Randomized Switch Study From Hydroxyurea to Ruxolitinib for RELIEF of Polycythemia Vera Symptoms: The Relief Study

This is a Phase 3 multicenter, double-blind, double-dummy, randomized study. Only subjects
with PV who have received HU for at least 12 weeks, have been receiving a stable dose before
screening, and still have symptoms related to PV will be enrolled.

Subjects will be randomized (1:1) to 1 of 2 treatment arms:

A: ruxolitinib and HU-placebo B: HU and ruxolitinib-placebo

Subjects randomized to either arm may be eligible to transition to open-label ruxolitinib
after Week 16.

Inclusion Criteria:

- Subjects must currently be reporting symptoms while on a stable dose of HU monotherapy
and be eligible to continue HU on study after randomization.

- Before screening, the subject must have been receiving HU for at least 12 weeks AND be
receiving a stable dose.

- Subjects must meet baseline symptom criteria

- Subjects should meet at least 1 of the following criteria:

- No more than 2 phlebotomies within the 6 months before screening OR

- No palpable splenomegaly.

- Subjects must have a hematocrit that can be controlled within 35% to 48% (inclusive)
before randomization.

Exclusion Criteria:

- Subjects with inadequate liver or renal function at screening.

- Subjects with clinically significant infection that requires therapy

- Subjects with known active hepatitis A, B, or C at screening or with known HIV
positivity.

- Subjects with an active malignancy over the previous 2 years

- Subjects with clinically significant cardiac disease (Class III or IV).