Anemic Patients With Myelodysplastic Syndromes Gain Long-Term Benefits From Erythropoietin and Myeloid Growth Factor Hormones

Myelodysplastic Syndromes (MDS), a group of blood disorders that can lead to acute myeloid leukemia (AML) in some patients, often cause severe anemia (when the body lacks a sufficient number of functional red blood cells). While certain treatments can help manage the symptoms of anemia, some studies have suggested that they may lead to complications.

Now a new study demonstrates that MDS patients with anemia may benefit from treatment with an erythropoietin (EPO)-based regimen plus supportive care without added complications as compared with those receiving supportive care alone. The study will appear in the September 17 issue of Blood, the official journal of the American Society of Hematology.

The phase III prospective, randomized trial, conducted by research teams of the Eastern Cooperative Oncology Group, was designed to evaluate the efficacy and safety of EPO with or without myeloid growth factor treatment (G-CSF, or granulocyte colony-stimulating factor) and supportive care (SC) with red blood cell transfusions for patients with early-stage MDS (n=53), in comparison to supportive care alone (n=57).

For the study, the researchers followed MDS treatment and dosing guidelines recommended by the National Comprehensive Cancer Network, which include managing anemia with erythropoiesis-stimulating agents (ESAs) such as EPO. EPO is a drug that imitates the action of the hormone erythropoietin, which stimulates the body to produce more red blood cells. Generally, therapy with G-CSF interacts with EPO treatment synergistically to improve erythroid (red blood cell) responses, especially in MDS patients that do not respond to EPO alone.

"EPO is a recommended treatment for MDS, but the combination with G-CSF and supportive care required comparative studies in this patient population," according to lead study author Peter Greenberg, MD, Professor of Medicine, Stanford University Cancer Center. "Our goal was to manage anemia while not increasing the risk of transformation to leukemia, and we undertook this study to understand if this combination might be successfully utilized in these patients."

The results of the study proved successful for this group of patients with lower-risk MDS and anemia. After the first course of therapy, 36 percent of patients in the EPO arm responded to treatment, compared with only 9.6 percent in the SC alone arm. After subsequent courses, 47 percent responded in the EPO arm. Researchers then followed both patient groups for a median of 5.8 years to determine their long-term response to treatment. Responders to EPO experienced increased survival in comparison to the non-responders (5.5 vs. 2.3 years) and significantly improved physical, emotional, and functional well-being, reduced fatigue, and improved overall quality of life.

The research team otherwise found no statistically significant differences in overall survival of patients between the EPO and SC arms (3.1 vs. 2.6 years) or the incidence of transformation to AML (7.5 vs. 10.5 percent of patients, respectively), suggesting long-term safety of the EPO treatment regimen.

The study results also indicated that the combination of EPO plus G-CSF was beneficial for patients who either did not respond initially to EPO or who experienced a delayed response. Furthermore, higher doses of EPO seemed to prove valuable for a proportion of patients who initially failed to respond. Importantly, the outcomes suggested long-term tolerance to the treatment combination, with a low overall incidence of adverse events. Specifically, the researchers found no significant treatment-related increase in incidence of either cardiovascular or thrombotic (clotting) events or transformation to AML in the patients who received EPO alone or with G-CSF, as compared with those in the SC arm.

Recently, the FDA has issued alerts regarding the use of ESAs, noting increased mortality, possible tumor promotion, and thromboembolic events that have been observed in some studies of non-MDS patients receiving ESAs. However, other studies of patients with solid tumors receiving chemotherapy did not demonstrate an adverse effect of ESAs on survival.

"We believe the data suggest that the negative effects of cytokines, like ESAs, demonstrated in some studies of other diseases may relate to biologic and clinical features or the specific treatments associated with the differing disorders studied," said Dr. Greenberg. "Findings from this study demonstrate the relative safety and efficacy of EPO plus G-CSF for treating anemic lower-risk MDS patients and may be considered as part of future treatment recommendations for the use of this class of therapies."

