Luspatercept Versus Placebo for Treating Subjects with Myelofibrosis on JAK2 Inhibitor Therapy and Who Require Red Blood Cell Transfusions

Clinical Trial Title

Study of Luspatercept (ACE-536) versus Placebo in Subjects with Myeloproliferative Neoplasm-Associated Myelofibrosis on Concomitant JAK2 Inhibitor Therapy and Who Require Red Blood Cell Transfusions (INDEPENDENCE)

National Clinical Trial Number:


Contact Information

Rush Cancer Center Clinical Trials Office

Clinical Trial Protocol Description:

Primary myelofibrosis is a condition characterized by the buildup of scar tissue (fibrosis) in the bone marrow, the tissue that produces blood cells. Because of the fibrosis, the bone marrow is unable to make enough normal blood cells. The shortage of blood cells causes many of the signs and symptoms of primary myelofibrosis.

Initially, most people with primary myelofibrosis have no signs or symptoms. Eventually, fibrosis can lead to a reduction in the number of red blood cells, white blood cells, and platelets. A shortage of red blood cells (anemia) often causes extreme tiredness (fatigue) or shortness of breath. A loss of white blood cells can lead to an increased number of infections, and a reduction of platelets can cause easy bleeding or bruising.

The main purpose of this study is to see if people with myeloproliferative neoplasm (MPN)-associated myelofibrosis who are also receiving treatment with a Janus Kinase 2 (JAK2) inhibitor and need blood transfusions will stop needing red blood cell (RBC) transfusions or require less frequent RBC transfusions by taking luspatercept. 

Luspatercept is a soluble, recombinant fusion protein that enhances red blood cell production and prevents anemia. It has not been approved for the treatment of anemia due to MPN-associated myelofibrosis, and its use in this study is investigational.

Participation in the study includes: A 28-day Screening Period where the study doctor will perform tests and review information from the potential subject’s medical history to find out whether they can participate in the study; A Treatment Phase that will be double-blinded (which means that neither the participating subject nor the study doctor will know which study treatment the participating subject is on, whether it is luspatercept or placebo). In addition to the study treatment, participating subjects will also receive best supportive care when appropriate. Best supportive care can include, but is not limited to, treatment with blood transfusions, anti-nausea medications, antibiotic therapies, or nutritional support.

A participating subject will have a 67% chance to receive luspatercept and a 33% chance to receive placebo. Participating subjects will be receiving the study treatment (luspatercept or placebo) administered as a subcutaneous (meaning beneath the skin, given in the upper arm, abdomen, or thigh) injection on Day 1 of every 21-day treatment cycle. For the placebo, it will be a subcutaneous injection of normal saline solution not containing luspatercept on Day 1 of every 21-day treatment cycle.

Clinical Trial Eligibility Criteria:

In order to participate you must meet the following criteria:

  • Are 18 years of age or older and have been diagnosed with primary myelofibrosis, post-polycythemia vera, or post-essential thrombocythemia myelofibrosis.
  • Average 4 to 12 RBC transfusion units/12 weeks. There must be no interval greater than 6 weeks (42 days) without 1 or more RBC transfusions.
  • Are on continuous JAK2 inhibitor therapy as part of your standard-of-care therapy for at least 32 weeks, on a stable daily dose.

You will be excluded from the study if any of the following criteria apply to you:

  • Have anemia from a cause other than MPN-associated MF or JAK2 inhibitor therapy, such as: iron deficiency, vitamin B12 and/or folate deficiencies, autoimmune or hemolytic anemia, infection, or any type of known clinically significant bleeding.
  • Have used hydroxyurea, immunomodulatory compounds such as pomalidomide, thalidomide, ESAs, androgenic steroids or other drugs with potential effects on blood production less than or equal to 8 weeks before joining the study.
  • Have uncontrolled hypertension or have prior history of malignancies, other than the disease under study, unless the you have been free of the disease for 3 or more years.

This is a partial list of eligibility requirements. To inquire about your eligibility, please call the contact number provided. If you wish to inquire via email, please include the title of the study in your message.

Study Details

Clinical Trial Investigator

Melissa Larson, MD

Contact Information

Rush Cancer Center Clinical Trials Office

Clinical Trial Location

Rush University Medical Center


Rush University Medical Center

1620 W Harrison St
Chicago, IL 60612

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