Risk of Second Primary Malignancies in Patients with AL Amyloidosis Treated with Lenalidomide

Abstract 1873

An increase in second primary malignancies (SPM) has been reported in patients with myeloma treated with lenalidomide, particularly in association with melphalan. To determine the rate of second primary malignancies in AL amyloidosis patients treated with lenalidomide, we reviewed data on 82 patients treated on clinical trials at Boston Medical Center from 2004–2011. Data from lenalidomide and dexamethasone treatment in AL amyloidosis (ClinicalTrials.gov: NCT00091260) were analyzed in a post-hoc fashion for the incidence rate for SPM. The median age of these 82 patients was 62 years (range, 40–82); and 52 (63%) were male. There were 62 patients (76%) with lambda clonal plasma cell dyscrasia, and 43 (52%) had cardiac involvement by the consensus criteria from the X^th International Amyloidosis Symposium. Median duration for lenalidomide treatment was 9 cycles (range, 1–69); and 16 (20%) received lenalidomide for > 24 months. Of the 82 patients, 78 (95%) patients had prior therapies and 77 (94%) had prior alkylating agents based treatment. The median follow-up of the 82 patients was 28 months (range, 3–92). One patient, a smoker, treated with lenalidomide for 24 months, developed metastatic lung cancer. Additionally, there were 5 non-melanoma skin cancers. There was no case of hematologic malignancy or B-cell lymphoproliferative disorder in this group. This corresponds to an incidence rate of 0.44 per 100 patient-years for invasive cancer. The annual incidence of invasive cancers is 2.1 per 100 patient-years for the general population in the US. In conclusion, lenalidomide based treatment in AL amyloidosis did not appear to increase the incidence rate of SPM compared to incidence rate for the invasive cancers in general population. Longer prospective follow-up may be needed in a larger patient population to better define the risk.