Intensive chemotherapy improved survival in patients with accelerated and blast phase myeloproliferative neoplasms, with Venclexta showing no clear benefit.
Venclexta (venetoclax)-based treatments did not improve how long patients with accelerated and blast phase myeloproliferative neoplasms (MPNs) lived without their disease getting worse, according to study findings presented at the European Hematology Association 2025 Congress.
In this UK study, intensive chemotherapy — which many older or less fit patients could not receive — led to the best overall and progression-free survival outcomes, especially for patients in blast phase, where stem cell transplant remains the main curative option. Researchers said more clinical trials are needed to guide treatment planning.
The overall response rate across all therapies was 46.2%. Median overall survival for the entire group was 13.4 months, with patients in blast phase living a median of 6.44 months compared to 21.9 months for those in accelerated phase.
Overall response rate: the proportion of patients whose tumors shrink or disappear, including both partial and complete responses.
Overall survival: time from treatment initiation until death from any cause.
Progression-free survival: time during and after treatment in which the disease does not worsen.
Intensive chemotherapy, given to 30 patients, was linked to the longest survival at 33.7 months, which was better than the 9.7 months seen with Vidaza (azacitidine) alone (19 patients) and the 14.9 months with Venclexta-based treatments (18 patients). Jakafi (ruxolitinib) showed a survival of 25.3 months, though this benefit came mainly from its use in combination with Vidaza in accelerated phase patients (17 patients). Patients who received no treatment had the shortest survival at 2.2 months.
Progression-free survival (PFS) for the entire group was 9.7 months. Intensive chemotherapy led to the longest PFS at 27.2 months, compared with 8.4 months for Vidaza alone and 9.1 months for Venclexta-based therapy. Jakafi combined with Vidaza tended to improve PFS compared with Jakafi alone, but only in accelerated phase patients (29.2 months versus 18 months).
A stem cell transplant was performed in 31 patients, more often in blast phase (24.2%) than accelerated phase (14%). Intensive chemotherapy patients were more likely to go on to transplant (73.3%) compared with Vidaza recipients (5.3%). Median survival after transplant was 23.5 months, with no significant difference between the two disease phases.
Between 2014 and 2024, researchers in the UK reviewed records from 152 people with MPNs that had progressed to either accelerated phase or blast phase. Of these, 57 had accelerated phase disease and 96 had blast phase disease. Patients were about 71 years old on average, ranging from 17 to 88 years.
The most common gene mutation was JAK2 (63.6%), followed by CALR (20%). On average, it took about 8.5 years from the original MPN diagnosis for the disease to develop into accelerated or blast phase, though for some it happened immediately and for others it took more than 22 years. Nearly all patients (92.9%) had received at least one treatment for their disease before it became accelerated or blast phase, with a median of one prior therapy and up to five in some cases.
Patients were grouped by whether they received active treatment or no active treatment for accelerated or blast phase disease, and whether they underwent a stem cell transplant from a donor. Researchers then compared overall survival and progression-free survival between groups using established statistical methods.
Accelerated and blast phase MPNs are aggressive blood cancers with a poor outlook. Doctors face challenges in treating these stages because there is no standard approach, few head-to-head studies comparing treatments and limited large, forward-looking clinical trials.
A stem cell transplant from a donor is the only potential cure, but many patients cannot have it because of age, health, or other medical conditions.
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