Question

Viral load and drug choice with HIV-2 infection: do not use NNRTIs

30 May 2008. Related: All topics, Opportunistic infections, Resistance, Starting treatment.

Hi, could you let me know if the viral load test will pick up which type of HIV one has. For example HIV-1, or HIV-2, or both.

I was originally diagnosed abroad with HIV-1 and HIV-2

When I returned to UK , I started treatment with Kivexa (abacavir + 3TC) and Sustiva (efavirenz). I have been on treatment for over two months now.

BUT, I just read on NAM website that Sustiva is not active against HIV-2. What should be my course of action?

thanks

Answer

Answer: Simon Collins

Although early viral load tests were not all sensitive to HIV-2, more recent tests can sometimes be used for both viruses. Either this, or two separate tests should be used. This means that you should get two results each time, one for each virus.

If your clinic knows you have both infections, they should be using the appropriate tests. From the other part of your question I would not take this for granted – I think you need to check directly.

You are right that NNRTIs (Sustiva/efavirenz or Viramune/nevirapine) are not sensitive to HIV-2.

Where in the UK are you being treated?

Because this is so well known, I can’t understand why you were prescribed this combination. The potential risk is that while you are using three drugs to treat HIV-1 (which should bring your HIV-1 viral load down quickly), you are only using 2 drugs (abacavir and 3TC in Kivexa) to treat HIV-2.

This is a serious concern, because it means that your HIV-2 could very easily develop resistance to the abacavir and 3TC, both of which are very vulnerable to resistance if not used in a combination of three drugs. Given that HIV-2 has fewer drugs to treat, it is important that you don’t develop this resistance.

As you have only been on treatment for a couple of months, things may still be ok, but I think you should contact your clinic with a view to checking this asap. I would expect your clinic would now want to change the efavirenz to an alternative third drug that is also active against HIV-2, within the next week.

I would also recommend taking a blood sample for HIV-2 viral load and resistance tests before switching so that you can check whehter you are still sensitive to either 3TC and/or abcavir. Don’t wait for these results before changing treatment. If you swithc the efavirenz to a boosted PI this will be fine for the 1-2 weeks that the results may take to come back.

Even though HIV-2 is generally a more slowly progressing virus, it is important that you don’t loose treatment options now through sub-optimal 2-drug therapy.

Please give us a call if you want to talk about any of this, including alternative treatment options for the efavirenz.