Entry inhibitor

Vaginal gel blocks HIV but not enough to be scientific success

Candidate microbicide PRO 2000 cuts HIV transmission by 30 percent, falling just short of the one-third required to be deemed a success. But scientists say this trial offers proof that the concept of a vaginal gel to block HIV is possible. For the first time in over a decade of research, a vaginal gel called PRO 2000 has been show to cut HIV transmission by 30 percent. Principal investigator Professor Gita Ramjee described this as extremely hopeful at the simultaneous launch of the results in Durban and Montreal, Canada, yesterday (9 Feb). This is the first microbicide study in over a decade that shows promise. It suggests that we are on the right track and we will be able to develop a women-controlled product to prevent HIV in the future, said Ramjee, who heads HIV research at the Medical Research Council (MRC).

Radical AIDS drug set for launch in 2003

Roche Holding AG said on Wednesday it hoped to launch a revolutionary new AIDS drug in 2003, a drug that could save the lives of thousands of people who fail to respond to conventional therapy. T-20, being developed by the Swiss group and US biotech Trimeris, is the first of a new class of anti-HIV drugs called fusion inhibitors, which work by preventing the virus that causes AIDS from getting into the cells it attacks. William Burns, head of Roche's drug division, said Phase III trials on the product had just closed and a dossier seeking marketing approval would be filed with regulators in the second half of 2002, with launch likely in 2003. Roche Chairman Franz Humer said he expected T-20 to receive rapid approval, first in Europe and the United States, and later elsewhere around the world. Fighting a constantly mutating virus is one of the biggest challenges facing designers of AIDS drugs and T-20, which works by stopping HIV from fusing with human cells, represents a radical new approach. Current state-of-the-art combination therapies keep the virus at bay by attacking on three fronts at once, but some patients find that eventually they no longer work as the strain of HIV in their body evolves and outwits the drugs. Many HIV-infected patients are already clamouring for the new treatment - even though it must be given by injection rather than as a pill. (Source: Reuters, 15 August 2001)

Still No Vaccine, but Better Antiviral Drugs Are on the Way

In 1994, while searching for something that might work as a vaccine against HIV, Tom Matthews of Duke University, had stumbled upon a compound that blocked the AIDS virus from binding to, and thus infecting, healthy cells. It turns out that the compound Matthews identified doesn't work as an AIDS vaccine, but it may still make a very good AIDS drug. It belongs to a family of molecules known as entry inhibitors that, as the name suggests, prevent HIV's entry into healthy immune cells. While none are yet available in pharmacies, they are probably the most promising new class of anti-HIV drugs under review. It is already in the final stages of human testing with one compound and in the earliest phases of testing with a second. Entry inhibitors share an ability to thwart the virus outside the cell, before it has an opportunity to infect healthy immune cells. And that, some experts believe, may give them a better chance of dispatching HIV than the currently available antivirals, all of which work inside cells that have already been infected. This suggests that the new drugs might be effective at lower doses, making fusion inhibitors safer for the patient in the long run. Studies support this; so far, neither of its compounds seems to cause any of the serious toxic side effects associated with today's AIDS drugs, such as nausea, vomiting and abnormalities in fat metabolism.