Patients with myeloproliferative neoplasms in accelerated or blast phase (MPN-AP/BP) who revert to chronic phase (cMPN) after blast-reduction therapy, as well as those with complete response (CR) or CR with incomplete hematologic recovery (CRi) after blast reduction, experience improved overall survival (OS) outcomes after hematopoietic stem cell transplant (HSCT) consolidation therapy, according to findings from a single-center, retrospective analysis evaluating outcomes with intensive and nonintensive blast-reduction strategies in patients with MPN-AP/BP, which were published in Blood Advances.1
This study, which used clinically relatable response criteria developed at the Princess Margaret Cancer Centre, as well as the European LeukemiaNet (ELN) 2022 acute myeloid leukemia (AML) response criteria, found that patients who received intensive blast-reduction therapy achieved a best overall response rate (ORR) of 77% (n = 62/81) vs 39% (n = 21/54) in those who received nonintensive therapy. CR/CRi and cMPN reversions were observed in 24 and 38 patients in the intensive group and 4 and 17 patients in the nonintensive group, respectively.
Although allogeneic HSCT is the only therapy associated with long-term survival improvements for patients with MPN-AP/BP, this treatment strategy is typically reserved for patients who have achieved disease control. Other blast-reduction strategies include induction chemotherapy, as well as hypomethylating agents (HMAs)—such as azacitidine (Vidaza)—as monotherapy or in combination with agents such as venetoclax (Venclexta).2
“However, the optimal blast-reduction strategy and depth of disease clearance required before HSCT are unknown,” lead study author Marta B. Davidson, MD, PhD, FRCPC, of the Princess Margaret Cancer Centre in Toronto, Ontario, Canada, and coauthors, wrote in the paper.1 “Moreover, a lack of standardized response criteria to evaluate the treatment of MPN-AP/BP poses challenges for understanding treatment efficacy between reported studies.”