Pomalidomide induced lupus type hypersensitivity reaction

Abstract

Multiple myeloma (MM) is a plasma cell disease characterized by a clonal proliferation of malignant plasma cells. Pomalidomide, a novel immunomodulating imide drug (IMiD), prolongs survival in relapsed or refractory cases. Cutaneous toxicity is one of the most common side effects of anti-cancer therapy that may even lead to discontinuation of treatment. We report a case of pomalidomide induced cutaneous lupus-like hypersensitivity reaction in a 75-year-old male diagnosed with MM. The patient relapsed on lenalidomide after 7 years. Pomalidomide and ixazomib were considered the next best treatment options. Treatment was complicated by a generalized rash (grade 3) after 2 cycles (3 weeks on and 1 week off cycle). Multiple pink, dusky plaques on the lower back and abdomen, some light pink and edematous areas on the chest, abdomen, neck, and hairline, and a few on arms were seen. The patient did not report pruritis. There was no involvement of the mucosa. Palms and soles were spared. No prior history of a rash with lenalidomide. A punch biopsy showed a moderate number of eosinophils within the inflammatory infiltrate, a finding which favored a lupus-type hypersensitivity reaction rather than true lupus erythematosus or leukemia cutis. Both medications were discontinued, and topical betamethasone was administered. The patient's symptoms resolved in 2 weeks. Ixazomib single-agent therapy was subsequently resumed without any adverse effects. It is essential to differentiate between disease progression itself vs. drug-induced lupus hypersensitivity reaction vs. systemic lupus erythematosus (SLE) vs. drug-induced hypersensitivity reaction. Therefore, all such lesions should always be biopsied. Our case study is unique because of the incongruent timeline and because it is unusual to expect such a reaction in a patient who has previously tolerated one such treatment. In our case, punch biopsy showed that the patient had a lupus-like hypersensitivity reaction. Pomalidomide was determined to be the most likely trigger preceding his presentation. Timely identification of the culprit drug is critical. The mainstay of management is to discontinue the drug. In severe cases, systemic steroids can be considered.

Keywords

• Multiple myeloma
• Rash
• Pomalidomide
• Ixazomib