Panel Gives Platelet Growth Factor Nod of Approval

MADISON, NJ—The Biological Response Modifiers Advisory Committee unanimously recommended that the Food and Drug Administration approve Neumega (recombinant human inter-leukin-11 or rhIL-11), Genetics Institute’s platelet growth factor. Genetics Institute is a subsidiary of American Home Products Corporation.

Neumega is indicated for the prevention of recurrent severe chemotherapy-induced thrombocytopenia. The committee also unanimously determined that the benefits of Neumega outweigh the risks of therapy.

In an integrated analysis of two pivotal randomized studies involving 121 evaluable patients treated with Neumega, 50 µg/kg, or placebo, Neumega reduced the incidence of severe thrombocytopenia due to chemotherapy.

The relative risk of patients treated with Neumega receiving any platelet transfusions was 0.7. Thus, Neumega reduced the need for platelet transfusions by approximately 30%, compared with placebo. The Neumega group received fewer platelet transfusions (mean, 1.4) than the placebo group (mean, 2.8).

In one of these studies involving previously transfused patients, transfusion requirements in the Neumega-treated group decreased even while the chemotherapy doses were maintained.

Well Tolerated

Treatment with Neumega was generally well tolerated by participants in the clinical trials, the company said. Most adverse effects were mild to moderate and reversible.

Many of these effects were attributable to fluid retention, resulting in a moderate increase in plasma volume, and were easily managed. Common side effects associated with Neumega treatment included peripheral edema, dyspnea, tachycar-dia, and conjunctival infection. Less common adverse events associated with the agent were palpitations, oral moni-liasis, and pleural effusions.

“If approved, rhIL-11 will be important in managing patients who receive chemotherapy that tends to suppress the development of platelets,” said Michael S. Gordon, MD, associate professor of medicine, Indiana University School of Medicine. “Avoiding thrombocytopenia may allow planned chemotherapy to continue without disruption,” he added, “while protecting patients from the risk of bleeding and eliminating or reducing the risks of platelet transfusions.”

The committee concluded that efficacy of Neumega was shown in patients who previously experienced severe platelet depletion while receiving a variety of chemotherapy regimens. The committee considered the data available at this time to be insufficient to endorse administration of Neumega starting with the initial cycle of chemotherapy.

“We are, of course, pleased with the advisory panel’s recommendation,” said L. Patrick Gage, PhD, president of Genetics Institute, Inc. “We look forward to working with the FDA to gain marketing clearance for Neumega."