Characteristics and Outcomes Of Patients (pts) With Multiple Myeloma (MM) Who Develop Therapy (t)-Related Myelodysplastic Syndrome (MDS), t-Chronic Myelomonocytic Leukemia (CMML), Or t-Acute Myeloid Leukemia (AML)

There has been a significant improvement in the outcome for patients (pts) with MM over the last decade, mainly due to the availability of immunomodulatory (IMiD) drugs and proteasome inhibitors (PI). The improvement in survival has also increased the risk of second primary malignancies (SPM), such as therapy-related myelodysplastic syndrome (t-MDS), therapy-related chronic myelomonocytic leukemia (t-CMML) or therapy-related acute myeloid leukemia (t-AML). However, little is known about the characteristics and outcomes of pts with t-MDS, t-CMML or t-AML.

We aimed to study the characteristics and outcome of pts who developed t-MDS, t-AML and t-CMML as SPM after the treatment of MM. We reviewed our database of pts with MM who were treated at our institution between 1993 and 2011. We identified 49 pts who were diagnosed to have t-MDS, t-CMML, or t-AML. The primary objective of this study was to evaluate the time to develop t-MDS, t-AML and t-CMML, their response to treatment and overall survival.

Median age of pts at diagnosis of MM was 61 years. Forty-seven (96%) pts had symptomatic MM, while 2 (4%) had asymptomatic myeloma. Forty-seven (95%) pts with symptomatic myeloma received systemic therapy. Eleven (22%) pts were treated with IMiD or PI: lenalidomide 3, thalidomide 6 and bortezomib 2. Thirty-eight (78%) pts were treated with various conventional chemotherapeutic agents including melphalan, cyclophosphamide, doxorubicin, vincristine, etoposide, cisplatin, idarubicin, thiotepa, busulfan, carmustine and cytarabine. Fourteen (28%) pts also received radiation therapy to the affected areas. Twenty (41%) pts underwent high-dose chemotherapy and autologous hematopoietic stem cell transplantation (auto-HCT). Fourteen pts received maintenance therapy after auto-HCT with either thalidomide, lenalidomide, dexamethasone or bortezomib. Median time from the diagnosis of MM to t-MDS, t-CMML or t-AML was 6 years [0 – 24]. Thirty-four (69 %) pts developed t-MDS, 12 (24%) t-AML, and 3 (6%) t-CMML. Median age at diagnosis of t-MDS, t- CMML, or t-AML was 65 years. Twenty-seven (79%) pts with t-MDS and all 12 pts with t-AML had complex/high risk cytogenetics. Most common cytogenetic abnormalities involved chromosome 5 and 7. Thirty four (69%) pts received at least 1 cycle of induction chemotherapy either with conventional chemotherapeutic agents or investigational drugs. Only 9 pts (26%) achieved complete remission (CR). Median duration of CR in these pts was 4 months [1 – 62]. Median overall survival (OS) of pts who received induction therapy was 6.0 months [0-30]. Five (11%) pts received an allogeneic stem cell transplant with three achieving CR. Median OS in this subgroup of pts was 18 months [9 – 23]. Median OS for all 49 pts after diagnosis of t-MDS, t-CMML or t-AML was 6.0 months [0 – 30]

Development of t-MDS, t-CMML, or t-AML in pts with MM is associated with a poor outcome. These pts in general have complex cytogenetic abnormalities, chemo-resistant disease, a short CR and OS. A better understanding of disease biology and novel therapeutic approaches are warranted.

Orlowski:Bristol-Myers Squibb: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Millennium: The Takeda Oncology Company: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Onyx: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding; Resverlogix: Research Funding; Array Biopharma: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Genentech: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Merck: Membership on an entity’s Board of Directors or advisory committees. Qazilbash:Otsuka: Research Funding; Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Millennium Pharmaceuticals: Honoraria, Membership on an entity’s Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity’s Board of Directors or advisory committees.