Leukemia Drug Pulled from U.S. Market
At the FDA’s request, Pfizer Inc. voluntarily withdrew the drug gemtuzumab ozogamicin (Mylotarg) from the U.S. market on June 21. The monoclonal antibody was approved in 2000 to treat patients age 60 and older with recurrent acute myeloblastic leukemia (AML) who were not considered candidates for other chemotherapy. Results from a phase III clinical trial begun in 2004 now show an increased risk of death in patients who received gemtuzumab ozogamicin compared with patients who received standard chemotherapy. The drug has also been associated with veno-occlusive disease, a potentially fatal condition in which small veins in the liver become blocked.
“Mylotarg was granted an accelerated approval to allow patient access to what was believed to be a promising new treatment for a devastating form of cancer,” said Dr. Richard Pazdur, director of the Office of Oncology Drug Products in the FDA’s Center for Drug Evaluation and Research. “However, a confirmatory clinical trial and years of postmarketing experience with the product have not shown evidence of clinical benefit in patients with AML.”
New Treatment Approved for Advanced Prostate Cancer that Resists Docetaxel
The FDA has approved a new drug, cabazitaxel (Jevtana), for patients with advanced, hormone-refractory prostate cancer that has progressed during or after treatment with docetaxel (Taxotere). The drug is approved for use in combination with prednisone, a steroid that is often used in this setting. The approval on June 18 was granted under the FDA’s priority review program, which shortens the agency’s analysis to 6 months for drugs that may offer major advances in treatment or provide a treatment when no adequate therapy exists; in fact, this review was accomplished in 11 weeks, said the FDA’s Dr. Richard Pazdur.
The approval was based on the results of the international TROPIC (Treatment of Hormone-Refractory Metastatic Prostate Cancer) trial, which were presented earlier this year at ASCO’s Genitourinary Cancers Symposium. The study compared cabazitaxel head-to-head with mitoxantrone (both used in combination with prednisone) and showed about a 30-percent reduction in the risk of death.
Nilotinib Approved to Treat Rare Form of Chronic Myeloid Leukemia
The FDA has approved the drug nilotinib (Tasigna) to treat newly diagnosed patients with a rare blood cancer, Philadelphia chromosome-positive, chronic-phase chronic myeloid leukemia. Nilotinib was originally approved in 2007 to treat patients whose disease had progressed or who could not tolerate other therapies, such as imatinib.
“It is important for companies to continue developing oncology drugs for earlier stages of [a] disease once they have demonstrated clinical effectiveness in resistant forms of [the] cancer…an approach [that] has the potential to increase the availability of an effective treatment to more patients,” said Dr. Richard Pazdur of the FDA.
The agency took less than 6 months to make this decision under their accelerated approval program, evaluating the safety and effectiveness of nilotinib in a trial using a surrogate endpoint to predict clinical benefit, in this case the number of CML cancer cells in the blood stream. After 1 year of treatment, 44 percent of patients who received nilotinib experienced this “major molecular response” compared with 22 percent of those who received imatinib.