WASHINGTON -- The Food and Drug Administration granted final approval Friday for prescription sale of AZT, the first drug known to be effective in treating AIDS patients.
The drug, whose full name is azidothymidine, will be marketed by Burroughs Wellcome Co. of Research Triangle Park, N.C., under the trade name Retrovir.
Because supplies of the drug are limited, it will initially be reserved for patients with AIDS and AIDS-related complex who have the most severely weakened immunity to opportunistic infections or who have had a history of a type of pneumonia called Pneumocystis carinii pneumonia (PCP).
Assistant Secretary of Health Robert Windom, announcing the historic approval, said, 'Today's action means that significant medical relief will be available to thousands of those afflicted with this dreaded disease.'
Windom said that clinical data were insufficient to approve the use of Retrovir for all AIDS-associated conditions but said most of the approximately 14,000 AIDS patients in the United States expected to qualify for the drug, 'particularly those who have had a serious opportunistic infection associated with AIDS.'
There have been 32,825 reported cases of AIDS, 19,021 of them resulting in death, according to the Centers for Disease Control.
'Certain patients with advanced ARC, a condition that frequently precedes and develops into AIDS within a short period of time, have also been shown to benefit from therapy with Retrovir,' Windom said, adding that two to three times as many Americans may suffer from advanced ARC as suffer from AIDS.
'Today's approval marks an important step, but by no means a final victory,' Windom said. 'Retrovir is not a cure for AIDS, but it has demonstrated ability to improve the short-term survival of AIDS patients with recently diagnosed PCP and certain patients with advanced AIDS-related complex.'
Burroughs Wellcome spokeswoman Kathy Bartlett said enough AZT will be available for at least 15,000 patients by April 1 and 30,000 by the end of this year.
But by conservative estimates, at least 41,400 patients could qualify for AZT today.
Ed Collins, head of drug information services at Burroughs Wellcome, said patients who meet the prescription criteria established by the FDA would be signed up on a first-come, first-serve basis.
Doctors wishing to prescribe the drug will have to apply to the company for permission, sending details of their patient's history. The company will provide an uninterrupted supply of the drug to patients once they start on AZT.
'If there is not enough,' Collins said, 'new applications will be put in a queue and contacted in order.'
The government began making AZT available free of charge in September to patients with these conditions, even though the drug had undergone only limitedtesting. Results were so good scientists felt it would be unethical to withhold AZT.
A panel of experts recommended in January the FDA approve AZT. Since then, more than 4,500 AIDS U.S. patients have received AZT free of charge. The drug was recently approved for marketing in Britain.
Windom noted that under a special priority review procedure, the FDA had reviewed and approved Retrovir in less than four months -- one of the quickest approval actions on record. Developed in 1964 by Dr. Jerome Horowitz of the Michigan Cancer Foundation as an anti-cancer drug, AZT was found to prevent reproduction of the AIDS virus in cells.
Burroughs Wellcome said testing of the drug's efficacy began in February 1986, with 137 patients receiving a dummy drug and 145 getting AZT. There were 16 deaths among the 137 patients receiving the dummy and only one death among patients receiving AZT. Some symptoms, such as severe weight loss, fungal infections and neurological problems were relieved by the drug.
Since then, new studies have begun to test the drug on patients with Kaposi's sarcoma, a soft-tissue cancer characteristic of AIDS, and young people with AIDS.
Eighty-four percent of patients enrolled in the first efficacy study were still alive as of March 10, T.E. Haigler Jr., Burroughs Wellcome president and chief executive officer, said in a congressional hearing.
The drug is known to have side effects, incuding anemia and suppression of the bone marrow in some patients. The long-term consequences of taking the drug are unknown.
Retrovir is expected to cost $188 wholesale for 100 tablets of 100 milligrams each. Cost to the patient could run between $7,000 and $10,000 or more annually.