Considerations of when to proceed to an allogeneic HCT in a transplantation-eligible patient with higher-risk MDS in the context of an anticipated prior treatment with AZA according to the AZA prognostic score.21 The benefit of a therapy with single-agent AZA can be estimated according to the AZA prognostic score. As a result, one might estimate the optimal time point of when to consider proceeding to allogeneic HCT in a transplantation-eligible patient. Several trials with AZA have shown that at least 80% of patients achieved their best response after only 6 cycles of treatment. This means that only a minority of patients can further deepen their magnitude of response (eg, from partial to complete response) by the administration of additional cycles. Therefore, the continuation of AZA is considered to preserve the response already achieved at this time point. Patients with an AZA score of ≥ 1 have, in general, a high likelihood to lose their response early, even in the presence of a subsequent continuation of AZA. Therefore, I suggest limiting exposure to AZA in this group of patients in cases in which a donor has been already identified. OS indicates overall survival; PB, peripheral blood; and ECOG, Eastern Cooperative Oncology Group performance status.
