The U.S. Food and Drug Administration (FDA) has approved Rituxan (rituximab) to treat certain patients with chronic lymphocytic leukemia (CLL), a slowly progressing blood and bone marrow cancer.

Rituxan, an anti-cancer drug, is intended for patients with CLL who are beginning chemotherapy for the first time and for those who have not responded to other cancer drugs for CLL. Rituxan is administered with two other chemotherapy drugs, fludarabine and cyclophosphamide.

CLL primarily affects people older than 50 and arises from a group of white blood cells known as B-cells—part of the body’s immune system. Each year, about 16,000 people are diagnosed with and 4,400 die from CLL.

“Rituxan is the third drug approved for the treatment of CLL since 2008 and underscores FDA’s commitment to expediting the development and approval of drugs for patients with serious and life-threatening diseases,” said Richard Pazdur, M.D., director, Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research.

FDA approved Arzerra (ofatumumab) in October 2009 for patients whose cancer is no longer being controlled by other forms of chemotherapy and Treanda (bendamustine) in March 2008 for patients with CLL who had not received prior treatment.

Rituxan is a monoclonal antibody. It is manufactured through biotechnology methods rather than by the human body’s own immune system. The drug binds to the surface of cancer cells, making it easier for the patient’s immune system to attack the cancer cell as if it were a foreign pathogen.

The safety and effectiveness of Rituxan was evaluated in two studies that measured progression-free survival, defined as the time a patient in the study lived without the cancer progressing.

In one study of 817 patients who had not received any prior chemotherapy, progression-free survival was eight months longer for those receiving Rituxan plus chemotherapy than for those who received chemotherapy alone. In another study of 522 persons whose cancer had progressed following other chemotherapy drugs, progression-free survival was five months longer for those who received Rituxan plus chemotherapy.

The FDA analyzed the data on patients 70 years of age and older who had received Rituxan and found no evidence that adding the drug to chemotherapy benefitted elderly patients compared to receiving chemotherapy alone. However, there was also no evidence that Rituxan was harmful to elderly patients.

Rituxan carries a Boxed Warning for infusion reactions, which can occur during infusion or within 24 hours afterwards. Some 59 percent of patients treated with Rituxan for CLL experienced an infusion reaction that resembled an allergic reaction (e.g., hives, low blood pressure, chills, fever, and nausea).

A decrease in infection-fighting, normal white blood cells was also commonly observed in patients enrolled in the Rituxan clinical trials.

Other Boxed Warnings for Rituxan include rashes and sores in the skin and mouth; progressive multifocal leukoencephalopathy (PML), a brain infection that is generally fatal; and tumor lysis syndrome, which results from the death of a large number of tumor cells in a short period of time. When the tumor cells are killed by the drug, they release toxins into the bloodstream that can cause acute kidney injury and increase the levels of potassium and phosphate in the blood.

Rituxan is manufactured by San Francisco based-Genentech, a member of the Roche Group.

Source: FDA (2/18/2010)