Busulphan efficacy and safety based on real-world dosing patterns in MPN management

Treatments for patients with MPNs primarily aim to reduce thrombotic risks by managing blood counts using cytoreductive agents. The alkylating agent busulphan has been used historically to manage MPNs, providing an orally administered and cost-effective myelosuppressive option. However, its use has been limited due to concerns about leukemic transformation. Current prescribing practices vary considerably, with a lack of consensus.

Mahdi et al. conducted a real-world, retrospective study across 13 UK treatment centers evaluating prescribing regimens, characteristics, and outcomes of MPN patients treated with busulphan. A total of 115 patients diagnosed with ET (67%), PV (24%), MF (4%), and other MPN (5%) were included, with a median age of 78 years. ORR was defined as patients achieving a CR or PR as per ELN criteria. Findings were published in the European Journal of Haematology.¹

Key learnings¹

Busulphan rapidly reduced blood counts, with an ORR of 78.1%. The time to maximum response was 3 months for patients with PV and 4 months for those with ET, with 29% of PV and 18% of ET patients achieving CRs.

Busulphan dosing regimens were distributed comparably between repeated single doses (31%), 1–4 week treatment courses (30%), and continuous therapy for >4 weeks (35%), with no significant differences in outcomes observed between dosing patterns.

During the median follow-up of 23 months, no cases of disease progression to MF or acute leukemia were reported. Busulphan-related complications were reported in 14% of patients, with cytopenia and fatigue being the most common (4% each). 

These findings suggest that busulphan is a viable cytoreductive option with a favorable safety profile and should be considered in patients with a life expectancy of <10 years; particularly for elderly patients who are intolerant to standard cytoreductive therapies.