Arzerra drug approved by FDA for treating chronic lymphocytic leukemia

Oct 27 2009

Arzerra is approved for patients with CLL whose cancer is no longer being controlled by other forms of chemotherapy.

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

Arzerra is a monoclonal antibody, a type of biotechnology product. Antibodies that occur in nature are produced by the immune system in response to invaders. Arzerra binds to a specific protein found on the surface of both normal and malignant B cells, making the cells more susceptible to immune system attack. 

The product was approved under the FDA's accelerated approval process, which allows earlier approval of drugs that meet unmet medical needs. Products may receive accelerated approval based on a surrogate endpoint, such as a reduction in the size of the tumor or decrease in the number of cancerous white cells or in an enlarged spleen or lymph nodes. These indirect measures for clinical outcomes are considered reasonably likely to predict that the drug will allow patients to live longer or with fewer side effects of a disease.

"The approval of Arzerra illustrates FDA's commitment to using the accelerated approval process to approve drugs for patients who have limited therapeutic options," said Richard Pazdur, M.D., director of the Office of Oncology Drug Products in the FDA's Center for Drug Evaluation and Research.

The accelerated approval process requires further study of the drug. The manufacturer is currently conducting a clinical trial in CLL patients to confirm that the addition of Arzerra to standard chemotherapy delays the progression of the disease.

Arzerra's effectiveness was evaluated in 59 patients with CLL whose disease no longer responded to the available therapies.

The product's safety was evaluated in 181 patients in two studies in patients with cancer. Common side effects included a decrease in normal white blood cells, pneumonia, fever, cough, diarrhea, lower red blood cell counts, fatigue, shortness of breath, rash, nausea, bronchitis and upper respiratory tract infections.

The most serious side effects of Arzerra are increased chance of infections, including progressive multifocal leukoencephalopathy (PML), a brain infection that is generally fatal. Patients at high risk for Hepatitis B should be screened before being treated with Arzerra. Patients with evidence of inactive hepatitis should be monitored for re-activation of the infection during and after completing treatment.

Arzerra is manufactured by London-based GlaxoSmithKline.