For a subset of patients with PV,
Conventional approaches to disease management may result in inadequately controlled PV
Key measures of inadequately controlled PV
Any of the following may suggest inadequately controlled PV:
Consensus guidelines help define HU resistance and intolerance
- Guidelines published by the ELN can be used to help identify patients who have developed HU resistance and intolerance3
- The RESPONSE trial, which assessed JAKAVI in PV, used a modified version of these guidelines to determine eligibility—these patients had inadequate response to or unacceptable side effects from HU4
Criteria for HU resistance5

Published ELN guidelines define resistance after 3 months of treatment only at a dose of ≥2 g/day of HU.3
*Or failure to completely relieve symptoms related to splenomegaly. Massive splenomegaly was defined as spleen extending >10 cm below the costal margin.5
Criteria for HU intolerance5

†Or clinicohaematologic response. Complete response is defined as haematocrit <45% without phlebotomy, platelet count ≤400 × 109/L, WBC count ≤10 × 109/L, and no disease-related symptoms. Partial response is defined as haematocrit <45% without phlebotomy or response in three or more of the other criteria.
Some patients who do not meet ELN criteria for HU resistance/intolerance may still have an inadequate response or intolerance to HU or remain symptomatic6,7