Avastin, Similar Cancer Drugs, May Increase Risk of Aortic Dissection: Study

The findings of a new study raise concerns about the side effects of Avastin and similar cancer drugs, indicating that the medications may cause users to face an increased risk of aortic dissection, a serious and potentially life-threatening condition. 

In a research letter published last week in the medical journal Circulation, Japanese scientists indicate that they have found an association between a class of cancer drugs known as vascular endothelial growth factor pathway inhibitors (VPIs) and aortic dissections. The class includes Avastin, Sutent, Nexavar and similar drugs.

An aortic dissection involves a tear inside of the aorta, which causes blood to low between the layers, forcing them apart. It is similar to an aortic aneurysm, which occurs when the walls of the artery weaken and an abnormal bulge develops. The conditions are associated with severe chest or back pain, which can quickly lead to death or severe, long-term injury.

Researchers said they knew that Avastin and drugs of the same class can cause hypertension, which is an indicator of aortic dissection risk. To look for an association, they used data from the Japanese Adverse Drug Event Report database and found 91,055 patients with underlying malignant neoplasms, or solid tumors, of which 16,441 were treated with VPIs from April 2004 through October 2015.

According to the findings, researchers discovered 59 cases of aortic dissection among the cancer patients, and 49 of those cases were associated with the use of VPIs. Avastin was linked to the most cases, with 21 aortic dissections occurring among Avastin patients. Only 10 patients who were not given Avastin, Sutent or a similar drug suffered aortic dissections during the more than 10-year period, the researchers found.

The study found that hypertension appeared to be a significant factor, with 25 of the 49 aortic dissection patients in the VPI group showing signs of baseline hypertension. There was also a higher percentage of hypertension among patients given Avastin and drugs of the same class than in patients given other types of cancer drugs.

“Our analysis found a signal for an increased risk of aortic dissection during systemic exposure to VPIs,” the researchers concluded. “This finding appears to be a class effect.”

Avastin (bevacizumab) was approved by the FDA in 2004 for treatment of non-small cell lung cancer and colorectal cancer when combined with chemotherapy. It was developed by Genentech, which was later acquired by Roche. The drug works by restricting blood flow to tumors; starving them. Avastin sales reached nearly $6 billion in 2009.