National Cancer Institute NCI Cancer Bulletin: A Trusted Source for Cancer Research News
November 2, 2010 • Volume 7 / Number 21

FDA Update

Labeling Change Includes Warning for a Class of Prostate Cancer Drugs

The FDA has announced drug labeling changes for gonadotropin-releasing hormone (GnRH) agonists, a class of drugs used to treat prostate cancer. The changes add warnings about the potential risk of cardiovascular events and diabetes in men treated with these androgen deprivation therapy drugs.

In May, the FDA said that a preliminary and ongoing analysis found that patients receiving GnRH agonists were at a slightly increased risk for diabetes, heart attack, stroke, and sudden death. In its latest announcement, the FDA noted that health care professionals should evaluate patients for risk factors for these diseases and that patients who are receiving treatment with these drugs should undergo periodic monitoring of blood glucose and/or glycosylated hemoglobin.

GnRH agonists are marketed under the brand names Eligard, Lupron, Synarel, Trelstar, Vantas, Viadur, and Zoladex. Several generic products are also available.

Dasatinib Approved as First-line Treatment for Chronic Myelogenous Leukemia

The FDA has granted accelerated approval for dasatinib (Sprycel) as a first-line treatment for patients with chronic phase chronic myelogenous leukemia (CML), the agency announced last week. Like two other therapies already approved to treat CML, imatinib (Gleevec) and nilotinib (Tasigna), dasatinib targets the molecular driver of CML, a fusion of the genes BCR and ABL. This fusion gene produces a protein that spurs the overdevelopment of white blood cells that is the hallmark of CML.

The accelerated approval was based on clinical trial results reported at the American Society of Clinical Oncology annual meeting in June. The results showed that, after 12 months of follow-up, patients who received dasatinib had higher rates of complete response than patients who received imatinib. Under accelerated approval, the FDA can approve a drug that, based on the available data, the agency believes will address an unmet medical need. Under the approval, Bristol-Myers Squibb, which manufactures dasatinib, is required to collect longer-term efficacy and safety data on the drug.

Dasatinib was already approved by the FDA to treat CML patients who do not respond to or who develop resistance to other therapies, including imatinib.

Trastuzumab Becomes First Targeted Therapy Approved for Stomach Cancer

The FDA has also approved trastuzumab (Herceptin) for the treatment of stomach cancer. The approval covers the use of trastuzumab in combination with chemotherapy in patients with metastatic gastric or gastroesophageal junction adenocarcinoma whose tumors overexpress the HER2 protein.

The decision makes trastuzumab the first targeted therapy for stomach cancer, a disease for which there have been few treatment advances over the past 2 decades. The FDA’s decision was based on results from the nearly 600-patient ToGA trial, in which patients whose tumors were HER2-positive received trastuzumab in combination with chemotherapy (cisplatin and either capecitabine or fluorouracil) or chemotherapy alone.

Results from the trial published last August in The Lancet showed a 2.7-month improvement in median overall survival for patients in the trastuzumab arm. According to the FDA, an updated analysis found a 2.4-month survival improvement, with patients whose tumors tested most strongly for HER2 overexpression by immunohistochemistry receiving the most robust survival benefit.