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Editor’s Note: This is the fourth in a series of articles we are running on the major manufacturers of HIV medications. The articles do not focus on the companies themselves as much as the life-saving drugs they manufacture. The company featured this time around is Gilead Sciences. Gilead is a relatively new biotech company, but it already produces some of the most popular medicines in the HIV market.

We had the opportunity to talk with Norbert Bischofberger, Ph.D., Gilead Sciences’ Executive Vice President for Research and Development, about the company’s arsenal of HIV drugs as well as its plans for future drug development. We began by reviewing Gilead’s current drugs in chronological order, starting with their first: Viread.

VIREAD (tenofovir)

Viread was approved by the US Food and Drug Administration (FDA) in 2001, and it was an instant success. Soon after its release, Viread won the coveted “preferred” designation in United States Department of Health and Human Services (DHHS) treatment guidelines. The dose is one 300 mg pill, taken just once-a-day, with or without food.

“Gilead’s theme has always been simplification of therapy,” Dr. Bischofberger notes. “We have chosen not to pursue compounds that have a short half-life and therefore would have to be taken two or three times a day. Our goal has always been to come up with once-daily therapies. When Viread was approved there were only two other once-daily HIV medications, so it was a step forward for HIV and AIDS patients in terms of dosing convenience.”

EMTRIVA (emtricitabine)

Gilead’s second HIV drug, Emtriva, was approved by the FDA in 2003. Emtriva’s dose is also just one capsule a day, and, like Viread, it was readily accepted by the HIV community. It also won the “preferred” designation in the DHHS treatment guidelines. Emtriva is frequently compared to Epivir – which is not a bad thing, since Epivir is a very highly-regarded drug.

“Once we had two effective once-daily HIV drugs with long-term tolerability, the obvious thing to do – and our intention all along – was to co-formulate them,” Dr. Bischofberger says. “We did, and the result was Truvada.”

TRUVADA (emtricitabine/tenofovir)

Truvada was approved by the FDA in August, 2004. Combination drugs are tremendously popular among HIV and AIDS patients, and Truvada is no exception. All HIV therapies require at least three different drugs. To be able to take two-thirds of your drug regimen in one pill, taken once-a-day, is fantastic.

But Gilead didn’t stop there. Shortly after Truvada was released, the combination of Truvada and Sustiva (efavirenz) became one of the most popular regimens in the HIV market. Sustiva also can be taken once-a-day, so for the first time it was possible to control HIV with just two pills, usually taken before bedtime.

Why not combine the two – Truvada and Sustiva – into the ultimate all-in-one single pill regimen? The answer: because Sustiva is made by a rival company, Bristol-Myers Squibb.

Gilead didn’t let that stop them. In an historic cooperative agreement that is to the credit of both companies, Gilead and BMS agreed in 2004 to jointly develop and market a combination of Truvada and Sustiva. The result was:

ATRIPLA (efavirenz/emtricitabine/tenofivir)

Atripla, which has just been approved by the FDA, is the first-ever complete HIV regimen that comes in a single pill, taken just once-a-day.

Ten years ago, the first effective treatments for HIV often required you to take as many as 30 pills a day, often in five different dosing intervals. To boil all that down to just one pill, taken once-a-day, is an astonishing achievement that cannot be overstated.

“With Atripla, BMS and Gilead have set an example for the industry,” Dr. Bischofberger says. “Reducing a three-drug HIV regimen to a single pill increases patient convenience, reduces co-pays, and makes it easier for the physician to prescribe. It makes so much sense that I think you’ll see more similar combinations in the future. Gilead may do more.”

WHAT'S NEXT?

“We’ve made incredible progress in the last ten years, and I’m optimistic that we’ll make equal progress in the next ten years,” Dr. Bischofberger says. “Having better treatments – easier to take and better tolerated – hopefully will encourage more people to get treatment. That could lead to reductions in transmission. In a generation or two, we may see much smaller infection rates than we have now – at least in the United States and Western Europe. In Africa, we still have a huge problem on our hands. Unless more is done at the political level, I don’t see how we can bring that under control.”

“In terms of drug development, we’re working hard on developing an integrase inhibitor. All but one of the current HIV drugs are aimed at just two targets: reverse transcriptase and protease. It would be great to have a drug that attacks a new target and could be used with any existing drug. Both Gilead and Merck have integrase inhibitors in advanced clinical development. So far, they seem to be potent, well-tolerated, and safe. If one gets to market, it will give a huge number of patients a new option.”

Copyright 2008, Positive Health Publications, Inc.

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