New FDA approvals

These drugs recently received final approval from the U.S. Food and Drug Administration (FDA):

Gefitinib (Iressa) by AstraZeneca LP. The FDA has approved gefitinib (Iressa) tablets as a single-agent treatment for patients with advanced non-small cell lung cancer (NSCLC). Gefitinib is being approved as a treatment for patients whose cancer has continued to progress despite treatment with platinum-based and docetaxel chemotherapy, two drugs that are the standard of care for this disease.

Gefitinib was reviewed and approved under the FDA’s accelerated approval program. As required by the accelerated approval regulations, gefitinib’s developer will perform additional studies to verify the drug’s clinical benefit.

Gefitinib was developed to block growth-stimulatory signals in cancer cells. These signals are mediated in part by enzymes called tyrosine kinases. Gefitinib blocks several of these tyrosine kinases, including the one associated with epidermal growth factor receptor.

The FDA based the approval on the results of a study of 216 patients with NSCLC, including 142 patients with refractory disease. The response rate (defined as at least 50% tumor shrinkage lasting at least one month) was about 10%. There were more dramatic responses in some patients, and the median duration of response was seven months.

There appeared to be substantial differences in response rates in subsets of patients, with higher response rates for women (about 17%) and patients with adenocarcinoma, and lower response rates seen in men (about 5%) and smokers.

Common side effects reported with gefitinib in clinical trials were nausea, vomiting, diarrhea, rash, acne, and dry skin. Gefitinib may cause fetal harm when administered to pregnant women. A concern also has been raised about the occurrence of serious and sometimes fatal interstitial lung disease in patients treated with gefitinib. The FDA researched those reports and decided that this rare but serious toxicity of gefitinib does not outweigh the benefits demonstrated in patients with advanced NSCLC.

Gemifloxacin (Factive) by GeneSoft Pharmaceuticals. The FDA has approved gemifloxacin (Factive), a fluoroquinolone antibiotic, for the treatment of mild-to-moderate community-acquired pneumonia (CAP) and acute bacterial exacerbation of chronic bronchitis (AECB).

Gemifloxacin has been tested in global clinical trials in nearly 10,000 people. AECB trials have shown that five days of gemifloxacin is as effective as other marketed products. In CAP trials, gemifloxacin given for seven days is effective treatment for patients.

Gemifloxacin should be used only to treat infections that are proven or strongly suspected to be caused by bacteria. The most common side effects include diarrhea, rash, nausea, and headache. Rash is generally mild-to-moderate in nature and is more likely to occur if taken for longer than the recommended course.

New indication for sirolimus (Rapamune) by Wyeth Pharmaceuticals. The FDA has approved a new indication for the immunosuppressant agent sirolimus (Rapamune). Sirolimus was approved in 1999 for the prophylaxis of organ rejection in renal transplant patients in combination with cyclosporine and corticosteroids. The new indication provides for withdrawal of cyclosporine from the immunosuppressive regimen two to four months after renal transplantation in patients at low-to-moderate immunologic risk. The safety and efficacy of cyclosporine withdrawal in high-risk patients have not been adequately studied and is therefore not recommended for these patients. Rapamune is available in both 1 mg and 2 mg tablet formulations.