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:3/31/2016)... -- Genomics firm Nabsys has completed a financial  restructuring under ... M.D., who returned to the company in October 2015. ... including Chief Technology Officer, John Oliver , Ph.D., ... Vice President of Software and Informatics, Michael Kaiser ... Bready served as CEO of Nabsys from 2005-2014 and ...
(Date:3/22/2016)... India , March 22, 2016 /PRNewswire/ ... market research report "Electronic Sensors Market for Consumer ... Proximity, & Others), Application (Communication & IT, ... Geography - Global Forecast to 2022", published ... industry is expected to reach USD 26.76 ...
(Date:3/18/2016)... 18, 2016 --> ... ICT, Manned & Unmanned Vehicles, Physical infrastructure and Perimeter Surveillance ... in the border security market and the continuing migration crisis ... Europe has led visiongain to publish this ... --> defence & security companies in the ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... Andrew D Zelenetz ... Published recently in Oncology ... touchONCOLOGY, Andrew D Zelenetz , discusses the ... is placing an increasing burden on healthcare systems ... With the patents on many biologics expiring, interest ...
(Date:6/23/2016)... ... June 23, 2016 , ... ClinCapture, the ... Convention Center and will showcase its product’s latest features from June 26 to ... a scientific poster on Disrupting Clinical Trials in The Cloud during the conference. ...
(Date:6/23/2016)... ... June 23, 2016 , ... Velocity Products, a division of ... and optimized exclusively for Okuma CNC machining centers at The International Manufacturing Technology ... among several companies with expertise in toolholding, cutting tools, machining dynamics and distribution, ...
(Date:6/23/2016)... 23, 2016 ReportsnReports.com adds ... to its pharmaceuticals section with historic and forecast ... much more. Complete report on the ... profiling 15 companies and supported with 261 tables ... . The Global Cell Culture ...
Breaking Biology Technology: