Azacitidine Is Feasible and Safe in Patients with MDS and Co-Existing Plasma Cell Dysplasias (PCD) - Report on 9 Patients From the Austrian Azacitidine Registry (AAR)

Abstract 5056

Azacitidine (AZA) has been approved for the treatment of higher-risk MDS and therefore marks a cornerstone in the development of hypomethylating agents. Recent clinical trials raise questions regarding optimal sequencing and also about combining hypomethylating agents with other classes of drugs targeting epigenetic processes. It has been postulated that unspecific demethylation of promotors may lead to the activation of oncogenes, and therefore result in an elevated rate of secondary malignancies.

We report on 9 patients from the Austrian Azacitidine Registry (AAR) with co-excisting plasma cell dyscrasias (PCD) receiving treatment with AZA for MDS. Six male and 3 female patients had a median age of 73 years at time of diagnosis of MDS and 73 years at time of diagnosis of PCD. They were diagnosed with Waldenstrom macroglobulinemia (WMG) (n=3), multiple myeloma (n=2) and MGUS (IgG (n=2), IgM (n=1), IgA (n=1)). All PCD were diagnosed either before or at least at the same time as MDS. None occurred after diagnosis of MDS or after treatment initiation with AZA. However, one patient with multiple myeloma likely had treatment–related MDS due to prior treatment with MPT (melphalan, prednisone, thalidomide).

At the time of writing, the mean number of AZA cycles given was 9 (range 1–27). Two patients were concomitantly treated with Rituximab (R) whilst on AZA treatment. Importantly, no additional toxicities occurred and there seemed to be no negative interaction between Rituximab and AZA. In all patients treated with AZA for MDS, M-gradient remained stable, and in some cases significant improvement was noted. One patient even achieved complete remission of WMG following AZA/R treatment (data will be shown; Weiss L et al, J Clin Oncol. 2011 Jul 25 [Epub ahead of print]). Importantly, no progression of PCD was seen in any of the 9 patients treated with AZA, and PCD did not contribute to death in any of these patients.

In conclusion, AZA treatment of MDS in patients with co-existing PCD seems safe, combination with Rituximab seems feasible, no aggravation of PCD was seen and remarkably, one patient with WMG achieved CR following AZA/R.