Background and Importance Follicular B-lymphoma (FL) is an indolent lymphoid neoplasm derived from germinal centre mutated B-cells with a nodular or follicular histological pattern. Approximately 2–3% of patients will transform their neoplasm to diffuse large B-cell lymphoma (DLBCL). Epcoritamab-bysp (EPKINLY®) is a bispecific IgG1 antibody designed to simultaneously bind to CD3 on T-cells and CD20 on B-cells, and induces T-cell-mediated killing of CD20+ cells.

Aim and Objectives The aim of this study is to evaluate the efficacy and safety of epcoritamab-bysp in a patient with LF refractory to previous lines.

Material and Methods Retrospective study of a clinical case in which we follow-up a patient with Relapse/Refractory FL under treatment with epcoritamab-bysp. Administration was done in the lower abdomen or thigh and at a different site each time it was administered. Data were obtained using the digitised clinical history (Diraya) and the electronic chemotherapy or immunotherapy prescription programme (Oncofarm).

Results We present the case of a 57-year-old woman, 48.8 kg and 153 cm. Diagnosed in August 2020 with stage IV FL without B symptoms. FL was refractory to the first two lines of treatment (1L:R-CHOP, 2L:R-ESHAP), as well as to a clinical trial based on CAR-T therapy. In May 2023, expanded use of epcoritamab-bysp in monotherapy with weekly subcutaneous administration in C1 with dose step-up (0.16, 0.8, 48 mg); every 2 weeks C4–9 (48 mg), every 4 weeks from C10 to progression (48 mg) was decided. In all immunotherapy sessions the patient was admitted for 24h due to risk of severe adverse reactions (CRS or ICANS). In the second administration (0.8mg) of epcoritamab-bysp the patient had a CRS:G1, so in the administration of the first target dose (48 mg) 3ªweek of C1, the dose was reduced to 50% (24 mg). Even so, the patient had to be treated with IV tocilizumab (8mg/kg) by CRS: G2 and was admitted for observation for 48h. From C2 onwards, there were no further incidents. Regarding the clinical evolution of the LF PET-CT scan, a partial metabolic response (Deauville:4) was observed with respect to the previous study.

Conclusion and Relevance Despite the need for extended study time to evaluate the clinical benefit and safety in real clinical practice of epcoritamab-bysp in patients with FL or DLBCL, this immunotherapy offers an innovative mechanism of action and an interesting alternative for patients with non-Hodgkin’s lymphoma refractory to conventional therapies.

Conflict of Interest No conflict of interest.