Results from a phase 2 trial (ClinicalTrials.gov Identifier: NCT01190449) assessing the use of ofatumumab monotherapy in patients with untreated, low- or intermediate-risk, advanced-stage follicular lymphoma (FL) were recently published in the British Journal of Haematology.
Rituximab monotherapy has demonstrated efficacy in treatment-naive patients with asymptomatic, advanced-stage FL, but researchers hypothesized that ofatumumab might provide a greater advantage in this patient population. In this study, they evaluated the safety and efficacy of ofatumumab, a second generation, humanized, IgG1 kappa type I monoclonal antibody, as a single agent.
The researchers enrolled 51 patients with measurable, previously untreated FL that was stage III or IV or in bulky stage II and that was identified as low- or intermediate-risk disease by the Follicular Lymphoma International Prognostic Index. Patients received 4 weekly doses of either 500 mg (15 patients) or 1000 mg (36 patients) ofatumumab followed by 4 additional doses given once every 8 weeks on an extended induction schedule.
The overall response rate in evaluable patients receiving 1000 mg doses was 84%. Median progression-free survival was 1.9 years, and median response duration was 23.7 months. In patients receiving 500 mg doses, the overall response rate was 60%, median progression-free survival was 1.9 years, and median duration of response was 16.5 months.
There were no grade 4 infusion reactions or grade 3 or 4 infections, and the discontinuation rate due to toxicity was 6% overall.
The extended induction dosing schedule was found to be well tolerated and was active as upfront treatment. However, the authors concluded that “[ofatumumab] does not appear superior to either rituximab or obinutuzumab at the doses and extended dosing schedule used in this study.”
1. Rosenbaum CA , Jung SH, Pitcher B, et al. Phase 2 multicentre study of single-agent ofatumumab in previously untreated follicular lymphoma: CALGB 50901 (Alliance) [published online February 5, 2019]. Br J Haematol. doi: 10.1111/bjh.15768