The AIDS Drug Pipeline
Keeping HIV Out continued...
The downside: T-20 has to be taken by injection. This inconvenience means that the drug probably will be saved for people to use only after their first- and second-line anti-HIV drugs fail.
However, T-20 might be a great "morning-after" drug for people recently exposed to the AIDS virus. Current anti-HIV drugs fight the virus only after it's penetrated deep inside the body. T-20 keeps the virus from getting a foothold in the first place.
There are several other entry inhibitors in various stages of development.
Nucleoside RT inhibitors -- NRTIs or "nukes" in the lingo of HIV research -- have been the mainstay of AIDS therapy since AZT came out in 1987. The "RT" in NRTI is the target -- it's the tool the virus uses to change its RNA genetic code into the DNA code that takes over a cell. Seven now are approved, including Viread, a close relative to the NRTI family.
What's new in nukes:
- DPC 817 kills HIV that's already developed resistance to AZT (Retrovir) and lamivudine. It's in early human trials.
- BCH-13520 kills HIV resistant to other nukes. In the test tube, HIV has a hard time getting around this drug. Animal tests are underway.
- GS 7340 is a form of Viread designed to work better as an oral drug. It looks good in animal studies.
Non-nucleoside RT inhibitors -- NNRTIs or non-nukes -- attack the same target as nukes, but in a different way. One of these drugs, Sustiva, is among the most potent anti-HIV drugs ever seen. The search is on for equally powerful drugs without as many side effects. New non-nukes include:
TMC125 is so potent that all by itself it works as quickly as an extremely powerful five-drug combination. Human trials show that it works against HIV that's resistant to other non-nukes.
DPC 083 promises to be even stronger than Sustiva with fewer side effects. Human tests continue.
Integrase inhibitors target yet another crucial HIV target. Integrase is the sewing kit HIV uses to splice its own DNA into the DNA of a cell. There aren't yet any approved integrase inhibitors -- but that could change:
- S-1360 is a new drug already in human tests. It's worked very well in animal studies.
- Merck has an as-yet-unnamed integrase inhibitor ready for human tests, according to The Wall Street Journal.