Clinical Outcomes of 420 MDS Patients Treated with 5-Azacytidine: Evaluation of Overall Survival, Duration of Treatment and Rate of Discontinuation in a Real Life Study from the Italian MDS Registry of Fondazione Italiana Sindromi Mielodisplastiche (FISM)

Introduction

Azacytidine(AZA) is the current standard of care for patients with high-risk myelodysplastic syndrome (MDS) in Europe. AZA has shown a survival advantage when compared with conventional therapies and has also shown activity in IPSS lower-risk patients. However, about 40% of patients do not respond and most patients show a loss of response within 2 years. Treatment options for MDS patients who progressed while on, failed to respond to, or became intolerant tohypomethylatingagents are scarce and it has been shown that overall survival (OS) is extremely short. Objectives of this study were to describe in a cohort of real life MDS patients treated with AZA, the reasons to discontinue treatment, and to evaluate their clinical outcomes.

Methods

We present here the results of a real life study from a large group ofnon selectedpatients recorded in the MDS registry of FondazioneItalianaSindromiMielodisplastiche(FISM). Only patients treated with AZA from January 2009 to June 2014 were considered for the analysis. All types of conventional published schedules of AZA were allowed. The primary end point was the evaluation of OS from start of AZA treatment to the date of death from any cause. Secondary end points were clinical response, cause of discontinuation, salvage treatments and OS from discontinuation of the drug.

Results

Between January 2009 to June 2014 1799 newly diagnosed MDS patients were enrolled , and 420 received AZA; 271 patients received AZA as 1st line treatment, 115 patients as 2nd line treatment, 34 as a line ≥3rd. Median age was 73 years (IQR: 67-77); 261 patients (62%) were male. WHO diagnosis was RA or RARS (n=27, 6%), RCMD with or without RS (n=62, 15%) AREB-1 (n=126, 30%), AREB 2 (n=190, 45%), other subtypes (n=15, 4%). At start of AZA therapy IPSS score was low in 11 (3%), int-1 in 80 (19%), int-2 in 143 (34%), high in 54 patients (13%), and not available in 132 patients (31%). Forty-three (47%) low and int-1 risk MDS patients had a transfusion-dependent anemia. Patients received a median of 7 courses of treatment (range 3-12). Twenty-four patients (6%) received concomitant erythropoietin therapy. OS at 1 year from beginning of AZA therapy was 73% for the whole cohort (420 pts)(95%CI: 0.69-0.78), and median OS was 23 months, 25 months for patients with IPSS lower-risk MDS and 21 months for those with IPSS higher risk MDS (log-rank test: 0.72). OS after discontinuation of AZA was 8 months. Clinical response was reported according to IWG criteria only in 288/420 patients (69%); 94 patients (33%) achieved a hematological response, that was complete in 35 patients (12%) and partial in 59 (20%), 78 patients (27%) had stable disease while 116 (40%) patients did not respond. Response was achieved after a median of 6 cycles (IQR: 4-11), in both lower and higher risk MDS patients. After a median follow up of 16 months (IQR:7-35) in 97 patients (23%) AZA therapy was still ongoing and in 323 has been discontinued (77%). Interruption of treatment was due to loss of response/worsening of hematological parameters in 24 patients who achieved complete or partial response (7%) and in 20 patients with stable disease (6%). AML evolution was the cause for interruption in 105 cases (32%), death in 28 (9%), toxicity or poor compliance in only 26 (8%), while clinical decision of the treating hematologist determined interruption in 22 cases (7%). In additional 98 patients AZA was discontinued early for reasons not reported by the treating physician (30%). Of the 323 patients who discontinued AZA 10 (3%) were managed with intensive AML-like chemotherapy, 17 (5%) underwent an allogeneic HSCT, 18 (6%) received low-dose chemotherapy, 42 (14%) other treatments and 236 patients (73%) received only transfusions and other supportive therapy.

Conclusions

Our data confirm that AZA therapy is effective for MDS patients, both with higher and lower IPSS risk disease. Response rate is consistent with what previously reported and median OS is 23 months. The interesting observation is that at 16 months, 77% of patients had discontinued treatment, either for progression or loss of response (45% of cases) and only in 8% of cases for reported toxicity. As there are few treatment options after AZA interruption, it is important to establish the reasons other than progression yielding to a stop in therapy, in order to avoid too early discontinuation and loss of survival advantage.