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African Americans, Women Have Lower Virologic Response Rates in Both Arms of Head-to-Head Antiretroviral Trial

An Interview With Kimberly Smith, M.D., M.P.H.

July 20, 2009

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There's nothing like hearing the results of studies directly from those who actually conducted the research. In this interview, you'll meet one of these impressive HIV researchers and read her explanation of a study she presented at the 5th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention (IAS 2009).

I'm Kimberly Smith from Rush University Medical Center in Chicago. I am presenting the race and gender analysis of the HEAT study.1 The HEAT study is a study of naive, HIV-infected folks [N = 688], comparing abacavir [ABC, Ziagen] combined with 3TC [lamivudine, Epivir] and lopinavir/ritonavir [LPV/r, Kaletra] versus tenofovir/FTC [tenofovir/emtricitabine, TDF/FTC, Truvada] and lopinavir/ritonavir, with the lopinavir/ritonavir dosed once daily in both arms. [For a summary of the HEAT study, click here.] The overall analysis of the HEAT study, which is now actually published in AIDS this month, showed no difference between the arms.2

Kimberly Smith, M.D., M.P.H.
Kimberly Smith, M.D., M.P.H.
What we're presenting here is an analysis looking at race and gender. We're looking to see if there's a difference in responses by race or by gender. To make a long story short, we showed that both African Americans and women responded less well to both arms [at week 96 of the study]. The overall response rate for each of the arms for African Americans was roughly 50% undetectable at a level of less than 50, whereas for Caucasians, it's roughly 70% -- a pretty big difference.

For women, the difference is somewhere around 55% versus men being closer to 70%. Clearly, there's a little bit of a less good response in women and African Americans. The next question is why. I wish we could answer that, but we can't. But I will say that in a lot of studies, that difference is thought to be driven by adherence, or dropout.

In this study, it was a difference in virologic response. So it's not just about more African Americans dropping out of the study, or more African Americans not completing the study due to whatever variety of reasons. This is actually virologic differences.

Of course, the virologic differences can be driven by a lot of underlying things. Some of it could be a little bit of toxicity. Some of it could be a little bit of adherence challenge. It could be a number of things. But it's the kind of thing that I think should stimulate more research.

So I think this study is now added to a group of studies that have shown that there can be racial differences in response to therapy. I think it really implores us to look harder at these studies and take the next step, which is not only just to recognize that a difference exists, but to actually start to address how do we get rid of the difference. How can we design studies that intervene in a way that we can have all of the racial groups, and both men and women, responding equally to the antiretroviral therapies?

Do you have plans to continue this study?

This study is done, so we learn from this study. I've actually been sitting here the whole day talking with every pharmaceutical company that comes along about doing a meta-analysis where we can bring all of the naive studies together, and do some race and gender analysis so that we can have a bigger picture with a larger population. We're in the process of doing that for ACTG [AIDS Clinical Trials Group] studies.

So I think when we understand it better, then the next step will be to design studies that allow us to intervene. If you can identify who are the individuals that are at highest risk for virologic failure, then you can intervene before they fail, instead of waiting until the end of the study and saying, "Oh, blacks didn't respond as well." Let's identify who are the folks that are at risk for failure and do something to help them be successful within the study. I think that's what we need to do that's best for the patients. That's what we try to do in our clinic and that's what we need to do in the clinical trials. I think that if we can create strategies within clinical trials, those will be helpful for people in the clinic to be able to use in their day-to-day care.

Absolutely. Great, thank you so much.

This transcript has been lightly edited for clarity..


  1. Smith KY, Kumar PN, Patel P, et al. Differences in virologic response among African-Americans and females regardless of therapy in the HEAT study. In: Program and abstracts of the 5th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention; July 19-22, 2009; Cape Town, South Africa. Abstract MOPEB033.
    View poster: Download PDF
  2. Shaefer MS, Smith KY, Patel P, et al, for the HEAT study team. Randomized, double-blind, placebo-matched, multicenter trial of abacavir/lamivudine or tenofovir/emtricitabine with lopinavir/ritonavir for initial HIV treatment. AIDS. July 31, 2009;23(12):1547-1556.

This article was provided by TheBodyPRO. It is a part of the publication The 5th International AIDS Society Conference on HIV Pathogenesis, Treatment and Prevention.


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