Two new drugs along with a companion diagnostic test were recently approved by the Food and Drug Administration.
Xofigo (radium RA 223 dicholoride) was approved to treat patients with symptomatic metastatic castration-resistant prostate cancer that has spread to the bones but not to other organs, and patients who have previously received medical or surgical therapy to lower testosterone.
The drug, made by Bayer Pharmaceuticals, is an alpha particle-emitting radioactive therapeutic agent that binds with minerals in the bone to deliver radiation directly to bone tumors, thus limiting damage to surrounding normal tissues.
“Xofigo is the second prostate cancer drug approved by the FDA in the past year that demonstrates an ability to extend the survival of men with metastatic prostate cancer,” Richard Pazdur, MD, Director of the FDA's Office of Hematology and Oncology Products, said in a news release.
In August 2012, the FDA approved Xtandi to treat patients with metastatic castration-resistant prostate cancer that has spread or recurred, even with medical or surgical therapy to minimize testosterone and who have previously been treated the chemotherapy drug docetaxel (OT 9/25/12 issue)
The new approval occurred more than three months ahead of the product's prescription drug user fee goal date of Aug. 14, the date the FDA was scheduled to complete review of the drug application. The drug was reviewed under the FDA's priority review program, which provides for an expedited review of drugs that appear to provide safe and effective therapy when no satisfactory alternative therapy exists, or offer significant improvement compared with marketed products.
The drug's safety and effectiveness were evaluated in a single clinical trial of 809 men with symptomatic castration-resistant prostate cancer that had metastasized to the bones but not to other organs. Patients were randomly assigned to receive Xofigo or a placebo plus best standard of care.
Results from a pre-planned interim analysis showed that patients receiving Xofigo lived a median of 14 months, compared with 11.2 months for patients receiving placebo.
In addition, at the interim analysis there was a delay in the time to first symptomatic skeletal event for patients treated with the drug compared with the group taking the placebo. An exploratory updated analysis conducted later in the trial confirmed Xofigo's ability to extend overall survival.
The most common side effects were nausea, diarrhea, vomiting, and swelling of the leg, ankle or foot. The most common abnormalities detected during blood testing were anemia, lymphocytopenia, leukopenia, thrombocytopenia, and neutropenia.
Also approved was an expanded use for Tarceva (erlotinib) as a first-line treatment for patients with non-small cell lung cancer that has metastasized and who have certain mutations in the EGFR gene.
The FDA also approved the cobas EGFR Mutation Test, a companion diagnostic for Tarceva that detects epidermal growth factor receptor gene mutations (present in approximately 10 percent of NSCLC).
The test is the first FDA-approved companion diagnostic that detects EGFR gene mutations. “Companion diagnostics play an important role in determining which therapies are the safest and most effective for a particular patient,” said Alberto Gutierrez, PhD, Director of the FDA's Office of In Vitro Diagnostics and Radiological Health.
“The approval of the cobas EGFR Mutation Test will allow physicians to identify non-small cell lung cancer patients who are candidates for receiving Tarceva as first-line therapy.”
The safety and effectiveness of the cobas EGFR Mutation Test was established with clinical data that showed, on average, that NSCLC patients with exon 19 deletions or exon 21 L858R substitution mutations (both EGFR mutations) lived without their disease progressing for 10.4 months after receiving Tarceva treatment, compared with 5.4 months for those who received a standard two-drug chemotherapy regimen.
Tumor samples from the clinical trial were used to validate the test's use in this group of patients.
The approval is Tarceva's fourth indication and the third use for lung cancer. The FDA approved Tarceva on April 16, 2010, for maintenance treatment of patients with locally advanced or metastatic NSCLC whose disease has not progressed after four cycles of platinum-based first-line chemotherapy.
Tarceva was originally approved in November 2004 for the treatment of patients with locally advanced or metastatic NSCLC after failure of at least one prior chemotherapy regimen.
Tarceva is marketed by Genentech, and the cobas EGFR Mutation Test is manufactured by Roche Molecular Systems.