A new class of ARVs – fusion/entry inhibitors
One of my regular readers wrote to me and said “Little is talked about entry/fusion inhibitors and intergrase inhibitors which sound compelling in the effort to eliminating HIV,” so I have taken him up on the offer and I write below about ARVs that are fusion/entry inhibitors.
The HIV life cycle involves several steps from entering the body, to entering the target CD4 T cells, making copies of itself inside the CD4 T cell and then escaping from the cell. There are several classes of antiretroviral drugs, each with a different site of action in the HIV life cycle. Entry/fusion inhibitors work to stop the virus from entering the CD4 T cell.
ARV therapy is successful for most patients. However, in some instances, the virus becomes resistance to multiple drugs. Fusion inhibitors are a class of drugs that have been recommended in countries such as Australia and the USA to treat multiple drug resistance.
Enfuvirtide was the first available and HIV fusion inhibitor. It is used with other antiretroviral drugs and is administered by injection twice daily.
Fuzeon (Enfuvirtide) works by stopping the virus and the cell from fusing. Think of the virus as a small army and your CD4 T cell is a country with an immigration border—what normally happens is that when the small army (virus) gets to the border (CD4 T cell), they bribe an official to let them in and what the official does is he opens a secret passage way into the country for the army. What fuzeon does is that it prevents that corrupt official and army from meeting.
The daily injections have made Fuzeon unpopular as a treatment option. Studies have been conducted in China on another fusion inhibitor called Albuvirtide which has been found to be effective with less frequent dosing. The trials in China found that once a week injection could be effective.
HIV is a smart virus; think of it as a small tiny army that invades your country and then rapes, pillages and grows into a bigger army with more soldiers that leaves your country and “infects” other countries.
Blocking any step in the entry process will interfere with HIV growing into an army with more soldiers. This is even more effective when entry inhibitor drugs that work by stoping different ways of entering can be used together.
