Daratumumab for Refractory IgD Multiple Myeloma with Lung Cancer and Persistent Thrombocytopenia: a Case Report.

Background Immunoglobulin D multiple myeloma (IgD-MM) is a rare but aggressive disease. The safety and effectiveness of anti-CD38 monoclonal antibody (daratumumab) have not been known in either IgD-MM or MM complicated with secondary neoplasm. Methods A fragile IgD-MM patient had an aggressively relapsed disease concurrent with lung cancer and severe thrombocytopenia, which led to a dilemma for management. After a failure of ixazomib-based chemotherapy, a salvage therapy with daratumumab unexpectedly induced complete remission and platelet recovery, and the patient successfully proceeded to lung cancer surgery. Conclusions Our case indicates daratumumab is both safe and effective for refractory IgD-MM with severe complications.