The notion of simple drug holidays -- taking a weekend or day off here and there -- is as much a bad idea today as it ever was. Repeated, short-term drug holidays will greatly increase the chances of developing resistance to anti-HIV drugs. In short, those who want to live long and healthy lives should avoid short little drug holidays.
So what is the scientific discussion about? Researchers are talking about structured interruptions of therapy. This means that the effort to stop treatment is part of a plan, with a goal in mind, not a matter of whimsy or personal convenience. Three general hypotheses will soon be tested. All call for interrupting therapy for a specific length of time, at a pre-planned point in time, in hopes of achieving a particular treatment goal.
In one hypothesis, researchers hope to determine if cycling people on and off therapy according to a set of rules might trigger a stronger immune response against HIV, and over time, make a person less dependent upon drugs to control viral load. A second hypothesis asks whether months-long interruptions in therapy might overcome drug resistance. The third hypothesis simply asks whether people suffering from serious side effects or severe drug weariness might give their bodies a rest from therapy without doing more harm than good. For now, there are no hard answers to these questions, only a few crumbs of intriguing data from small, short studies.
According to the manufacturer, the program will serve only a few hundred people in the US because of limited drug supplies. First priority will be given to people who have fewer than 50 CD4+ cells and/or an active opportunistic infection. Second priority, supply permitting, will be for people with CD4+ counts between 50 and 100. Third priority, supply permitting, will be for people with CD4+ counts between 100 and 200. A much larger expanded access program will extend availability of the drug to more people in early 2000. Because of the limited size of the program beginning in September, it's important to apply as soon as possible. Those interested should call Project Inform's National HIV/AIDS Treatment Hotline at 1-800-822-7422 for information.
ABT-378 is also available through clinical studies. Abbott reports many slots are still available, primarily for people who have failed only a single protease inhibitor and who have not yet used a non-nucleoside reverse transcriptase inhibitor (delavirdine, efavirenz or nevirapine).
Another motivation is to simplify drug dosing. Sometimes, combining two protease inhibitors may increase the blood levels of one or both drugs, thus reducing the number of pills needed, the number of times a day drugs are taken, or changing the associated food restrictions associated. This only works well with certain combinations, such as ritonavir plus saquinavir or indinavir. Combining some drugs often offers no advantages: it simply increases the number of pills a person must take. While using novel combinations to simplify regimens is an important goal for some people, limited data are available on how to best do this. Patients and doctors need to be well informed, lest they do more harm than good.
Another motivation for experimental combinations is to increase the overall potency of the regimen. The effect of combining the "right" drugs can be much greater than what would be expected from simply adding another drug. Some people seeking the strongest possible anti-HIV regimen may use all three classes of drugs. This approach runs the potential risk of using up options too quickly. If a person experiences viral breakthrough while on a regimen that includes all classes of drugs, s/he could develop resistance to any and all classes of drugs, thus greatly limiting future options.
For more detailed information on anti-HIV drug interactions, contact Project Inform's toll-free National HIV/AIDS Treatment Hotline at 1-800-822-7422 and request the Drug Interactions Fact Sheet.
|Amprenavir APV||No data available3||EFV 600mg, 1x; APV 1,200mg, 3x8 (no clinical data)||Standard Doses||Standard Doses1||No data available2||APV 1,200mg, 2x; RTV 200mg, 2x4 (no clinical data)||Standard Doses|
|Delavirdine DLV||No data available3||No data available||IDV 600mg, 3x; DLV 400mg, 3x||Standard Doses||No data available||Standard Doses5||Standard Doses|
|Efavirenz EFV||EFV 600mg, 1x; APV 1,200mg, 3x8 (no clinical data)||No data available||IDV 1,000mg, 3x; EFV 600mg, 1x||Standard Doses||No data available||Standard Doses||Use with Caution6|
|Indinavir IDV||Standard Doses||IDV 600mg, 3x; DLV 400mg, 3x||IDV 1,000mg, 3x; EFV 600mg, 1x||Standard Doses||IDV 800-1,000mg, 3x; NVP 200mg, 2x||RTV 100mg or 400mg, 2x; IDV 400 or 800mg, 2x7||Standard Doses|
|Nelfinavir NFV||Standard Doses1||Standard Doses||Standard Doses||Standard Doses||Standard Doses||RTV 400mg, 2x; NFV 750mg, 2x||NFV 750mg, 3x; SQV 600 or 800mg, 3x|
|Nevirapine NVP||No data available2||No data available||No data available||IDV 800-1,000mg, 3x; NVP 200mg, 2x||Standard Doses||Standard Doses||Standard Doses|
|Ritonavir RTV||APV 1,200mg, 2x; RTV 200mg, 2x4 (no clinical data)||Standard Doses5||Standard Doses||RTV 100mg or 400mg, 2x; IDV 400 or 800mg, 2x7||RTV 400mg, 2x; NFV 750mg, 2x||Standard Doses||RTV 400mg, 2x; SQV 400mg, 2x|
|Saquinavir SQV||Standard Doses||Standard Doses||Use with Caution6||Standard Doses||NFV 750mg, 3x; SQV 600 or 800mg, 3x||Standard Doses||RTV 400mg, 2x; SQV 400mg, 2x|
|1x = one time daily. 2x = two times daily. 3x = three times daily.|