3 HIV DRUGS WITH POSSIBLE EFFICACY AGAINST XMRV

Share |

This past spring, Dr. Ila Singh at the University of Utah conducted one of three recent studies testing HIV antiretrovirals against XMRV in vitro (in the test tube).  Singh discovered that two drugs—tenofovir and raltegravir—killed the XMRV retrovirus, and corroborated an earlier study by the Mayo Clinic that concluded that AZT is also effective against XMRV.  In addition, Singh found any two combinations of these three drugs were synergistic.  She didn’t test all three drugs together, so it’s not known if a triple cocktail would be even more effective.  It’s also possible that the triple cocktail could be less effective than a two-drug combo.

Likewise, a June 2010 study by the National Cancer Institute also found that AZT, tenofovir and raltegravir inhibit XMRV in vitro.  Here’s a capsule view of the three drugs:

Nucleoside Analogue Reverse Transcriptase Inhibitors

Zidovudine (brand name AZT).  FDA-approved in 1987, AZT was the first drug used to treat HIV/AIDS, though it was developed in the 1960s as a cancer drug.  In 1974, German scientist Max Planck discovered that AZT was active against a mouse retrovirus called Friend murine leukemia virus, a close cousin of XMRV.  In HIV, AZT works by stopping the enzyme reverse transcriptase from converting the retrovirus’s RNA into DNA, which is then integrated into the genetic material of the host’s cells. Normally DNA transcribes (converts) RNA.  Reverse transcription is the reverse: RNA transcribes DNA.  Nucleoside analogue reserve transcriptase inhibitors are often abbreviated NRTIs.

Common side effects of AZT include:  nausea, loss of appetite, headache, tiredness, vomiting, constipation, asthenia (weakness).  Less common side effects:  anemia, bone-marrow suppression, bruising, muscle pain and myopathy (muscle weakness), mitochondrial toxicity and lactic acidosis, body-fat redistribution, elevated liver enzymes and liver damage, a bluish discoloration of fingernails and toenails, and allergic reactions.  Nausea is the most common side effect from AZT and can be minimized by taking the drug with food.  However, high-fat meals tend to exacerbate the nausea.

Nucleotide Analogue Reverse Transcriptase Inhibitors

Tenofovir (brand name Viread).  Nucleoside analogs are converted into nucleotide analogs by the body. If you take nucleotide analog reverse transcriptase inhibitors (often abbreviated NtRTIs), you bypass that step.  FDA-approved in 2008, Tenofovir, like AZT, blocks the retroviral attack on the host’s healthy cells by preventing the reverse transcriptase enzyme from doing its job of transcribing single-stranded viral RNA into double-stranded viral DNA.

Common side effects of tenofovir include: diarrhea, headache, pain, depression, rash, asthenia (weakness), nausea.  Less common side effects:  vomiting, gas, loss of appetite, weight loss, insomnia, dizziness, sweating, muscle pain and myopathy (muscle weakness), mitochondrial toxicity and lactic acidosis, kidney and liver damage, Fanconi syndrome, exacerbation of hepatitis, decrease in bone density, elevated blood sugar, fast or irregular heartbeat, and allergic reactions.  Kidney toxicity can occur within the first few months of taking Tenofovir, so kidney function must be monitored.  Dehydration contributes to kidney toxicity and can be minimized by drinking more water.

Integrase Inhibitors

Raltegravir (brand name Isentress):  FDA-Approval in 2007, it’s the first and only approved integrase inhibitor, though others are in the pipeline.  Integrase inhibitors block a later phase of retroviral integration than NtRTIs or NRTIs do.  Raltegravir prevents the enzyme called integrase from inserting double-stranded viral DNA into the host cells’ DNA. 

Common side effects of raltegravir include: rash, headache, nausea, asthenia (weakness) and fatigue.  Less common side effects:  gastritis, abdominal pain, insomnia, dizziness, fever, anemia, diarrhea, insomnia, rash, kidney damage, kidney failure, high blood sugar, depression, and allergic reactions.

With HIV patients, one drug is started and a second drug in added one to two weeks later, and a third drug is added one to two weeks after that. 

Dr. Ila Singh discussing XMRV and the HIV drugs being tested in animals inoculated with XMRV:

Video Courtesy of KSL.com

This post should not be construed as medical advice.  Nor is this post an endorsement of the use of antiretrovirals for ME/CFS patients and an XMRV diagnosis.  I am a science writer, not a physician or a researcher.  Consult your health-care professional before beginning any treatment plan.

Coming up:  Drugs that may help clear XMRV reservoirs.  Plus an interview with the CDC's Dr. Steve Monroe, director of the CDC’s division of High Consequence Pathogens and Pathology.

This article is copyright CFS Central 2010.  All Rights Reserved. You may quote up to 150 words from this article as long as you indicate in the body of your post (as opposed to a footnote or an endnote) that the excerpt is by Mindy Kitei for CFS Central.  You may not reprint more than 150 words from this article on blogs, forums, websites or any other online or print venue.  Instead, refer readers to this blog to read the article.