For Aditional Information

• Treatment of myelodysplastic syndromes patients with erythropoietin
  with or without granulocyte colony-stimulating factor: results of a
  prospective randomized phase III trial by the Eastern Cooperative
  Oncology Group (E1996), Blood First Edition Paper, prepublished online
  June 29, 2009
• American Society of Hematology/American Society of Clinical Oncology
  2007 Clinical Practice Guideline Update on the Use of Epoetin and
  Darbepoetin
• ASH Model Policy on Indications for ESA Treatment for Patients with MDS

Advisory Committee Recommends Randomized Trial to Support Proposed Indication for Clofarabine in Adult AML

The FDA’s Oncologic Drugs Advisory Committee voted 9 to 3 that a randomized, controlled trial is needed to support the currently proposed label expansion for clofarabine (Clolar® , Genzyme) in adult myeloid leukemia (AML). Clofarabine is currently approved as the standard of care for pediatric acute lymphoblastic leukemia (ALL) patients who have relapsed or have refractory disease after at least two prior regimens. The drug has an Orphan Drug designation.

The committee found that the single-arm clinical study results submitted to support the label expansion showed clofarabine was an active agent in acute AML patients, but concluded that a randomized clinical trial should be necessary to better interpret clofarabine’s efficacy and safety in the proposed patient population.

“I am happy that the three panel members who have significant experience in treating older adults with AML recognized the value of clofarabine in these patients and did not see the need for a randomized trial,” said Harry P. Erba, M.D., Ph.D., University of Michigan, one of the co-principal investigators of the CLASSIC II study.

“The panel indicated that it wasn’t an easy decision to vote for a randomized trial as Clolar was clearly active in these patients,” said Mark Enyedy, president of Genzyme Oncology and Multiple Sclerosis. “The requirement for a randomized control trial as a standard of evidence was a major focus of the discussion. We remain committed to the clinical development of Clolar in this patient population with high unmet medical need.”

Genzyme is conducting a randomized Phase 3 trial comparing clofarabine in combination with cytarabine to cytarabine alone in relapsed and refractory adult AML patients 55 years old or older. The trial continues to exceed patient accrual expectations, and results are expected in 2011. Clofarabine is also being investigated in clinical trials by most of the leading AML experts and major cooperative leukemia investigation groups in the United States and Europe.

The CLASSIC II study, discussed at the Oncologic Drugs Advisory Committee (ODAC), analyzed 112 adult AML patients aged 60 years and older with one or more unfavorable prognostic factors, including age 70 years or older, an antecedent hematologic disorder (AHD), poor performance status, or intermediate or unfavorable cytogenetics. As reported in peer-reviewed literature, and discussed by a separate panel of AML experts who recommended the trial, these risk factors predict poor outcomes in older patients with conventional induction therapy.

Patients in the trial had a 45.5 percent overall remission rate, including a 37.5 percent complete remission (CR) rate, and remission rates were consistent regardless of the type or number of unfavorable risk factors. The study also found that clofarabine remissions were durable. Durable CR is accepted as an established surrogate for clinical benefit in patients with acute leukemias. The median duration of remission in overall responders (CR+CR with incomplete platelet recovery) was estimated as 52 weeks (12 months). Most patients who responded to treatment achieved remission after one cycle.

The safety profile of clofarabine in the Phase 2 study was generally predictable and manageable. The all-cause induction 30-day mortality was 9.8 percent and was consistent regardless of the presence or number of unfavorable prognostic factors. The safety findings were consistent with those for the approved clofarabine pediatric ALL indication. The most commonly occurring adverse reactions included nausea, vomiting, diarrhea, febrile neutropenia, rash, headache, fever, fatigue, hypokalemia, pneumonia, anorexia, pruritus, increased liver transaminases, neutropenia, thrombocytopenia, mucosal inflammation.

The American Cancer Society estimates that approximately 12,810 people will be diagnosed with AML in the United States in 2009. About 70 percent of these patients will die from the disease, and almost all will be adults. The median age of a patient with AML is about 67 years. As an acute disease, AML progresses rapidly and is typically fatal within weeks or months if left untreated.