Enrollment in Avastin breast cancer study halted

Swiss drug developer Roche said Friday six cases of patients with heart failure symptoms prompted a halt to enrollment in a National Cancer Institute sponsored study of its blockbuster drug Avastin.

The U.S. National Cancer Institute and U.S. Eastern Cooperative Oncology Group, which is conducting the study, told Roche it suspended adding new patients to the late-stage study because of the heart failure symptoms in the early-stage breast cancer patients. Symptoms include shortness of breath and fatigue, along with swelling in certain parts of the body.

The study focuses on Avastin's effectiveness as an adjuvant in combination with chemotherapy. The drug is already approved to treat various stages of colon, lung, brain, and kidney cancer and is one of Roche's biggest moneymakers.

Roche said the rate of heart failure symptoms is consistent with Avastin's side effects.

The study is designed to test for cardiovascular safety and focused on the first 200 patients enrolled, from which the six patients showed heart failure symptoms. The study was designed for a halt in enrollment if six of the first 200 patients showed signs of heart failure.

Five patients have since returned to normal levels and Roche said it is waiting for information on the sixth patient. Roche said the rate of heart failure is consistent Avastin's profile.

Moving ahead, the study's safety board is evaluating the data and will determine the next steps. There are currently 3,439 patents enrolled in the study and will have to give their consent to continue dosing after being given the updated information.

The study goal was to enroll 4,950 patients.

In April, Avastin failed a similar late-stage study focused on early-stage cancer and the company said it would continue study the drug's effectiveness in combination with chemotherapy for other types of cancer.

Roche had been partners with South San Francisco, Calif.-based Genentech on Avastin prior to paying $46.8 billion for the biotechnology company. Avastin, which is approved as a treatment for various stages of colon, lung, brain, and kidney cancer, was Genentech's biggest seller. It is now one of Roche's most lucrative drugs, reaching U.S sales $2.69 billion in 2008. Wall Street has projected the drug could exceed $10 billion in sales by 2015.