Sorry to hear about the nausea ladybugmandy. Are you taking anything else? Are you still on Valtrex?
if XMRV is the cause of CFS, shouldnt azt always work?
Not necessarily. AZT was shown to be helpful in stopping the virus from replicating in a lab study but the body is a far different environment. Researchers can easily stop cancer in test tubes for example but doing the same thing in the body is much more difficult.
Of course AZT has a track record with retroviruses - so they think it could work - but they don't really know.
You are right that just because something works in vitro does not necessarily mean something will work in vivo, this is usually because many things aren't absorbed into the blood stream very well. We know from HIV research that AZT is absorbed and can inhibit HIV in the body. Since AZT inhibits XMRV in vitro at a similar concentration that it inhibits HIV, I think it is pretty good evidence that it will work in vivo, short of a real clinical trial. If it was some new drug that had never been studied in vivo then much more skepticism about that drug's efficacy would be in order. When a new drug is discovered to do something in a test tube, they first do a Phase 1 trial on healthy volunteers. The Phase 1 trial is done to determine safety and to assess how the drug is processed and absorbed into the body (pharmacokinetics and pharmacodynamics). Of course we already know about AZT's pharmacokinetics etc.
What are some reasons AZT might NOT work? My guesses are
1. XMRV doesn't cause CFS
2. Drug resistance
3. Coinfections have overwhelmed the immune system. If this were the case, I would think AZT would still work, but take a longer period of time, a year or more possibly.
4. XMRV or a coinfection is being harbored in a body tissue where AZT can't reach
Cort said:
XMRV may not be doing its damage by replicating; as Dr Mikovits noted - it doesn't appear to replicate much; whatever it does it appears to do simply by sitting in the cell. I don't know if AZT hits viruses when they're not replicating.
I am not convinced this is the case, but if it is, immune modulators would probably help. Anything from ampligen, isoprinosine, beta glucan/AHCC, even echinacea could help. We would need to get the immune system to kill the infected cells.
Personally I think Isentress (raltegravir) is the drug to keep a close eye on. From the a combination of HIV in vivo and XMRV in vitro I wouldn't be surprised if raltegravir and low dose AZT became the standard of care for CFS, at least in the short term until pharma "invents" some new drugs specifically for XMRV/CFS. I am actually finally about to start Valtrex in a few weeks and I am really itching to get my hands on some raltegravir and AZT, although I will probably wait until we have more solid evidence.