Polatuzumab vedotin or pinatuzumab vedotin plus rituximab in patients with relapsed or refractory non-Hodgkin lymphoma: final results from a phase 2 randomised study (ROMULUS)

Background Antibody-drug conjugates (ADCs) polatuzumab vedotin (pola) and pinatuzumab vedotin (pina) showed clinical activity and tolerability in phase 1 trials. The aim of this multicentre, open-label, phase 2 study was to compare rituximab plus pola (R-pola) or pina (R-pina) in patients with relapsed or refractory diffuse large B-cell lymphoma and follicular lymphoma. Methods In this phase 2 randomised study at 39 investigational sites in six countries, patients were randomly assigned (1: 1), by use of a dynamic hierarchical randomisation scheme, to receive R-pola or R-pina (375 mg/m(2) rituximab plus 2.4 mg/kg ADCs) every 21 days until disease progression or unacceptable toxicity up to 1 year. Treatment allocations were not masked to the investigator, patients or sponsor after the patients were enrolled and randomly assigned. The primary objectives were safety and tolerability, and antitumour response. The study is registered with ClinicalTrials. gov, number NCT01691898, and is closed to accrual. Findings 81 patients with diffuse large B-cell lymphoma and 42 with follicular lymphoma were recruited between Sept 27, 2012, and Oct 10, 2013, and were assigned to treatment. 81 patients with diffuse large B-cell lymphoma and 41 patients with follicular lymphoma were eligible for analysis. Of the 42 patients with diffuse large B-cell lymphoma who received R-pina, 25 (60%, 95% CI 43-74) achieved an objective response and 11 (26%, 95% CI 14-42) achieved a complete response. Of the 39 patients in this cohort who received R-pola, 21 (54%, 95% CI 37-70) achieved an objective response, and eight (21%, 95% CI 9-36) achieved a complete response. Of the 21 patients in the follicular lymphoma cohort who received R-pina, 13 (62%, 95% CI 38-82) achieved an objective response, and one (5%, 95% CI 0.1-24) achieved a complete response. Of the 20 patients in this cohort who received R-pola, 14 (70%, 95% CI 46-88) achieved an objective response, and nine (45%, 95% CI 23-68) achieved a complete response. In the diffuse large B-cell lymphoma cohort, grade 3-5 adverse events occurred in 33 (79%) of 42 patients receiving R-pina (most common were neutropenia [29%] and hyperglycaemia [10%]; nine [21%] grade 5 adverse events, five of which were infectionrelated), and in 30 (77%) of 39 patients receiving R-pola (most common were neutropenia [23%], anaemia [8%] and diarrhoea [8%]; no grade 5 adverse events). In the follicular lymphoma cohort, grade 3-5 adverse events occurred in 13 (62%) of 21 patients receiving R-pina (most common were neutropenia [29%] and hyperglycaemia [14%]; no grade 5 adverse events) and in ten (50%) of 20 patients receiving R-pola (most common were neutropenia [15%] and diarrhoea [10%]; one grade 5 adverse event). Interpretation R-pina and R-pola are potential treatment options in patients with relapsed or refractory diffuse large B-cell lymphoma and follicular lymphoma. Pola was selected by the study funder for further development in nonHodgkin lymphoma, partly because of longer durations of response than pina, and an overall benefit-risk favouring R-pola.