A NEW prognostic model may help clinicians identify patients with polycythaemia vera (PV) who are at greater risk of disease complications after treatment with ruxolitinib.
Researchers found that assessing treatment response during the first 6 months of ruxolitinib therapy could separate patients into markedly different long-term risk groups, potentially providing an early opportunity to optimise treatment.
RUXOLITINIB is widely used to treat patients with PV, a slow-growing blood cancer where the bone marrow makes too many red blood cells, following failure or intolerance of hydroxyurea. However, there is currently a lack of validated response criteria capable of predicting long-term outcomes in patients receiving the drug.
To address this, researchers analysed 178 patients with PV enrolled in the observational PV-ARC study and examined clinical characteristics at the start of ruxolitinib treatment and then again after 3 and 6 months.
The primary outcome for the study was event-free survival, with events including progression to post-PV myelofibrosis, thrombosis, haemorrhage, or death.
After a median follow-up of 3.5 years, 15 patients had died, seven experienced thrombosis, nine experienced haemorrhage, and 21 progressed to myelofibrosis. Overall, 5-year event-free survival was 70.4%.
Researchers found that three factors independently predicted poorer outcomes: receiving a ruxolitinib dose below 10 mg twice daily at one or more assessed time points, failure to achieve at least a 50% reduction in spleen length at months 3 and 6, and requiring phlebotomy at two or more assessed time points.
Using these factors, the researchers developed the PV-Response to Ruxolitinib after 6 Months (PV-RR6) prognostic model.
The model separated patients into low, intermediate, and high-risk groups, revealing substantial differences in long-term outcomes.
Patients classified as low risk had an 89.4% 5-year event-free survival rate, while the rate was 71.0% among intermediate-risk patients. In comparison, patients classified as high risk had a 5-year event-free survival rate of just 38.9%.
The difference between the three groups was statistically significant.
Failure to achieve a substantial reduction in spleen size was the factor that showed the strongest individual association with poorer event-free survival, while persistent phlebotomy requirements and lower ruxolitinib doses were also independently associated with increased risk.
The findings suggest that clinicians may be able to use a patient’s first 6 months of ruxolitinib treatment to gain an early indication of their longer-term prognosis.
Unlike prognostic approaches based primarily on characteristics measured before treatment, PV-RR6 incorporates how the disease responds during therapy, including spleen reduction and haematocrit control.
This could help identify patients whose disease appears inadequately controlled despite ruxolitinib and who may benefit from earlier treatment optimisation rather than waiting for disease progression or another major clinical event.
However, the study was observational, meaning the associations identified cannot establish that changing treatment based on the score will improve outcomes. Further validation of PV-RR6 in independent patient populations will also be needed before it can be incorporated into routine clinical decision making.
Nevertheless, the researchers suggest the model could provide a practical tool for identifying higher-risk patients relatively early in their treatment course and supporting more timely management decisions.
Reference
Palandri F et al. A dynamic prognostic model for Polycythemia Vera long-term outcomes in patients treated with Ruxolitinib. Blood Advances. 2026. doi:10.1182/bloodadvances.2026020255.
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