The CALGB conducted a series of clinical trials with azacitidine (Vidaza®) administered subcutaneously or intravenously in patients with MDS using the FAB classification (

JCO 2002;20:2429
). Since the publication of these CALGB studies (8421, 8921, 9221), new response criteria for evaluating new treatments for MDS have been published by the IWG (
Blood 2000;96:3671
). Two general differences between the CALGB and IWG response criteria are the required duration of improvement (CALGB: ≥4 weeks; IWG: ≥8 weeks) and peripheral blood values (CALGB: different criteria for hemoglobin targets for males and females; IWG: same criteria for males and females). The results reported here are based on re-collected data from patients described in the published report. After applying the IWG response criteria, the overall response rate (CR+PR+HI) in the azacitidine groups were similar across studies 8421, 8921, and 9221: 44% (21/48), 40% (28/70), and 48% (47/99), respectively.

Best Response using IWG Response Criteria for MDS in Studies 8421, 8921, and 9221

Best Response using IWG Response Criteria for MDS in Studies 8421, 8921, and 9221
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Best Response using IWG Response Criteria for MDS in Studies 8421, 8921, and 9221
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Median duration of any response (CR, PR or HI) in the 114 azacitidine-treated responders was 366 days (range: 56 to 4641+ days). The median duration of CR in the 32 azacitidine-treated responders was 379 days (range: 92 to 4412+ days). The median number of cycles from first treatment with azacitidine to any response (CR, PR or HI) was 3 cycles (range: 1 to 17 cycles). Although 75% of the responders achieved a response by cycle 4, the other 25% achieved a response as late as cycle 17. The majority (90%) of responders achieved a response by cycle 6. Best response was observed, on average, 2 cycles after the initial response. In summary, reanalysis of the response rates using IWG criteria demonstrate consistent results across three sequential studies and further validate the superiority of azacitidine over supportive care alone.

Topics:
azacitidine, frequency of responses, myelodysplastic syndrome, hemoglobin, supportive care, cancer and leukemia group b

Author notes

Corresponding author

2005, The American Society of Hematology
2005
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