National Cancer Institute NCI Cancer Bulletin: A Trusted Source for Cancer Research News
February 23, 2010 • Volume 7 / Number 4

FDA Update

Initiative Aims to Reduce Unnecessary Radiation Exposure from Medical Imaging

On February 8, the FDA announced a new initiative to reduce unnecessary radiation exposure from three widely used types of medical imaging: computed tomography (CT), nuclear medicine studies (including positron emission tomography, or PET), and fluoroscopy.

Recently, researchers have raised concerns that overuse of CT and other diagnostic procedures that use ionizing radiation, as well as a lack of oversight of the amount of radiation used in these tests, may contribute to an unnecessary cancer risk in the general population.

“The amount of radiation Americans are exposed to from medical imaging has increased dramatically over the past 20 years,” said Dr. Jeffrey Shuren, director of the FDA’s Center for Devices and Radiological Health, in a press release announcing the initiative. “The goal of FDA’s initiative is to support the benefits associated with medical imaging while minimizing the risks.”

The initiative will promote the safe use of medical imaging devices (including optimizing the radiation dose used during each procedure), support informed decision making (including appropriately justifying the use of procedures involving radiation exposure), and increase patients’ awareness of their exposure to radiation.

The FDA will begin by issuing targeted requirements for manufacturers of CT and fluoroscopic devices to incorporate new safeguards into the design of the machines, develop safer technologies, and provide appropriate training to support safe use by practitioners. The agency will solicit input on the details of these requirements at a public meeting being held on March 30 and 31.

Rituximab Approved for Chronic Lymphocytic Leukemia

The FDA has approved the use of rituximab (Rituxan) to treat patients with chronic lymphocytic leukemia (CLL). The approval covers the drug’s use with the chemotherapy drugs fludarabine and cyclophosphamide in patients who have yet to undergo treatment for CLL or whose disease is not responding to other approved treatments. Rituximab is a monoclonal antibody that targets a specific antigen, CD20, on cancer cells. By binding to the antigen, the drug triggers an immune response in the body against cells that express CD20.

The agency’s approval is based on the results of two clinical trials which showed that, in either treatment setting, the combination of rituximab and the two chemotherapy drugs led to statistically significant improvements in patient survival without tumor growth, known as progression-free survival. Complete response rates—that is, no visible signs of cancer—in both trials were approximately doubled in patients who received rituximab, fludarabine, and cyclophosphamide compared with those who received only fludarabine and cyclophosphamide. However, the incidence of several serious side effects was also significantly higher in patients who received all three drugs.

This is the third drug approved for treating patients with CLL since 2008, the FDA noted in a statement. In March 2008, the FDA approved bendamustine (Treanda) for the initial treatment of patients with CLL, and in October 2009 ofatumumab (Arzerra) was approved for patients with CLL whose disease is no longer responding to treatment.

FDA Announces Risk Management Program for Anemia Drugs

Under a new FDA requirement, health care providers who prescribe anti-anemia drugs called erythropoiesis-stimulating agents, or ESAs, to cancer patients must enroll in a risk management program. The program requires that health care providers be trained on the drugs’ appropriate use in cancer patients and document that they discussed with each patient the drugs’ risks, benefits, and FDA-approved uses. Providers must also give patients a medication guide that explains the risks and benefits of ESAs.

The new requirements are part of a Risk Evaluation and Mitigation Strategy (REMS) program to be implemented by the drugs’ manufacturer, Amgen Inc., under an agreement with the FDA. ESAs include epoetin alfa (Procrit/Epogen) and darbepoetin alfa (Aranesp).

The change is the latest in a series of regulatory actions taken by the FDA in response to data from studies involving patients with cancer, which found that the drugs were associated with increased mortality risk and accelerated tumor growth.

The agency understands that the requirements “will create new responsibilities for busy health care providers,” said Dr. Richard Pazdur, director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research (CDER), during a press briefing on the new program. But in patients with cancer, Dr. Pazdur continued, the risk-benefit balance of treatment with ESAs can be “delicate.” In fact, because of the potential risks associated with their use, the drugs are no longer indicated for patients receiving chemotherapy in whom the expected outcome is cure. The risk management program, he stressed, will help patients “make the best possible choice given their particular situation.”

Clinicians who wish to prescribe the drugs to cancer patients must complete an Amgen-administered training and certification program called APPRISE. Health care providers who are not enrolled in APPRISE will be barred from prescribing the drugs for cancer patients.

Individual hospitals must also enroll in the APPRISE program and establish a system for ensuring that providers in the hospital who prescribe ESAs are enrolled and comply with the program. Providers and hospitals can start enrolling in APPRISE beginning on March 24 and have up to 1 year to enroll and become certified. Re-enrollment is required every 3 years.

The REMS program for ESAs is “breaking new ground for the FDA,” explained Dr. Patricia Keegan, director of CDER’s Division of Biologic Oncology Products. The agency has never required a single REMS that covers multiple agents, she noted, or that covered only a single indication for an approved drug that has multiple indications. ESAs are also approved to manage anemia related to the treatment of kidney disease and HIV.