"AIDS is no longer a death sentence for those who can get the medicines," said former US President Bill Clinton. "Now it's up to the politicians to create the comprehensive strategies to better treat the disease."
There are over 27 anti-HIV medications used in various combinations to treat HIV/AIDS but resistance and side-effects remain a major concern. Resistance is when medicines lose their ability to fight HIV. Some drugs become less effective while others become completely useless. Resistance is brought about by mutations, changes in the genetic make-up of HIV.
The sad thing about resistance is that often, resistance to one medication means resistance to an entire class of medications. ARVs traditionally fall into three classes of drugs:
One, Nucleoside Reverse Transcriptase Inhibitors (NRTIs) such as Zidovudine- formerly called azidothymidine or AZT- which interfere with HIV replication by inhibiting viral reverse transcriptase.
Two, Non-Nucleoside Reverse Transcriptase inhibitors (NNRTIs) which cause conformational changes at the active site of HIV reverse transcriptase thereby inhibiting its activity.
Three, Protease Inhibitors (PIs) which stop HIV replication by preventing the enzyme protease from cutting the virus into shorter pieces that it needs to make copies of itself in newly infected body cells.
Resistance has therefore been recorded with drugs belonging to these three classes: NRTIs, NNRTIs and PIs. In order to circumvent the current problem of resistance, it is important that new drugs- preferably drugs in classes other than NRTIs, NNRTIs or PIs ' are found. And that's exactly what has happened.
The first oral treatment that prevents HIV from entering uninfected body cells was approved by the US Food and Drug Administration on August 6, 2007. The European Medicines Agency committee also recommended its approval in June.
The new wonder drug is maraviroc, manufactured by Pfizer. Maraviroc is the first CCR5 inhibitor to be licensed for use as an anti-HIV medication. Maraviroc, selling under the tradename Selzentry, is the first in the class of Entry Inhibitors, drugs that prevent the passage of HIV into host cells.
HIV attaches to a site on our T-cells called the CD4 receptor. T-cells are the soldiers of the immune system that enable us to fight infections. The CD4 receptor is like a window through which HIV enters into body cells. But for efficient entry, HIV attaches to another spot on our T-cells called the CCR5 co-receptor. The CCR5 molecule acts as the most efficient door through which HIV enters into our T-cells.
CCR5 entry inhibitors change the molecular shape of CCR5, thereby preventing HIV from binding to our cells. When HIV fails to bind our body cells, it means that the HIV life cycle can't continue. Checkmate.
Because maraviroc is the first drug in this new class of drugs, people living with HIV will not have developed resistance, since they have not yet been exposed to similar drugs from this class before.
Patients taking the drug are advised against taking St. John's wort (Hypericum perforatum) as it lowers levels of Selzentry in the blood. St. John's wort is a herbal treatment for depression.
The drug does not lower the risk of passing HIV to other people through sexual contact.
But like many other drugs, Selzentry comes at a small price: liver toxicity and the possibility of heart attacks.
Other side effects may include immune reconstitution syndrome, cough, fever, colds, rash, muscle and joint pain, stomach pain and dizziness. That's the small price we have to pay, but who cares, as long as life goes on.
Let's love people living with HIV/AIDS. After all, compassion ' no, reconciliation ' is the foundation of this region. I love you all.
l Kazhila Chinsembu is a molecular biologist at the University of Namibia. Email comments: kchinsembu@unam.na
