Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

Cancer Health Center

Font Size

Chronic Myeloproliferative Neoplasms Treatment (PDQ®): Treatment - Health Professional Information [NCI] - Primary Myelofibrosis


Ruxolitinib, an inhibitor of JAK1 and JAK2, can reduce the splenomegaly and debilitating symptoms of weight loss, fatigue, and night sweats for patients with JAK2-positive or JAK2-negative primary myelofibrosis, post-essential thrombocythemia myelofibrosis, or post-p. vera myelofibrosis.[29]

In two prospective, randomized trials, 528 higher-risk patients were randomly assigned to ruxolitinib or to either placebo (COMFORT-I [NCT00952289]) or best available therapy (COMFORT-II [NCT00934544]). At 48 weeks, patients on ruxolitinib had a decrease of 30% to 40% in mean spleen volume compared with an increase of 7% to 8% in the control patients.[30][Level of evidence: 1iiDiv]; [31][Level of evidence: 1iDiv] Ruxolitinib also improved overall quality-of-life measures, with low toxic effects in both studies, but with no benefit in overall survival in the initial reports. Additional follow-up in both studies (1 year in COMFORT-I and 2 years in COMFORT-II) showed a survival benefit among ruxolitinib-treated patients compared with control patients (COMFORT-I hazard ratio [HR], 0.58; 95% confidence interval [CI], 0.36-0.95; and COMFORT-II HR, 0.48; 95% CI, 0.28-0.85).[32,33][Level of evidence: 1iiA] Clinical benefits were observed across a wide variety of clinical subgroups.[34,35] Discontinuation of ruxolitinib results in a rapid worsening of splenomegaly and the recurrence of systemic symptoms.[30,31,36] Ruxolitinib does not reverse bone marrow fibrosis or induce histologic or cytogenetic remissions. More selective JAK inhibitors are currently being evaluated in clinical trials.[37,38]

Painful splenomegaly can be treated temporarily with ruxolitinib, hydroxyurea, thalidomide, lenalidomide, cladribine, or radiation therapy, but sometimes requires splenectomy.[21,39,40] The decision to perform splenectomy represents a weighing of the benefits (i.e., reduction of symptoms, decreased portal hypertension, and less need for red blood cell transfusions lasting for 1 to 2 years) versus the debits (i.e., postoperative mortality of 10% and morbidity of 30% caused by infection, bleeding, or thrombosis; no benefit for thrombocytopenia; and accelerated progression to the blast-crisis phase that was seen by some investigators but not others).[4,39]

After splenectomy, many physicians use anticoagulation therapy for 4 to 6 weeks to reduce portal vein thrombosis, and hydroxyurea can be utilized to reduce high platelet levels (>1 million).[41] However, data from a retrospective review of 150 patients who underwent surgery provided documentation that 8% of the patients had a thromboembolism and 7% had a major hemorrhage with prior cytoreduction and postoperative subcutaneous heparin used in one-half of the patients.[42]

Next Article:

Today on WebMD

Colorectal cancer cells
New! I AM Not Cancer Facebook Group
Lung cancer xray
See it in pictures, plus read the facts.
sauteed cherry tomatoes
Fight cancer one plate at a time.
Ovarian cancer illustration
Real Cancer Perspectives
Jennifer Goodman Linn self-portrait
what is your cancer risk
colorectal cancer treatment advances
breast cancer overview slideshow
prostate cancer overview
lung cancer overview slideshow
ovarian cancer overview slideshow
Actor Michael Douglas