AZT Remains a Mainstay in AIDS Fight
AZT is not the miracle AIDS patients had once hoped for, but in the last five years, the drug has become a mainstay in treating the HIV virus, researchers said.
AZT changed the AIDS landscape, giving scientists their first hope that the disease could be treated. But it cannot single-handedly combat the virus, said the authors of a retrospective look at AZT in the Annals of Internal Medicine.
“There was always the hope that it could silence the virus,” said co-author Dr. Gavin McLeod of the New England Deaconess Hospital. “But in reality, knowing that it did not inhibit the virus 100%, we’re not surprised it didn’t.”
But AZT, scientists recently reported, may also delay the onset of AIDS in people infected with HIV but without symptoms of AIDS.
AZT, or zidovudine, is the only one of three HIV antiviral drugs approved by the Food and Drug Administration. The other two are known as ddC and ddI; ddC is used in combination with AZT, while ddI is given when the patient can no longer tolerate AZT.
The first hints of AZT’s ability to fight the AIDS virus came in 1985 from its makers at Burroughs Wellcome Co.
Two years later, after researchers showed it could prolong the lives of AIDS patients, AZT became the first drug to win federal approval to treat the virus.
“To know that eight years later that there are people alive that otherwise wouldn’t be is a very positive experience,” said Dr. Sandra Nusinoff-Lehrman, one of the Burroughs Wellcome scientists who developed AZT. “It substantially changed the course of the disease.”
In 1987, Dr. Margaret Fischl and colleagues at the University of Miami showed the effectiveness of AZT.
“We were so lucky to find that early success,” said Dr. Judith Feinberg of Johns Hopkins University, who helped set up the first federally sponsored clinical trials of AZT. “AZT turned the world upside down and rewrote the rules of how we would proceed.”
Still, some say it’s time to move on to developing other treatments.
AZT “works some of the time for some of the people,” said David Gold of the Gay Men’s Health Crisis. “It is not the compound that has made HIV infection a chronic, manageable disease, and that’s a great disappointment.”
Attention should focus on drugs that work differently against the virus and boost the immune system, Gold said.
Stanford University’s Dr. Thomas Merigan, who investigates AZT alternatives, agreed that HIV needs new types of intervention. But, he added, researchers and patients should not abandon AZT.
It will not be as easy to develop as successful a new generation of AIDS therapies, Feinberg said.
“Until there are several drugs with several different actions, AZT will continue to be essential. New drugs will have to be blockbusters to eclipse AZT,” she said.
In the Annals’ review, McLeod and co-author Dr. Scott Hammer said that the quick FDA approval of AZT enabled doctors to learn much about AZT once it was in use.
The main lesson learned was that the drug’s side effects--nausea, muscle pain and anemia--are less frequent at the lower doses now used, and that those problems can be overcome.
“Although much has been learned . . . during the past five years, many areas of promise and uncertainty remain that need to be further explored,” they said. “We hope to move well beyond this first but important step in the treatment of HIV-infected persons in the next five years.”
AZT, marketed as Retrovir by Burroughs Wellcome, had worldwide sales of $315 million in the fiscal year that ended Aug. 31, 1991, the last figures available, said company spokeswoman Sharon Bickus.
