With clinical trials of cancer drug Avastin showing that the drug apparently does little to help enhance the life-span of breast cancer patients or to effectively control their tumors, the US Food and Drug Administration (FDA) Friday withdrew the approval of the drug as a treatment for those patients whose breast cancer has spread to other organs.

Revealing that the results of clinical trials of Avastin as a treatment for metastatic breast cancer were "disappointing," FDA commissioner Dr. Margaret Hamburg elaborated that it has been found that Avastin actually exposes breast cancer patients to hemorrhage, acute high blood pressure, and other such potentially serious side-effects.

The FDA's Friday ruling pertaining to Avastin has come almost five months after the recommendations of an FDA advisory committee which said that the federal agency should revoke its approval of the drug for patients of breast cancer.

Despite the fact that clinical trial results have rekindled years-long apprehensions about the effectiveness of Avastin in treating breast cancer, Hamburg said that the FDA did not "lightly" reach the decision about revoking its approval of the drug for metastatic breast cancer.

Explaining the raison d'etre behind the FDA's decision, Hamburg said that fast-tracked drugs like Avastin necessitate a rigorous and continued review, and that "withdrawal is an essential component of the accelerated approval program."