Positive Life NSW

Nevirapine (Viramune)

Report by Jae Condon (Treatment and Support Officer- Positive Services and Health Unit, ACON)

The goal of HIV treatment is to reduce the amount of HIV in your blood to ‘undetectable’, thus enabling your CD4 count to increase and your immune system to return to optimal function. An undetectable result does not necessarily mean that there is no HIV in your blood, or other parts of your body, rather the test used cannot detect (find) any HIV in your blood.

Most tests used in pathology labs have a ‘sensitivity’ or ability to detect HIV at 40 or 50 ‘copies’ ¹ per ml or drop of blood. This means such tests cannot detect HIV below these levels, so someone with an undetectable result could still have active HIV in their blood below these levels. In recent years, new and more highly sensitive HIV viral load tests have been developed that can detect a viral load below one copy/ml. Although being undetectable at less than 1 copy/ml could be considered to be zero in plasma, or the liquid part of blood, HIV can still ‘hide out’ in parts of the body called reservoirs. Examples of these reservoirs include the brain, gut and the lymph nodes.

A team of French investigators has found that people who are taking an HIV treatment combination that includes Nevirapine (Viramune) are more likely to achieve a viral load of zero than people taking a combination that includes Efavirenz (Sustiva, also in the combination pill Atripla).

The researchers designed a retrospective study involving 75 patients treated with Nevirapine and 90 individuals taking Efavirenz-based combinations who had an undetectable viral load below 50 copies per ml of blood for at least six months using a test capable of detecting virus below one copy/ml. The results showed that 81% of people taking Nevirapine had a viral load of zero compared to 56% of individuals treated with Efavirenz.

Previous research has suggested that treatment combinations that include a drug from the NNRTI (non-nucleoside reverse transcriptase inhibitor) group of HIV drugs are more likely to suppress viral load to extremely low levels than treatment based on a protease inhibitor (PI), a different class of drug. There is also some evidence that Nevirapine is more effective at reducing viral load to lower levels than Efavirenz. The investigators believe that research demonstrates “the stronger ability of Nevirapine than Efavirenz to better control residual (HIV), in patients with (undetectable viral load).” They suggest that this is because Nevirapine is better able to penetrate “reservoirs”, or places in the body that HIV can ‘hide’ and treatments are unable to get to.

“The clinical relevance of having a viral load below 1 copy/ml has yet to be shown,” conclude the researchers, who call for studies “to explore, for example, the relationship between the level of (HIV) and systemic inflammatory or immune activation markers ².”

It’s currently unclear what the benefits are of having a viral load of zero. However, it’s known that even low levels of HIV can cause inflammation ³ and that this can increase the risk of some serious illnesses, for example cardiovascular disease and some cancers. Therefore including Nevirapine in your combination could in theory reduce the risk of developing these health issues. It is also theorised that the lower someone’s viral load the less chance they have of passing on HIV during unprotected sex, in the absence of another STI or lesion (cut or sore) to the genitals.

So . . .  is Nevirapine for me?

For people starting treatment for the first time with a combination that includes Nevirapine there is a risk of liver toxicity depending on your CD4 count. The risk is different for men and women. Men with a CD4 count above 400 per ml, and women with CD4s above 250 per ml, are at higher risk of experiencing liver related side effects if starting Nevirapine.

However people who have been taking other HIV treatments, have an undectable viral load and do not have resistance to Nevirapine can switch to Nevirapine quite safely. If you think you would benefit from taking Nevirapine, or would like to include it into your combination, you should discuss your options with your HIV doctor.

Reference:

Haïm-Boukobza S, Morand-Joubert L, Flandre P, Valin N, Fourati S, Sayon S, Lavignon M, Simon A, Girard PM, Katlama C, Calvez V, Marcelin AG. (2011) Higher efficacy of Nevirapine than Efavirenz to achieve HIV-1 plasma viral load below 1 copy/ml, AIDS. 2011 Jan 28;25(3):341-4.

Footnotes

1. The term ‘copies’ is used when giving HIV Viral Load (VL) results because pathology tests detect HIV genetic material, or the building blocks for HIV. This genetic material assembles to form new viral particles, which are then released from the CD4 cell to go on to form new immature HIV’s that must go through a process of maturation before they can recommence the replication cycle. Until the process of maturation is complete HIV is not yet able to start the replication cycle again, but the genetic material is still able to be detected by HIV Viral Load tests and is called a copy.
2. These terms refer to chemical markers measurable in blood. The level of these ‘markers’ give an indication of the amount of immune related inflammation caused by HIV. These chemical markers are thought to contribute to HIV related health issues such as premature signs of heart disease and other health issues related to HIV and ageing.
3. Even with effective treatment and an undetectable viral load, HIV continues to stimulate the immune system to release an ongoing or chronic inflammatory response by way of releasing pro inflammatory chemicals. Chronic inflammation can lead to a range of health issues for people with HIV. The higher ones viral load, the more likely a person will experience health issues related to inflammation.