New Treatment for AIDS-Linked Illness Reported
Researchers at San Francisco General Hospital believe that they have developed a treatment for one of the most serious ailments afflicting AIDS patients that avoids the severe side effects of other therapies.
The treatment involves an aerosol spray of an antibiotic used to treat pneumocystis carinii pneumonia, which is the first sign of the disease in about three-fifths of all AIDS patients.
Antibiotics injected directly into the bloodstream have long been used to treat the pneumonia in AIDS patients but are often accompanied by adverse reactions, including low white blood cell counts, low blood pressure, liver damage and rashes. The side effects are so severe, that about half the patients who receive the antibiotics intravenously have to change medicines or stop their treatments entirely. The complications lengthen hospital stays and increase medical bills by thousands of dollars.
In a study to be published Saturday in The Lancet, a British medical journal, Dr. A. Bruce Montgomery and colleagues at San Francisco General report that 13 of 15 patients were successfully treated with three weeks of aerosol therapy, a response rate comparable to that with intravenous medications but without the adverse side effects. Coughing was the only adverse reaction detected.
Fatal Illness
If the San Francisco findings are confirmed in larger studies, the aerosol therapy may dramatically influence the care of thousands of AIDS patients because 65% of all AIDS patients develop pneumocystis pneumonia at least once during the course of their ultimately fatal illness. Although 85% to 90% of AIDS patients survive a first attack of pneumocystis pneumonia, more than half of the patients who develop this pneumonia die within one year.
“This new treatment allows AIDS patients to complete their pneumocystis therapy without severe adverse reactions,” Montgomery, an assistant professor of medicine at the University of California, San Francisco, School of Medicine, said in an interview.
He added that it also may lead to substantial cost savings by shortening hospital stays and by “making outpatient therapy of the disease possible.”
Already, the new therapy is being “widely used” by many acquired immune deficiency syndrome specialists in Los Angeles, San Francisco and New York City to try to prevent the development of pneumonia in AIDS patients, according to Dr. Michael S. Gottlieb, an AIDS specialist in private practice in Santa Monica.
“Our own experience has been very favorable to date,” he said. “Adverse reactions have been much less frequent than with other regimens.”
Serious Complications
But despite the promising initial results, Montgomery cautioned that the breathing therapy advance was “not going to cure AIDS or make the disease go away.” Until further data is available, he said pneumocystis patients should continue to receive the standard intravenous medications unless they develop serious complications.
“This may someday be first-line therapy. But I don’t recommend it as first-line therapy because I haven’t proven it yet,” he said.
The research began in the fall of 1985 after Montgomery had seen many patients with the pneumonia develop severe side effects from the intravenous antibiotics.
Many AIDS physicians accepted the toxicity problem as an inevitable consequence of treating these patients. But Montgomery and other researchers decided to see if they could solve it.
The researchers knew that the pneumocystis infection was usually confined to the superficial layers of the air sacs of the lungs, unlike other infections that often penetrate the lungs and invade the bloodstream. So instead of giving patients intravenous doses of the antibiotic pentamidine, they decided to have patients breathe a fine mist of the antibiotic directly into their lungs.
Once a Day
Drawing on promising experiments in rats, Montgomery and his colleagues treated 15 AIDS pneumonia patients at San Francisco General Hospital earlier this year with 20 minutes of inhaled pentamidine therapy once a day.
The experimental therapy, which costs about $200 a treatment, is given by dissolving pentamidine powder in sterile water, according to the medical journal report.
The patient then breathes in the medicine through a specially designed inhalation device called a nebulizer. The nebulizer disperses the medication into a fine mist while filtering out large particles that might trigger severe coughing spells.
In the preliminary San Francisco study, one pneumocystis patient, who also had tuberculosis, died. A second patient, who survived, was switched to another intravenous antibiotic 20 hours after his first dose of inhaled pentamidine, for what the researchers called “unrelated” reasons. The other patients were successfully treated without side effects.
The two leading medicines for pneumocystis, pentamidine and trimethoprim-sulfamethoxazole, are usually administered through the veins. But when pentamidine is given through the vein, only 3% to 4% of the dose gets to the lungs; the rest is distributed throughout the body and can cause severe toxicities.
No Advantage
By comparison, when pentamidine is inhaled directly into the lungs, 99% of the drug remains in the lungs to fight the pneumonia, Montgomery said. There is no advantage to inhaling the other medication, trimethoprim-sulfamethoxazole, because it rapidly enters the bloodstream and can still cause side effects.
