PARIS: Fresh data put forward at the Paris AIDS conference on Tuesday confirmed a surge of optimism surrounding a new drug aimed at blocking the human immunodeficiency virus (HIV) from infiltrating immune cells.
Fuzeon, the commercial name for the drug, is the first of a revolutionary class of drugs, called fusion inhibitors, that break starkly with the traditional approach for tackling the stealthy AIDS virus.
The prototype drug was unveiled last year in a frenzy of interest. Trials with 1,000 volunteers suggested that, within 24 weeks, it could literally pull back some people from the jaws of death, suppressing sky-high viral levels in the blood and boosting the count of vital CD4 immune cells.
Evidence presented on Tuesday from longer-term studies, in which Fuzeon was assessed over 48 weeks and used in conjunction with one or several classic HIV drugs, confirmed those benefits and proved there were negligible side-effects, researchers said.
That is good news: for many people taking conventional antiretroviral drugs, viral loads typically start to creep up again after a few months, the CD4 count begins to edge down and toxic side-effects, or early signs of resistance, start to show.
“Patients maintained their level of response three times longer than with typical antiretrovirals,” said David Reddy, in charge of HIV strategy at Roche, the Swiss pharmaceutical giant which is behind Fuzeon, along with a small research company, Trimeris Inc. of the United States.
Fuzeon, whose chemical name is enfuvirtide and was codenamed T-20, was approved by the United States and the European Union (EU) earlier this year.
It is the first big pharmaceutical weapon against AIDS since the advent in 1995 of highly active antiretroviral treatment (HAART) — the “cocktail” of drugs that, for those in the rich world, has transformed HIV from a killer to a manageable disease.
Fuzeon “is a breakthrough drug... a very exciting drug,” Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases (NIAID), a renowned figure in the AIDS, said on Monday.
“It is the first drug to aim at a new target.”
Fuzeon is designed as salvage therapy — a last resort for people who are either resistant to classic HIV drugs or cannot tolerate its side-effects. But it has drawbacks.
It is a highly complex molecule that, at moment, can only be delivered by injections beneath the skin, rather than by pills. The patient uses a simple insulin-style injector to do this, which is uncomfortable and can lead to occasional bacterial infections of the skin.
In addition, it is extremely expensive: 20,000 dollars a year, a price that reflects an awesomely complex, seven-month manufacturing process.
That cost, and the need to keep the drug refrigerated, will put it out of reach of poor countries, where the overwhelming majority of the 40 million people with HIV live.
HIV was first identified as the cause of AIDS in 1983, yet there is still no cure or vaccine for it. Fuzeon is not a cure, and it is likely to encounter resistance problems, just as other drugs before it have.
HAART comprises protease inhibitors, which target enzymes that help the human immunodeficieny virus (HIV) to reproduce after it enters the CD4 immune cell. Fusion inhibitors, also called entry inhibitors, aim to stop HIV from entering the CD4 cell in the first place.
The goal is to block the way the virus docks onto the cell surface with its gp120 protein, which is followed by a harpoon-like manoeuvre by a second protein, gp41, that penetrates the cell membrane. Once the viral and host cell membranes have fused, the virus is able to spew its genetic material into the host cell, thereby infecting it and opening the way to its own reproduction.—AFP