Daratumumab is well tolerated in patients with AL amyloidosis when used with appropriate pre- and post-infusion medications.
Daratumumab leads to rapid and deep hematologic responses in previously treated patients with AL amyloidosis.
Daratumumab, a monoclonal CD 38 antibody, is approved in the treatment of myeloma, but its efficacy and safety in AL amyloidosis has not been formally studied. This prospective phase II trial of daratumumab monotherapy for the treatment of light chain amyloidosis (AL) was designed to determine the safety, tolerability, and hematologic and clinical response. Daratumumab 16 mg/kg was administered by intravenous infusion once weekly for weeks 1-8, every 2 weeks for weeks 9-24, and every 4 weeks thereafter until progression or unacceptable toxicity, for up to 24 months. Twenty-two patients with previously treated AL were enrolled. The majority of the patients had received high-dose melphalan and stem cell transplantation and/or treatment with a proteasome inhibitor. The median time between prior therapy and trial enrollment was 9 months (range, 1-180). No grade 3-4 infusion-related reactions occurred. The most common grade ≥3 adverse events included respiratory infections (n=4, 18%) and atrial fibrillation (n=4, 18%). Hematologic complete and very good partial response occurred in 86% of patients. The median time to first and best hematologic response was 4 weeks and 3 months respectively. Renal response occurred in 10 (67%) of 15 patients with renal involvement and cardiac response occurred in 7 (50%) of 14 patients with cardiac involvement. In summary, daratumumab is well tolerated in patients with relapsed AL amyloidosis and leads to rapid and deep hematologic responses and organ responses. This trial was registered at www.clinicaltrials.gov as NCT02841033.