Early study but more supportive data for bispecific antibodies in this setting. Community oncology will soon have an array of options and understanding/managing toxicities will be important for this class of drugs.
Mosunetuzumab is a bispecific antibody targeting CD20 and CD3 that redirects T cells to engage and eliminate malignant B cells and is being developed for relapsed or refractory (R/R) B-cell non-Hodgkin lymphomas (B-NHLs).
This first-in-human trial (ClinicalTrials.gov identifier: NCT02500407) evaluated the safety and tolerability and efficacy of mosunetuzumab in patients with R/R B-NHL and established the recommended phase II dose. Data from dose escalation are presented. Single-agent mosunetuzumab was administered intravenously in 3-week cycles, at full dose in cycle 1 day 1 (group A) or with ascending (step-up) doses during cycle 1 on days 1, 8, and 15 (group B), for eight or 17 cycles on the basis of tumor response.
Two hundred thirty patients were enrolled. Doses up to 2.8 mg and 60 mg were assessed in groups A and B, respectively; maximum tolerated dose was not exceeded. In group B (n = 197), common adverse events (≥ 20% of patients) were neutropenia (28.4%), cytokine release syndrome (27.4%), hypophosphatemia (23.4%), fatigue (22.8%), and diarrhea (21.8%). Cytokine release syndrome was mostly low-grade (grade ≥ 3: 1.0%) and mainly confined to cycle 1. Across the doses investigated (group B), best overall response rates were 34.9% and 66.2% in patients with aggressive and indolent B-NHL, respectively, and complete response rates were 19.4% and 48.5%. Among patients with a complete response, the median duration of response was 22.8 months (95% CI, 7.6 to not estimable) and 20.4 (95% CI, 16 to not estimable) in patients with aggressive and indolent B-NHL, respectively.
Mosunetuzumab, administered with step-up dosing, has a manageable safety profile and induces durable complete responses in R/R B-NHL. The expansion stage of the study is ongoing at the dose level of 1/2/60/60/30 mg selected for further study.
For transplant-eligible patients with Mantle Cell Lymphoma, Obinutuzumab showed superior efficacy compared to Rituximab. These patients are uncommon, but the results of this study show that in this context O seems to beat R in every aspect, including a 5-yr PFS of 82.8 vs 66.6%, which is striking. I would consider this option for the appropriate patient.
This combination had impressive results but led to a high rate of ventricular arrythmias (9%), hence the combination is not recommended. Another study with the combination and rituximab was also suspended, the etiology of the higher rate of Vent arrhythmias is not known. This combination in another lymphoid malignancies did not lead to that rate of toxicity.
Final results from the ASPEN study confirm the strong long-term superiority of zanubrutinib over ibrutinib in symptomatic WM. While overall survival (OS) and progression-free survival (PFS) end-points are still to be reached, demonstrating the good prognosis of this disease, toxicities and response rates are much better with zanubrutinib. This is a cat-1 indication oof NCCN and a compelling option for use in this population.
There are too many options for DLBCL now with monoclonal antibodies, bispecific and CAR-T therapy, but in frail patients, this might be an option. Tafatistamab with lenalidomide had higher ORR (55vs 50) and CR( 37 vs 27%) but this is comparing different trials, and this trial had mostly elderly pts, I do feel tafatistamab is fairly well tolerated though. But when in doubt this seems to be a fair option.
Speaking of tafatistamab, it seems it is fairly tolerable in first line with almost 75% CR added to RCHOP, adding lenolidomie 86% CR, but this is a phase 1b. Awaiting phase 3 data, we may have another first line option or may the first line option.
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