(PA-411) Daratumumab as Post-ASCT Maintenance in Multiple Myeloma Patients with Lenalidomide Intolerance/toxicity: Results from a Single Center over the Last 5 Years

Maintenance therapy after autologous stem cell transplantation (ASCT) in multiple myeloma (MM) improves progression-free survival, with lenalidomide being the most commonly used agent. However, its use can be limited by intolerance or toxicity. Daratumumab, an anti-CD38 antibody with proven efficacy in MM, could be an alternative in these cases. This study describes the experience of a single center using daratumumab as maintenance therapy in patients not eligible for lenalidomide over the past five years. The objetive of this study is to evaluate the efficacy of daratumumab maintenance in terms of response and disease control in MM patients post-ASCT with intolerance/toxicity to lenalidomide.

Methods:

A retrospective, descriptive, single-center study (HU Príncipe de Asturias, Madrid) of MM patients receiving daratumumab maintenance post-ASCT from April 2020 to May 2025. Demographic, clinical, laboratory data, and treatment response were analyzed. Clinical management was conducted according to the recommendations of the Spanish Myeloma Group.

Results:

Seven MM patients who received daratumumab maintenance after ASCT due to lenalidomide intolerance or toxicity were included. The median age was 58 years (interquartile range [IQR] 53.5–60), with a female predominance (57.1%). High-risk cytogenetics were present in 85.7%, and 71.4% were ISS-R stage 2. The most common MM subtypes were IgG Kappa and Kappa light chain (28.6% each).

Pre-ASCT treatment included bortezomib- and daratumumab-based regimens. Daratumumab was administered prior to transplantation in 42.9% of patients. Conditioning regimens were MEL-200 (71.4%) or BUMEL (42.9%). At day +100 post-ASCT, 3 patients (42.9%) were minimal residual disease (MRD) positive, 2 were negative, and 2 had no available information.

The median duration of daratumumab maintenance was 24 months (IQR 18–28). At the last evaluation, 3 patients (42.9%) remained MRD positive and 4 had no available data. No biochemical progression was detected during treatment in any case. Three patients completed therapy without evidence of progression to date.

Conclusions: In our experience, daratumumab as post-ASCT maintenance therapy in MM patients with lenalidomide intolerance/toxicity was associated with good disease control, no biochemical progression during follow-up, and adequate tolerance. These results support its use as a safe and effective alternative in this clinical context.