A phase 1/2 trial of ublituximab,a novel anti‐CD20 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‐CD 20 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 (AE s) occurred. The most common AE s 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 AE s 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.