Lenalidomide Desensitisation for Delayed Cutaneous Reaction: A Case Series and Review of the Literature.

Lenalidomide is commonly used for treatment of multiple myeloma (MM) as well as other hematological disorders. Cutaneous adverse reactions occur frequently and withholding lenalidomide treatment may have implications for prognosis.To evaluate the role of lenalidomide desensitization in patients with cutaneous adverse reactions.A retrospective review of patients referred for lenalidomide desensitization between May 2019 and May 2022 at a tertiary hospital. All patients underwent a 6-week outpatient desensitization with premedication.There were 12 patients: 10 males and 2 females with a median age of 65 years. All had MM with autologous stem cell transplantation and lenalidomide 10 mg daily added for maintenance therapy. Most patients (n = 8) had a generalized maculopapular exanthem with or without pruritus. All patients had delayed cutaneous reactions; the median time to onset was 14 days (range 2-28 d). Six patients tolerated desensitization: 5 on the first attempt and 1 after 3 attempts and supplementary oral prednisolone. Four patients underwent multiple (≤3) attempts at desensitization owing to breakthrough symptoms. In patients who failed desensitization, recurrence of symptoms occurred variably, either early (within days), within weeks, or delayed by more than 1 month.Lenalidomide desensitization is worthwhile and allows continuation of treatment. In our MM cohort, lenalidomide desensitization was successful in only 50% of cases, including some cases in whom ongoing symptoms were mitigated by cotreatment with antihistamine.