Rituximab Biosimilar Combined with Pegylated Interferon α-2b in Patients with Untreated Advanced Indolent B-Cell NHL

The preliminary results of a phase 2 study indicate that the combination of rituximab biosimilar plus pegylated interferon α-2b was well-tolerated and yielded responses in newly diagnosed advanced indolent B-cell NHL.

Based on the hypothesis that pegylated interferon α-2b (peg-IFN-α2b) may synergize with rituximab, a multicenter, single-arm phase 2 study (NCT04246359) evaluated the efficacy and safety of combination rituximab biosimilar plus peg-IFN-α2b in patients with treatment-naïve indolent B-cell non-Hodgkin lymphoma (NHL); the results of this study were presented at the 2021 American Society of Hematology Annual Meeting.

From January 2020 to July 2021, patients aged 18 to 80 years with newly diagnosed indolent B-cell NHL including follicular lymphoma (FL; grade 1-2, 3a) and marginal zone lymphoma, Eastern Cooperative Oncology Group performance status ≤2, ≥1 measurable or evaluable lesions, hepatitis B surface antigen positivity with hepatitis B virus (HBV) DNA load <3000 IU/mL prior to study, and serum alanine transaminase level of <5 times the upper limit of normal were enrolled in the study from 6 institutions in China. Eligible patients received induction treatment of rituximab biosimilar (375 mg/m2 intravenous infusion day 1) plus peg-IFN-α2b (135 μg, days 1, 8) every 21 days for 6 cycles. Patients who responded to treatment received rituximab (every 2 months) plus peg-IFN-α2b (every month) maintenance at the dose described for up to 2 years until disease progression and intolerance. The primary end point was objective response rate (ORR) by investigator assessment; key secondary end points included time to response, duration of response, progression-free survival (PFS), overall survival (OS), HBV DNA load clearance, and safety.

A total of 52 patients were enrolled in the study. At cutoff date, the median age of the study population was 54 years; the majority (54.5%) were female, 46.3% had grade 1/2 FL, 35.2% had mucosa-associated lymphoid tissue, 14.8% had grade 3a FL, and 40.7% of patients had a Follicular Lymphoma International Prognostic Index score ≥3.

The efficacy analysis population included 50 patients. Per investigator assessment, an ORR of 62.0% was achieved, including 19 complete responses (CRs). By lymphoma type, ORR was 58.3% (14/24) in the grade 1 to grade 3 FL cohort (CR, 29.2%), 75.0% (6/8) in the grade 3a FL cohort (CR, 62.5%), and 61.1% (11/18) in the mucosa-associated lymphoid tissue cohort (CR, 38.9%). Median HBV DNA load clearance time was 1.8 months, and no HBV reactivations were reported. At median follow-up of 6.2 months, median OS, PFS, and duration of response were not reached; 6-month OS was 96.7% and the 6-month PFS rate was 85.3 ± 6.1%. The median time to response was 3.0 months.

Treatment-emergent adverse events (TEAEs) were predominantly hematologic toxicities (>30%), including neutropenia (63.5%), anemia (34.6%), and thrombocytopenia (28.8%). Nonhematologic TEAEs (>10%) were fever (28.8%), transaminase elevated (28.8%), fatigue (26.9%), and infusion reaction (17.4%). The most common grade 3/4 TEAEs (>5%) were neutropenia (17.3%) and anemia (7.7%). No treatment-related deaths occurred in the study.

Based on these results, it was concluded that the combination of rituximab biosimilar plus peg-IFN-α2b was well-tolerated and yielded responses in newly diagnosed advanced indolent B-cell NHLs.

Source: Yan G, Wu J, Huang Y, et al. Rituximab biosimilar combined with pegylated interferon α-2b in patients with untreated advanced indolent B-cell non-Hodgkin’s lymphoma: preliminary results from a multicenter, single-arm, phase II study. Blood. 2021;138(suppl_1):1359.