ROCKVILLE, Md--After hours of heated debate, the FDA's Oncologic Drugs Advisory Committee (ODAC) decided there was sufficient evidence of efficacy to recommend approval of DOX-SL (pegylated liposomal doxorubicin(Drug information on doxorubicin)) for the treatment of AIDS-related Kaposi's sarcoma (KS) in patients who have failed first-line treatment or who cannot tolerate other treatment. The potential benefits of the drug generally outweigh the risks, the committee said.
However, their recommendation to the FDA was for accelerated approval of the drug. A recommendation for unconditional approval was unanimously voted down, due to concerns about possible protocol and safety violations and difficulties in measuring improvements in the studies.
Under the accelerated approval status, the drug's sponsor, Liposome Technology, Inc. (LTI), of Menlo Park, Calif, will be required to collect additional pertinent data to carry out appropriate postmarketing studies.
'Not Just Another Analog'
I. Craig Henderson, MD, chief of medical oncology, University of California, San Francisco, and a director of LTI, referred to DOX-SL as a "new drug" rather than an analog of doxorubicin. He said that liposomes are generally versatile drug carriers, but they may be limited in their ability to reach target cells. However, DOX-SL, a liposome packed with doxorubicin, has proved to be highly stable, with a relatively long half-life and clearance rate.
Because of its long plasma residence time, DOX-SL tends to preferentially enter tissues with compromised blood vessels (such as soft-tissue tumors) and therefore provides good therapeutic effect, Dr. Henderson said. In a regimen of 20 mg/m² every 3 weeks, DOX-SL has demonstrated the ability to deliver and maintain therapeutic doses of doxorubicin to KS lesions.