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.