Secondary Myelodysplastic Syndrome/Acute Myeloblastic Leukemia During Lenalidomide-Based Regimens in Relapsed and/or Refractory Multiple Myeloma Patients: Single Center Experience

Abstract 1867

Secondary myelodysplastic syndrome and acute myelogenous leukemia (2° MDS/AML) are well-known complications that can occur after alkylating agent therapy for multiple myeloma (MM) or other cancers. However, until recently, the survival of MM pts was relatively short, a feature which may have contributed to a relatively low reported incidence of this complication in MM. The introduction of novel agents has improved survival rates of MM pts; lenalidomide (len) + dexamethasone–currently approved for MM after one prior therapy– is one of the main regimens that has contributed to this finding. Since alkylating agents, either given orally or as part of high-dose melphalan + ASCT, still remain an important component of MM therapy, more pts may survive to be at risk for 2° MDS/AML. Using the MM database at PMH, we retrospectively reviewed the charts of patients with relapsed/refractory (rel/ref) MM treated with len-based regimens (>1 cycle) to determine the incidence and characteristics of 2° MDS/AML that developed during this therapy. Between 06/2006 and 08/2012 we identified 230 patients having received len-based therapy: len + corticosteroids 222 patients, len alone 8 patients, cyclophosphamide + len + prednisone (CPR) 32 patients. 2° MDS/AML developed in 9 patients (3.9%) at a median of 89.6 months (range 30–188) from the time of diagnosis of MM and 22.4 (2–56.6) months from the time of initiation of len regimens. The median follow-up from start of len was 1.6 years, and from the start of diagnosis 7.5 years. The median duration of len treatment was 9.4 months. The MDS/AML cytogenetic changes were variable, but four patients had deletions of all or part of chromosome 5. None of the 2° MDS/AML had translocation t(4;14), as compared to 5.9% in (−) MDS/AML subgroup. The characteristics of patients at the time of starting len, in those who later developed (+) or did not develop (−) 2° MDS/AML during therapy, are shown in Table 1.

Cumulative incidence of 2° AML/MDS from time of diagnosis to time of 2° AML/MDS is 4.5% [95% CI 2.2–9.2%] at 15 years. Cumulative incidence of 2° AML/MDS from starting time of len to time of AML/MDS is 5% [95% CI 2.4–10.4%] at 5 years. The incidence of 2° MDS/AML among those who had prior oral alkylators (OA) and/or concomitant OA was 10.5% (2/19 patients), concomitant cyclophosphamide only 7.6% (1/13), prior OA only 1.9% (3/152), and 6.5% for those who did not receive prior/concomitant OA (3/46).

Grade 3–4 neutropenia occurred during len in 44% versus 58% in those with and without 2° MDS/AML, respectively. G-CSF was used in 56% of pts who developed MDS compared with 53% who did not.

We conclude: 1) The cumulative incidence of MDS/AML from starting len to time of 2° AML/MDS was 5% at 5 years; 2) patients who developed 2° MDS/AML while on len regimens were slightly older, had slight male predominance, higher beta-2-microglobulin, creatinine and platelet count, less often received prior ASCT, thalidomide, and bortezomib, but had longer exposure to len; 3) the relationship with OA is not entirely certain, but it appears that those with prior and concomitant exposure to OA have the highest incidence of this complication, which is most often seen in prolonged len treatment.