New Class of Drugs Shows Promise for Resistant HIV Strains
The mainstays of therapy for HIV infection have been two classes of drugs: reverse transcriptase inhibitors and protease inhibitors. Each targets a different enzyme required by HIV for proliferation, and combinations of drugs from the two classes have been quite successful in reducing viral proliferation in the majority of patients.
But some patients treated with these drugs no longer respond to them because the virus strains they carry have become resistant, leading to a rebound of virus proliferation and, in many cases, to full-blown AIDS.
Such patients may soon have an alternative, a new class of drugs that works by a completely different mechanism, researchers said Thursday at the sixth Conference on Retroviruses and Opportunistic Infections in Chicago. The new drugs are called fusion inhibitors and, in early trials, they have shown that they can block the entry of HIV into its target cells, a key step in viral reproduction.
One promising fusion inhibitor is T-20, developed by Trimeris Inc. of Durham, N.C.
Dr. Joseph Eron of the University of North Carolina at Chapel Hill reported on 78 HIV-positive patients who had been treated with an average of nine AIDS drugs and who still had high virus levels in their blood.
Eron found that continuous infusion of T-20 or twice daily injections significantly lowered the amount of virus in the patients’ blood, often to the point of being undetectable. He noted that the results were particularly impressive because “the population enrolled in this clinical trial is extremely difficult to treat.”
The team is now planning larger studies.
Lab-Grown Neurons May Help After Stroke
Transplanting neurons grown in the laboratory into the brains of stroke patients may help some regain motor and speech skills that otherwise would have been lost forever, Pennsylvania researchers reported Thursday at the American Heart Assn.’s annual International Conference on Stroke and Cerebral Circulation in Nashville, Tenn.
Of the seven patients treated with the cultured brain cells, all were able to leave the hospital within 24 hours, and three have noticed small improvements in motor skills, said Dr. Douglas Kondziolka of the University of Pittsburgh Medical Center.
The patient who received the first transplant seven months ago--a 62-year-old woman who had a major stroke in fall 1997--has had slight improvements in speech, Kondziolka said.
These first studies, Kondziolka said, are designed primarily to demonstrate the safety of the process. Future trials will use larger numbers of cells and target other brain areas as well.
Study Casts Doubt on Benefits of Coumarin
An experimental drug sometimes recommended to relieve painful swelling after breast cancer surgery is ineffective and may cause liver damage, according to a study in Thursday’s New England Journal of Medicine. Dr. Charles Loprinzi and his colleagues at the Mayo Clinic studied 140 women who each had surgery to remove a cancerous breast and were given the drug coumarin, and found no benefit from the drug.
Coumarin is an easily made chemical that is sold in Mexico and can be ordered by mail, but is not licensed as a drug in the United States. Nonetheless, many clinics that treat breast cancer patients quietly recommended it after a 1993 study found it could reduce the painful swelling, known as lymphedema, that can follow breast surgery.
Breast cancer strikes 175,000 U.S. women annually. Up to 60% of women who have a cancerous breast removed, and 30% who have less radical breast surgery, get some type of painful swelling in the arm closest to the surgery site.
Loprinzi said the earlier study may have given misleading results because it involved only 31 women. The team was surprised to find that blood tests showed evidence of liver damage in 6% of patients using coumarin. Previous studies showed liver problems in less than 1% of cases.
Use of Antibiotics May Lower Heart Attack Risk
Use of antibiotics such as tetracycline appears to reduce the risk of heart attack, according to a study of medical records of more than 16,000 patients in Britain conducted by researchers at the Boston University Medical Center.
But Dr. Hershel Jick and his colleagues warned in Wednesday’s Journal of the American Medical Assn. that larger studies are needed to confirm whether there is a link between use of antibiotics and preventing heart attacks. Other research also has indicated that antibiotics may help prevent heart disease.
The Boston University Medical Center researchers said their study may be the first to look at the effects of antibiotics on preventing first heart attacks in previously healthy patients.
The researchers drew from the U.K.’s General Practice Research Database, a collection of computerized medical records.
In their research, they selected 3,315 patients who had suffered heart attacks and compared their records to those of 13,139 patients who had not suffered heart attacks.
Their findings indicate patients who took tetracycline, a common generic antibiotic, were less likely to have heart attacks. The same was true for those who took quinolones, a class of antibiotics that includes Bayer’s Cipro and Johnson & Johnson’s Floxin.
The Boston University study indicates that penicillin, macrolides and cephalosporins showed no significant connection to reducing the risk of heart attack. Macrolides include Abbott Laboratories’ Biaxin and Pfizer Inc.’s Zithromax.
