A novel trial design used mosinutuzumab monotherapy first in frontline follicular lymphoma, adding lenalidomide only for patients without a complete response. This adaptive approach successfully spared about two-thirds of patients from the added toxicities of lenalidomide while still achieving very high overall efficacy.

A modified three-step-up dosing schedule for epcoritamab drastically reduced cytokine release syndrome (CRS) rates to 26%, with no severe events. This safety profile supports fully outpatient administration, making this highly effective regimen accessible to community practices without immediate hospital access.

Beyond approving the triplet combination, the positive Epcor FL1 trial data had a significant ripple effect. It solidified the drug's overall profile, leading to the conversion of its prior provisional (accelerated) approvals for monotherapy in follicular lymphoma and DLBCL into full, traditional approvals.

In follicular lymphoma, the treatment goal is durable remission with manageable toxicity, not necessarily a cure. Therefore, clinicians frequently prefer using a bispecific antibody first, reserving the more complex and toxic CAR-T cell therapy for transformed disease or after a bispecific fails.

Not all CD20-targeting bispecifics can be combined with rituximab. Mosunetuzumab binds the same epitope, causing competition. However, glofitamab and epcoritamab bind different epitopes, allowing for logical and potentially synergistic combinations with rituximab-based regimens.

Despite new therapies for follicular lymphoma (FL), bendamustine-rituximab (BR) will likely remain the community standard due to its simplicity. This may create a growing gap in treatment approaches between academic centers using novel agents and community practices favoring the familiar BR regimen.

The regimen's profound success in relapsed/refractory patients is not an endpoint, but a launchpad. It provides the rationale for the ongoing Epcor FL2 trial, which directly challenges standard chemoimmunotherapy and could establish a chemotherapy-free, bispecific-based combination as the new first-line standard of care.

Long-term follow-up from the pivotal epcoritamab trial reveals that 46% of DLBCL patients who achieve a complete remission maintain it at four years. This durability provides strong evidence that bispecific monotherapy, not just CAR-T, can be a curative treatment for a subset of patients.

The dramatic efficacy boost from adding epcoritamab suggests it's the primary driver of patient benefit, not just an adjunct. This shifts the conceptual framework, positioning the bispecific antibody as the new therapeutic backbone, with rituximab and lenalidomide as supportive agents.