The Washington Blade - December 15, 2000
A study from Rome of 1,251 people with HIV found they
experienced "similar efficacy" whether they were taking the
protease inhibitor ritonavir or indinavir in combination with
The study was reported in the Nov. 20 issue of AIDS Research
and Human Retroviruses.
The researchers, led by Stefano Vella, president of the
International AIDS Society, did notice that viral loads seemed
to decline more with indinavir. They also noted that patients
on ritonavir were more likely to experience a significant
negative side effect.
But the two treatments, noted the report, "were not different
in terms of number of definitive discontinuations because of
treatment failure" and the study result "suggests similar
efficacy of the two treatments in patients who can tolerate
Lab companies defining resistance test 'cutoffs'
Two companies providing "resistance testing," which helps
doctors determine what anti-HIV drugs their patients are most
likely to respond to, announced in the past few weeks that they
have defined important and previously unknown "cutoff levels"
on the effectiveness of several drugs.
One company, ViroLogic, reported that the increasingly popular
protease inhibitor ABT-378 (lopinavir, marketed by Abbott as
Kaletra) loses its clinical effectiveness when a phenotype
resistance test shows the virus has mutated to a 10-fold
reduction of its susceptibility to the drug. With the Glaxo
Wellcome nucleoside analog abacavir (marketed as Ziagen), said
ViroLogic, this "cutoff" level is 4.5-fold.
At an AIDS conference in Scotland in October, the British lab
company Virco reported that the nucleoside analogs ddI and d4T
have "the lowest frequency of resistance," that ddC had
"infrequent resistance," and that AZT and 3TC "appeared most
frequently" to develop resistance.
Generally, noted Virco, nucleoside analogs have significantly
less benefit at a cutoff level of 3 to 4.5-fold decreased
susceptibility; protease inhibitors have a cutoff at 2.5 to
4-fold; and non-nucleoside analogs have a cutoff at 6 to
Both companies are continuing their work in defining the
specific cutoff for each drug, but David Ho of New York's Aaron
Diamond AIDS Research Center said the definition of these
cutoff levels is an "important achievement" that will help
doctors make "more informed" decisions about drug choices.
In brief ...
NONOXYNOL-9 REMOVED FROM "WET": The manufacturer of a popular
brand of lubricant announced last month that it has removed the
spermicide nonoxynol-9 from its products. Trigg Laboratories,
the maker of WET products, said the company's move was in
response to a warning issued by the U.S. Centers for Disease
Control and Prevention in August. The warning came following a
report at the International Conference on AIDS that women using
spermicides with nonoxynol-9 became infected with HIV at about
a 50 percent higher rate than women using a spermicide without
the substance. According to the CDC notice, "anyone currently
using N-9 as a microbicide to protect themselves from HIV
transmission during anal intercourse should be informed of the
ineffectiveness of this agent and warned of the potential risk
of this practice. ... If given the choice, condoms without N-9
may be a better option for HIV prevention."
TRIPLE-DRUG PILL APPROVED: The U.S. Food and Drug
Administration approved an anti-HIV pill Nov. 16 that combines
three nucleoside analogs. The pill - called Trizivir - combines
three drugs produced by Glaxo Wellcome: AZT-3TC-abacavir. With
increasing emphasis on the use of a combination of drugs to
suppress the virus, the combination, which is taken twice a
day, is expected to ease the pill-taking burden for at least
some patients. The FDA also recently approved a new "coated"
version of Bristol-Myers' nucleoside analog ddI (marketed as
Videx). The new form, Videx EC, includes an enteric coat that
prevents the drug from being released into the system until it
hits the small intestine where it is absorbed. With the
standard version of ddI, patients must take antacids
simultaneously to prevent the pill from being dissolved too
quickly. The new version also relieves the patient of the need
to chew the tablet, which has a taste that many find
NON-NUKE WARNING STRENGTHENED: The FDA "strengthened" its
warning last month about the risk of life-threatening liver
toxicities associated with the use of the non-nucleoside analog
nevirapine, especially in the first three months of use. The
drug is marketed as Viramune by the Boehringer Ingelheim/Roxane
Laboratories. The early warning signs of trouble, noted the
FDA, include fatigue, malaise, anorexia, and nausea, followed
by jaundice and an enlarged liver. Patients taking nevirapine
who experience these symptoms are advised to see their doctors