If you're on your second or third (or more) antiretroviral combination, there is some good news. There are some new drugs for those of us who are developing resistance.

Aptivus

Aptivus® (tipranavir) is a new protease inhibitor that was approved by the FDA this past June. Aptivus has been available in expanded access for a while, but FDA approval means that it may be easier to get now for those who receive their drugs through the state drug assistance program (ADAP) or private insurance. Basically, your care provider should be able to prescribe it like any other antiretroviral such as Sustiva® (efavirenz) or Reyataz® (atazanavir). The difference, as far as treatment goes, is that Aptivus is FDA-approved for those who have developed resistance to other antiretrovirals. This means that if you're just starting therapy, Aptivus isn't one of the drugs that you would consider. The only exception might be in cases where someone is infected with multiple drug-resistant virus, which is rare. Bottom line: Aptivus is for salvage therapy. You won't be using it unless you've tried other options.

Aptivus needs to be boosted. If you are taking it, you'll also be taking Norvir® (ritonavir) to keep the level of drug up enough to fight the HIV. And of course, like other antiretrovirals, it should only be used in combination therapy. This can be sort of a "Catch 22" for anyone considering Aptivus. We know that adding one drug to a combination when you're resistant to the others already isn't the best way to go. What generally happens is that you will develop resistance to the new drug (in this case, Aptivus) pretty quickly, since it's the equivalent of monotherapy. And of course, you wouldn't consider Aptivus unless you have resistance to a fair number of antiretrovirals.

There are a couple of strategies that can help you get as much mileage as possible when using Aptivus. Resistance testing can help, because it can show what antiretrovirals may be effective as far as keeping HIV suppressed in a particular individual. And clinical trials that combined Aptivus with Fuzeon® (enfuvirtide, T-20) showed better results than other combinations, especially for people who have never taken Fuzeon before. Some people are reluctant to get involved with Fuzeon (it's only available as an injection), but the benefits of the combination certainly make it worth serious consideration, even if you don't like needles. If you're taking a regimen that includes Aptivus and your viral load begins a steady increase, you'll have a very limited range of options. There are other drugs in development now, but they are only available through clinical trials.

CCR5 Inhibitors

One area to watch if you are running out of treatment options is the new class of antiretrovirals that block HIV from attaching to CD4 cells. They work at a point very close to where Fuzeon does, but they target a protein called CCR5. Drugs from this class should work against HIV that is resistant to everything currently available, including Aptivus and Fuzeon. But if you're ready to toss your pillboxes, timers and the whole idea of adherence out the window because "they're coming up with new drugs," you might want to think again. First of all, you might end up where a lot of people who are considering Aptivus now are ... a great new drug, but nothing else to combine it with. It'll be very effective for a short period of time, but quick resistance is all but guaranteed. Second, this class of drugs is still not completely tested, so anything can happen.

GlaxoSmithKline recently issued a press release concerning their CCR5 entry inhibitor, aplaviroc. It's being tested in clinical trials, and there have been enough reports of hepatotoxicity (liver problems) for them to stop the involvement of anyone who is antiretroviral-naive. This may sound great if you're antiretroviral-experienced, since it means more opportunity for you to get into future trials that involve aplaviroc. The not-so-great part is that ... well, aplaviroc can be hard on your liver. If you have hepatitis C or anything else that might cause liver problems, you may not be able to tolerate this drug; at the very least, you will likely be excluded from clinical trials due to safety concerns while GlaxoSmithKline sorts everything out.

There are other CCR5 entry inhibitors in development. The pharmaceutical company Pfizer is developing one called maraviroc which has reached phase III clinical trials, the last stage before FDA approval. Vicriviroc, Schering-Plough's CCR5 inhibitor, is at about the same stage. If there are no problems, we may see them on the market in two to three years. If you want more information on antiretrovirals under development or have a question about treatment education, please call or stop by our Treatment Resource Center.