(PA-136) An Effective Lenalidomide Desensitization for Delayed Hypersensitivity-induced Rash in Patients with Multiple Myeloma

Lenalidomide is a standard of care in newly diagnosed multiple myeloma (MM). Some MM patients might develop delayed hypersensitivity to lenalidomide, which can lead to treatment discontinuation. Desensitization to lenalidomide can help these patients to complete treatment courses. Here, we aimed to review lenalidomide-treated MM patients who developed delayed hypersensitivity-induced rash were treated with desensitization.

Methods:   

We have developed and are using a desensitization protocol for patients who developed delayed hypersensitivity after using lenalidomide since 2022. A retrospective analysis of medical files of MM patients, who were desensitized by this protocol. Patients were treated between March 2022 and December 2024. A desensitization protocol was performed on patients with lenalidomide-induced delayed hypersensitivity accompanied by skin rash and itching of grade 2 or higher.

Desensitization was designed as a 21-day protocol to reach the dose of 25 mg. The starting dose was 0.1 mg in a dilution of 0.4/100 of the target 25 mg, escalating gradually. Once the target dose was tolerated, the modified tailored protocol was maintained in the following cycles.

Results:   

During the study period, a total of 114 patients were newly diagnosed with multiple myeloma. All of them received chemotherapy including lenalidomide as first-line treatment. Delayed hypersensitivity to lenalidomide like urticaria, eczematous rash, or maculopapular erupotions occurred in 33 patients who received lenalidomide-based chemotherapy as first-line treatment. Among the 33 patients, lenalidomide desensitization was performed on 14 patients with severe symptoms. The median age of these patients was 65 years (range, 52-82 years). Of these, 8 received RVD regimen and 6 received Rd regimen. The median dose of lenalidomide administered to them was 22 mg/day, and the median time to onset was 14 days (range, 7-35 days).

Of the 14 patients, 12 (85.7%) succeeded in completing the protocol and thus were able to continue lenalidomide treatment cycles. The 12 patients tolerated their target dose. Because itching was a common adverse effect of lenalidomide, antihistamines were used to control itching for all enrolled patients, and for patients with skin eruption of grade 2 or 3, low-dose steroids were used concurrently. None of the patients that were treated with desensitization had severe immune-mediated or non-dermatologic adverse reactions. Of the two patients in whom lenalidomide desensitization failed, one developed grade IV skin eruption and received high-dose steroid therapy, and the other patients continued to have itching, leading to discontinuation of lenalidomide in both patients.

Conclusions:   

Desensitization to lenalidomide is safe and effective. Desensitization of lenalidomide-induced delayed hypersensitivity can reduce lenalidomide discontinuation and allow for more effective treatment of multiple myeloma.