Navigation Links
Viral 'fitness' explains different resistance patterns to aids drugs

Some HIV medications lead to the development of drug-resistant HIV when patients take as few as two percent of their medications. For other medications, resistance occurs only when patients take most of their pills. These differences appear to be explained by the different levels of viral "fitness" of the drug-resistant HIV, say AIDS researchers in a new study.

The research, led by David Bangsberg, MD, MPH, an AIDS specialist at the University of California, San Francisco, is reported in the January 9 issue of the journal AIDS.

Viral "fitness" refers to the inherent ability of a virus to replicate and cause disease. Incomplete pill-taking by patients causes HIV to mutate and become resistant to the effects of the medications, while the medications that were consumed, in turn, cause the newly resistant virus to become less fit.

The type of medication also factors in. Differences in viral fitness of mutated resistant virus occur between different classes of antiretroviral drugs, said Bangsberg, who is an associate professor of medicine at UCSF and director of the UCSF Epidemiology and Prevention Interventions Center at San Francisco General Hospital Medical Center.

When patients succeed in completely suppressing HIV, which requires that patients take all or almost all of their medications as directed, resistant strains either do not occur or are suppressed, he added.

Explaining the study results, Bangsberg said, "A non-nucleoside reverse transcriptase inhibitor (NNRTI), for example, can be taken one time by a pregnant woman to prevent mother-to-child transmission, and NNRTI-resistant HIV virus can develop. Yet patients taking unboosted protease inhibitors (PI) do not experience the peak risk of PI-resistant HIV developing unless they are taking most of their PIs but fall just short of full viral suppression."

The researchers found that NNRTI-resistant virus has an advantage over sensitive virus even at very low levels o f adherence. This happens because only a single mutation is required to create high-level NNRTI resistance and these mutations have little impact on the virus's ability to replicate. PI-resistant virus, in contrast, requires multiple mutations, each of which significantly weakens the ability of the virus to replicate. These PI-resistant viruses only emerge, therefore, when challenged with high concentrations of drug.

Overall, study findings showed that NNRTI resistance was found less often than PI resistance among patients who took the pills as directed.

"We believe that when new drug classes are developed, more attention should be given in defining how virologic fitness determines how different patterns of taking medications may lead to resistance" said Steven Deeks, MD, associate professor of medicine at UCSF's Positive Health Program at SFGHMC and senior author on the study.

Both NNRTIs and non-boosted protease inhibitors are potent antiretroviral drugs (ARVs) with demonstrated effectiveness in suppressing the HIV virus when taken in combination with other ARVs at high levels of pill-taking as directed. The standard combination therapy usually includes either one NNRTI or protease inhibitor (non-boosted or boosted with a small amount of another potent PI) and two different antiretrovirals from the nucleoside reverse transcriptase inhibitor class.


'"/>

Source:University of California - San Francisco


Related biology news :

1. Viral DNA sequence a possible trigger for breast cancer
2. NYU Study Reveals How Brains Immune System Fights Viral Encephalitis
3. Viral protein influences key cell-signaling pathway
4. Viral protein helps infected T cells stick to uninfected cells
5. Viral genetic differences are possible key to HIV dementia
6. Viral hitchhiker inhibits Wolbachia bacterias ability to proliferate
7. Viral marker of human migration suspect
8. Viral protein is an effective preventative against infection
9. Gene sequencing explains bioremediation bug
10. New book explains antibiotic resistance for a broad audience
11. UGA study explains peaks and troughs of dengue epidemics
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:2/2/2016)... YORK , Feb. 2, 2016 ... of that Rising Market Are you interested ... analysis forecasts revenues for checkpoint inhibitors. Visiongain,s report ... market, submarket, product and national level. Avoid ... discover what progress, opportunities and revenues those emerging ...
(Date:2/2/2016)... 2, 2016  Based on its recent analysis ... recognizes US-based Intelligent Retinal Imaging Systems (IRIS) with ... for New Product Innovation. IRIS, a prominent cloud-based ... America , is poised to set the ... retinopathy market. The IRIS technology presents superior price-performance ...
(Date:2/1/2016)... Fla. , Feb. 1, 2016  Wocket® smart wallet ( www.wocketwallet.com ... and television personality, Joey Fatone . Las Vegas ... greet fans. --> Las Vegas , where ... --> The new video ad was filmed at the Consumer ... appeared at the Wocket booth to meet and greet fans. ...
Breaking Biology News(10 mins):
(Date:2/11/2016)... , ... February 11, 2016 , ... ... its new stem cell treatment clinic in Quito, Ecuador. The new facility will ... trauma applications to patients from around the world. , The new GSCG ...
(Date:2/10/2016)... WASHINGTON , February 10, 2016 Early-career ... , Peru , Uganda ... their life-enhancing work in health and nutrition   Indonesia ... Uganda and Yemen are ... sciences and epidemiology. They are also celebrated for mentoring young women scientists ...
(Date:2/10/2016)... 2016 NX Prenatal Inc., a US ... technology for early warning of adverse pregnancy outcomes, ... study by Dr. Thomas McElrath of ... Fetal Medicine,s (SMFM) annual meeting held in ... 2016.  The presentation reported initial positive top-line results ...
(Date:2/10/2016)... York (PRWEB) , ... February ... ... (NASDAQ: REGN) today announced that it has joined the Human Vaccines Project, ... for infectious diseases and cancer. , The Human Vaccines Project brings ...
Breaking Biology Technology: