Therapy With Demethylating Agents Significantly Improves Overall- and AML-Free Survival In Patients With MDS Classified As High-Risk By IPSS Or Very High Risk By IPSS-R and Partial Or Total Monosomy 7-Results From a German Multicenter Study

Introduction Total (-7) or partial (7q-) monosomy 7 is frequent in malignant myeloid disorders, observed in around 12% of MDS/AML and up to 40% of therapy-associated MDS/AML. Monosomy 7 is associated with poor outcome, high susceptibility to infections and poor response to chemotherapy. A therapeutic benefit for 5-azacytidine was previously described (Fenaux et al., 2009). The present study was designed to analyze clinical features, prognosis and response to different therapeutic strategies in patients with monosomy 7 in a multicentric, retrospective German cohort study. Patients and methods Currently, 231 patients with MDS/AML following MDS and monosomy 7 were included. Inclusion criteria were defined as follows: Morphologic diagnosis of MDS/AML following MDS, age ≥18 years, bone marrow blast count ≤30% and presence of -7 or 7q-. The data was assembled from centers in Dusseldorf, (n=120; 52%), Cologne (n=38; 17%), Freiburg (n=31; 13%), Gottingen (n=14; 6%), Munich (n=13; 6%), Dresden (n=11; 5%) and Mannheim (n=4; 2%). The median age in the study cohort was 67 years, 65% of patients were males. 29/231 patients (13%) were diagnosed as AML following MDS. MDS/AML was therapy-associated in 24 patients (11%). Regarding IPSS, 38 (19%) were classified as low/intermediate 1 risk and 165 (81%) as intermediate-2/high-risk. According to IPSS-R, 2 (1%) were assigned to the very-low/low risk group, 31 (16%) to the intermediate group, 52 (27%) to the high-risk group and 107 (56%) to the very high risk group. The treatment was classified as follows: Best supportive care (BSC), low-dose Chemotherapy (LDC), high-dose chemotherapy (HDC), demethylating agents (DMA; either 5-azacytidine or decitabine), and others. Results A best supportive care regimen was chosen in nearly half of the patients (49%). The remaining patients received 1-4 sequential therapies (1: 29%; 2: 11%; 3: 10%; 4: 1%). As the first line therapy, 64 patients (54%) received DMA, 24 (20%) an allo-Tx, 9 (8%) HDC, 5 (4%) LDC, and 16 (14%) were treated with other therapies. The best prognosis was observed in patients eligible for allo-Tx: The median OS in transplanted patients was 924 days as compared to 361 days (p<0.01) in patients not eligible for transplantation. In the latter cohort, patients who received DMA at any course of their disease did not differ from those receiving other therapies: The median OS was 468 days in patients treated with DMA as compared to 325 on those with alternative therapies (p not significant) and the median time to AML-transformation was 580 versus 818 days (p not significant), respectively. However, by classifying patients according to IPSS- and IPSS-R, it became obvious that patients with an IPSS high-risk or an IPSS-R very high risk showed a clear benefit from DMA: In the first group, median OS was 444 days in DMA-treated and 201 days in non-DMA-treated patients (p=0.048), in the latter group, median OS 444 days in the DMA-treated and 203 days in the non-DMA treated cohort (p=0.017). Comparable results were observed regarding AML-free survival: Median time to AML was 580 (DMA) vs. 186 (no DMA) days in IPSS high risk patients (p=0.031) and 580 (DMA) vs. 273 (no DMA) days in the IPSS-R very high risk group (p not significant). Conclusions Patients with MDS, partial or total monosomy 7 and a high risk according to IPSS or a very high risk according to IPSS-R show a pronounced benefit when treated with DMA, regarding overall- as well as AML-free survival. Further results from the ongoing data analysis will be presented in detail. The study was supported by research funding from Celgene. Disclosures: Schanz: Celgene: Research Funding. Braulke: Celgene: Research Funding. Germing: Celgene: Honoraria, Research Funding. Schmitz: Novartis: Research Funding; Celegene: Consultancy, Research Funding, Speakers Bureau. Gotze: Celgene: Honoraria. Platzbecker: Celgene: Honoraria, Research Funding. Haase: Celgene: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding.