A Pilot Study of a Thrombopoietin-Receptor Agonist, Eltrombopag, in Patients With Low to Int-2 Risk Myelodysplastic Syndrome (MDS)

Background:

* Myelodysplastic syndromes (MDS) are bone marrow disorders characterized by anemia, neutropenia, and thrombocytopenia (low red blood cell, white blood cell, and platelet counts). Patients with MDS are at risk for symptomatic anemia, infection, and bleeding, as well as a risk of progression to acute leukemia. Standard treatments for MDS have significant relapse rates. MDS patients with thrombocytopenia who fail standard therapies require regular, expensive, and inconvenient platelet transfusions, and are at risk for further serious bleeding complications.
* Eltrombopag is a drug designed to mimic the protein thrombopoietin, which causes the body to make more platelets. Eltrombopag has been able to increase platelet counts in healthy volunteers and in patients with chronic ITP (a disease where patients destroy their own platelets very rapidly and thus develop thrombocytopenia), but researchers do not know if the drug can increase platelet counts in patients with MDS.

Objectives:

* To find out whether eltrombopag can improve platelet counts in patients with MDS.
* To determine whether eltrombopag is safe for patients with MDS.

Eligibility:

* Patients 18 years of age and older who have consistently low blood platelet counts related to MDS that has not responded to conventional treatment.
* Platelet count ≤ 30,000/μL or platelet-transfusion-dependence (requiring at least 4 platelet transfusions in the 8 weeks prior to study entry); OR hemoglobin less than 9.0 gr/dL or red cell transfusion-dependence (requiring at least 4 units of PRBCs in the eight weeks prior to study entry) OR ANC≤500

Design:

* Treatment with eltrombopag tablets once per day for 16-20 weeks.
* Participants will be monitored closely throughout the initial treatment, with weekly blood tests and separate evaluations at the National Institutes of Health (NIH) treatment center every 4 weeks. Bone marrow biopsies may be conducted to check for abnormalities in bone marrow.
* If patients show signs of improved platelet counts after 90 days, treatment will continue with additional doses of eltrombopag.
* Patients who discontinue taking eltrombopag will be evaluated at the NIH treatment center 4 weeks after ending treatment, and again 6 months after ending treatment to check for potential side effects.

The myelodysplastic syndromes (MDS) are bone marrow disorders characterized by anemia, neutropenia, and thrombocytopenia. Patients with MDS are at risk for symptomatic anemia, infection, and bleeding, as well as a variable risk of progression to acute leukemia. With the exception of stem cell transplant, the standard treatments for MDS are rarely curative, and relapse rates are significant. MDS patients with cytopenias who fail standard therapies require regular blood or platelet transfusions which are expensive and inconvenient, and are at risk for serious bleeding complications.

Thrombopoietin (TPO) is the principal regulator of platelet production by megakaryocytes in the bone marrow. A 2nd generation TPO-agonist, eltrombopag (Promacta ) has been shown to increase platelets in thrombocytopenic patients with chronic immune thrombocytopenic purpura (ITP). Eltrombopag is administered orally, is well-tolerated, and is FDA approved for the treatment of thrombocytopenia in patients with chronic ITP who failed to respond to standard treatment.

Because the management of MDS patients with persistent cytopenias remains unsatisfactory and novel therapeutic approaches are needed, we propose a non-randomized, pilot, phase II study of eltrombopag in low to Int-2 risk MDS subjects with thrombocytopenia and anemia cytopenias who are either untreated or cytopenias that persist despite treatment with standard therapies to assess its utility in these settings.

Subjects will initiate study medication at an oral dose of 50 mg/day (25 mg/day for East Asians), which will be adjusted as clinically indicated to the lowest dose that maintains a stable platelet count greater than or equal to 20,000/microL above baseline while maximizing tolerability. Treatment response will be any increase in a cytopenia, in the lineage that fulfilled eligibility criteria for enrollment and will be defined as: (a) platelet count increases to 20,000/microL above baseline at 16 or 20 weeks , or stable platelet counts with transfusion independence for a minimum of 8 weeks in subjects who were previously transfusion dependent; (b) erythroid response for subjects with a pretreatment hemoglobin of less than 9 g/dL will be defined as an increase in hemoglobin by greater than or equal to 1.5g/dL without packed red blood cell (PRBC) transfusion support, or a reduction in the units of PRBC transfusions by at least 50% during the eight consecutive weeks prior to response assessment compared with the pretreatment transfusion number in the previous 8 weeks; (c) neutrophil response will be defined in those with a pretreatment absolute neutrophil count (ANC) of \< 0.5 times 10(9)/L as at least a 100% increase or an absolute increase \> 0.5 times 10(9)/L. Subjects meeting a response may remain on the extended access until they meet an off study criteria or the study is closed.

Subjects with response at 16 or 20 weeks may be consented for entry into the extended access part of the trial. In the event that a subject is transfused platelets for a count \>10,000/microL without a medical indication during the study period, the subject may continue on study drug and the response assessment may be extended for an additional 4 weeks to week 20, at the discretion of the principal investigator. Subjects with evidence for a clinical response in any lineage at 16 weeks but not yet meeting full primary endpoint response criteria, and who are tolerating investigational treatment, may receive an additional 4 weeks of eltrombopag and be reassessed after 20 weeks. At that time, if they meet primary endpoint response criteria, they will be eligible to enter the extended access part of the study. If they do not meet primary endpoint response criteria, eltrombopag will be discontinued.

Primary objective is to assess the efficacy of eltrombopag in patients with low to Int-2 risk MDS. Safety of eltrombopag in this subject population will be assessed concurrently.

Secondary objectives include the toxicity profile of extended treatment with eltrombopag (treatment longer than 4 months), reduction in incidence and severity of bleeding episodes, and response following extended access to study drug (treatment longer than 4 months).

The primary endpoint will be the portion of drug responders as defined by changes in the platelet count and/or platelet transfusion requirements, or the proportion of subjects who meet erythroid response, or neutrophil response criteria.. Platelet response is defined as platelet count increases to 20,000/microL above baseline at 16 or 20 weeks, or stable platelet counts with transfusion independence for a minimum of 8 weeks. Erythroid response for subjects with a pretreatment hemoglobin of less than 9 g/dL will be defined as an increase in hemoglobin by greater than or equal to 1.5g/dL without packed red blood cell (PRBC) transfusion support, or a reduction in the units of PRBC transfusions by at least 50% during the eight consecutive weeks prior to response assessment compared with the pretreatment transfusion number in the previous 8 weeks. Neutrophil response will be defined in those with a pretreatment absolute neutrophil count (ANC) of \<0.5 times 10(9)/L as at least a 100% increase or an absolute increase \> 0.5 times 10(9)/L. Subjects with an erythroid, and/or neutrophil response at 16 weeks may continue study medication (extended access) until they meet an off study criteria. Subjects with erythroid, or neutrophil response at 16 weeks may continue study medication for an additional 4 weeks (to ensure eligibility) prior to being consented for entry into the extended access part of the trial. Patients may remain on the extended access until they met an off study criteria.

The toxicity profile will be measured using the CTCAE Version 4.0 criteria.

Secondary endpoints will include incidence of grade 2 or higher bleeding events as measured by CTCAE v. 4.0; changes in serum thrombopoietin level, measured at 4 months; and progression to higher risk MDS as measured by IWG criteria.

Eligibility Criteria:
* INCLUSION CRITERIA:

Diagnosis of MDS, with WHO classification of refractory anemia, refractory cytopenia with unilineage dysplasia (RCUD), RARS, RCMD-RS, or RCMD.

IPSS risk scores of low, intermediate-1, or intermediate-2.

Platelet count less than or equal to 30,000/ microL or platelet-transfusion-dependence (requiring at least 4 platelet transfusions in the 8 weeks prior to study entry); or hemoglobin less than 9.0 gr/dL or red cell transfusion-dependence (requiring at least 4 units of PRBCs in the eight weeks prior to study entry) OR ANC less than or equal to 500

Age greater than or equal to 18 years old

Treatment naive or off all other treatments for MDS (except stable dosing of filgrastim \[G-CSF\], erythropoietin, and transfusion support) for at least four weeks. G-CSF can be used before, during and after the protocol treatment for subjects with documented neutropenia (\<500/UI) as long as they meet the criteria for other cytopenia as stated above. G-CSF must be held for 3 weeks prior to enrollment bone marrow biopsy and prior to each study assessment bone marrow biopsy, unless clinically indicated to avoid infections per PI discretion.

Adequate liver function, as evidenced by total serum bilirubin less than or equal to 1.5 times the upper limit of normal patients with Gilbert's disease are eligible, provided intermittent indirect hyperbilirubinemia, AST or ALT less than or equal to 5 times the upper limit of normal.

A serum creatinine concentration less than or equal to 2 times ULN

EXCLUSION CRITERIA:

WHO classification of chronic myelomonocytic leukemia (CMML), RAEB-1, RAEB-2, AML

Treatment with horse or rabbit ATG or Campath within 6 months of study entry

Subjects with liver cirrhosis including subjects infected with Hepatitis B or C

Subjects with HIV

Infection not adequately responding to appropriate therapy

History of malignancy treated with chemotherapy and cytogenetic abnormalities suggestive of secondary myelodysplasia.

Moribund status or concurrent hepatic, renal, neurologic, pulmonary, infectious, or metabolic disease of such severity that it would preclude the patient s ability to tolerate protocol therapy

Life expectancy of less than 3 months

Hypersensitivity to eltrombopag or its components

Female subjects who are nursing or pregnant or are unwilling to take oral contraceptives or refrain from pregnancy if of childbearing potential

Unable to understand the investigational nature of the study or give informed consent or does not have a legally authorized representative or surrogate that can provide informed consent per section