Graft-Versus-Host Disease in Multiple Myeloma Patients Treated With Daratumumab After Allogeneic Transplantation

Decrease in regulatory T cell (Tregs) has been linked to graft-versus-host disease (GVHD) after allogeneic hematopoietic cell transplantation (allo-HCT). The use of daratumumab poses a theoretical concern for GVHD flare because of its effects on Tregs and helper and cytotoxic T cells. In this multicenter retrospective study of relapsed multiple myeloma patients who received daratumumab after allo-HCT, we demonstrate low incidence of GVHD after daratumumab treatment. Introduction: Allogeneic hematopoietic cell transplantation (allo-HCT) represents an adoptive immunotherapy strategy for eliciting a graft-versus-myeloma, the effect for high-risk or relapsed multiple myeloma (MM). Allo-HCT recipients are at risk for graft-versus-host disease (GVHD) as well as associated increases in morbidity and mortality. Daratumumab, an anti-CD38 human immunoglobulin G1 kappa humanized monoclonal antibody, is used for treatment of MM. Daratumumab also affects CD38thorn nonmyeloma cells, including T cells, which mediate GVHD. The use of daratumumab after allo-HCT has not been well described, and its potential impact on GVHD is unknown. Patients and Methods: In a multicenter retrospective study, we evaluated incidence of GVHD in 34 patients with relapsed MM treated with daratumumab after allo-HCT. Results: Overall response to daratumumab (partial response or better) was 41% (95% confidence interval, 24-59). Five patients (15%) developed acute GVHD after daratumumab therapy; no chronic GVHD events were observed after daratumumab therapy. One of these 5 patients had a history of chronic GVHD and developed a flare of acute GVHD during daratumumab therapy. The remaining 4 patients did not have a history of GVHD before daratumumab. Conclusion: The incidence of GVHD after daratumumab was low and did not result in increased exacerbation of GVHD in patients with a history of GVHD.