pre-treated patient population.