Decrease in JAK2 V617F allele burden is not a prerequisite to clinical response in patients with polycythemia vera.

Abstract

BACKGROUND:

Although reduction in the JAK2(V617F) allele burden (%V617F) has been suggested as a criterion for defining disease response to cytoreductive therapy in polycythemia vera, its value as a response monitor is unclear. The purpose of this study is to determine whether a reduction in %V617F in polycythemia vera is a prerequisite to achieving hematologic remission in response to cytoreductive therapy.

DESIGN AND METHODS:

We compared the clinical and hematologic responses to change in %V617F (molecular response) in 73 patients with polycythemia vera treated with either interferon (rIFNα-2b: 28, Peg-rIFNα-2a: 18) or non-interferon drugs (n=27), which included hydroxyurea (n=8), imatinib (n=12), dasatinib (n=5), busulfan (n=1), and radioactive phosphorus (n=1). Hematologic response evaluation employed Polycythemia Vera Study Group criteria, and molecular response evaluation, European Leukemia Net criteria.

RESULTS:

Of the 46 treated with interferon, 41 (89.1%) had a hematologic response, whereas only 7 (15.2%) had a partial molecular response. Of the 27 who received non-interferon treatments, 16 (59.3%) had a hematologic response, but only 2 (7.4%) had a molecular response. Median duration of follow up was 2.8 years. Statistical agreement between hematologic response and molecular response was poor in all treatment groups.

CONCLUSIONS:

Generally, hematologic response was not accompanied by molecular response. Therefore, a quantitative change in %V617F is not required for clinical response in patients with polycythemia vera.

• Authors: Emil Kuriakose, Katherine Vandris, Y Lynn Wang, William Chow, Amy V Jones, Paul Christos, Nicholas C P Cross, Richard T Silver
• Journal: Haematologica (Haematologica) Vol. 97 Issue 4 Pg. 538-42 (Apr 2012) ISSN: 1592-8721 [Electronic] Italy
• PMID: 22102708 (Publication Type: Journal Article, Research Support, N.I.H., Extramural, Research Support, Non-U.S. Gov't)

Chemical References

• Interferon-alpha
• Janus Kinase 2

Topics

• Adult
• Aged
• Alleles
• Follow-Up Studies
• Humans
• Interferon-alpha (therapeutic use)
• Janus Kinase 2 (genetics)
• Middle Aged
• Mutation
• Polycythemia Vera (drug therapy, genetics)
• Remission Induction
• Treatment Outcome