Sponsor: University of Copenhagen, Department of Haematology, Herlev Hospital

Principal investigators: Hans Carl Hasselbalch, Mary Frances McMullin

Primary objectives:
- To evaluate efficacy of vorinostat in the treatment of patients with polycythaemia vera (PV) and essential thrombocythaemia (ET)
- To evaluate if vorinostat as monotherapy of patients with PV and ET is followed by a decline in clonal myeloproliferation as assessed by conventional disease activity parameters ( a decrease in the need of phlebotomy ( PV) , leukocyte and platelet counts)
- To investigate whether treatment with vorinostat influences the JAK2 mutation status as assessed by quantitative PCR

Status: Inclusion and follow-up completed. Results presented at EHA 2011. Final publication was submitted July 2012.

Start: 2009

Research support: MSD

Study design: Non-randomized, open-label pilot study (phase II) of 60 patients. The inclusion period is about 2 year.

Inclusion criteria:
- Male or female patient > 18 years of age and
- A confirmed diagnosis of PV or high-risk ET and
- Biochemical evidence of active disease

Exclusion criteria:
- A platelet count > 1500 x 109/L (a need for cytoreduction in platelet count)
- Patients of childbearing potential without a negative pregnancy test prior to initiation of study drug.
- Women who are breast feeding
- Males and females not using contraceptives if sexually active
- ECOG Performance Status Score >/= 3.
- Serum creatinine more than 2 x‚s the ULN
- Total serum bilirubin more than 1.5 x‚s the ULN
- Serum AST/ALT more than 3 x‚s the ULN
- Interferon alpha within 1 week of day 1
- Hydroxycarbamide within 1 week of day 1
- Anagrelide within 1 week of day 1
- Valproic acid (as an anticonvulsant) within 28 days of day 1
- Any other investigational drug within 28 days of day 1
- Active HIV, HBV or HCV infection.
- Any serious concomitant disease or circumstances that could limit compliance with the study, including but not limited to the following: CTCAE grade 3-4 cardiac general & arrhythmia, or psychiatric or social conditions that may interfere with patient compliance.

Treatment: Caps. Vorinostat a 100 mg , 400 mg/day for 6 months. Responding patients will be offered prolonged therapy.

Contact person: In Denmark Hans Carl Hasselbalch, in Sweden Elisabeth Ejerblad