NPR Story
3:08 pm
Tue May 20, 2014

NIH: Scientists Must Include Female Animals In Testing

The National Institutes of Health will soon begin requiring scientists to test new drugs on both male and female animals. Researchers now tend to use mostly male animals in pre-clinical tests, even for drugs that will also be used by women.

But that has had some major consequences for women.

Here & Now’s Jeremy Hobson talks to Dr. Janine Clayton, director of the Office of Research on Women’s Health at the National Institutes of Health, about why the gender of research animals matters, and the new requirements NIH is going to be phasing in for scientists.

Interview Highlights: Janine Clayton

On why scientists typically use male animals

“I think part of it is really — not intentionally, but really, that it is a blind-spot. Some people think that using female animals is more difficult because of female hormonal cycling. But we’ve shown, others have shown, and in that analyses, a collection of studies, that that is just not true. They actually looked at male and female animals and found that the female animals were no more variable than the male animals, and in fact, the males were more variable than the females in some important ways.”

On the importance of researching drug effects on females

“There really can be big differences, and we’ve seen that, for example, with aspirin, which helps to prevent heart attacks in men, but is helpful for stroke prevention in women. And we see that in nicotine patches, for example, that work much more effectively in men than women. So we do know there are differences. Despite that, our pre-clinical research, that research that tests things before they go into the clinic, we just see many, many more male animals than female animals being used.”

On criticism that the new research is too expensive

“I would say that we’re either gonna pay now, or we’re gonna pay later, and really, our best money spent is on the most optimal experimental design. And we’re about funding the best science possible, and rigor and excellence and high-quality research is what NIH is about.”

Guest

  • Janine Clayton, director of the Office of Research on Women’s Health and associate director for Research on Women’s Health at the National Institutes of Health. She tweets @JanineClaytonMD.
Copyright 2014 WBUR-FM. To see more, visit http://www.wbur.org.

Transcript

JEREMY HOBSON, HOST:

And here in this country, the National Institutes of Health is going to begin requiring scientists to test new drugs on both male and female animals. Researchers now tend to use mostly male animals when they're testing new drugs, even if those new drugs will also be used by women.

Dr. Janine Clayton is associate director for research on women's health at NIH. She's with us now. Welcome.

JANINE CLAYTON: Happy to be here.

HOBSON: Why is that? Why do scientists generally prefer to use male animals in their research?

CLAYTON: I think part of it is really - not intentionally, but really, that it is a blind spot. Some people think that using female animals is more difficult because of female hormonal cycling. But we've shown, others have shown, and in that analyses, a collection of studies, that that is just not true.

They actually looked at male and female animals and found that the females were no more variable than the male animals, and in fact, the males were more variable than the females in some important ways.

HOBSON: When you say hormonal cycling, what do you mean by that?

CLAYTON: There's an estrous cycle, which is comparable to a female menstrual cycle, that rodents have. And that does cause change in some measures. But it's not all of the measures, in fact, it's not most of the measures.

HOBSON: And even given that, it seems counter-intuitive that scientists wouldn't want to know how drugs work differently in males and females, because, of course, there are big differences.

CLAYTON: Absolutely. There really can be big differences, and we've seen that, for example, with aspirin, which helps to prevent heart attacks in men, but is helpful for stroke prevention in women. And we see that in nicotine patches, for example, that work much more effectively in men than women. So we do know there are differences.

Despite that, our pre-clinical research, that research that tests things before they go into the clinic, we just see many, many more male animals than females being used.

HOBSON: Well, what is the effect of that?

CLAYTON: What happens when you make decisions based on incomplete information is you lose your certainly about the expectation of what you'll find. And in research we really like to use evidence. We use - we want to make evidence-based decisions in clinical care. And if we don't have sex-specific evidence, data from males and females in animal or cell studies, we're making decisions without appropriate information. We're getting half of the story and not the whole story.

HOBSON: And all this does make you wonder why when you go into the pharmacy and buy an over-the-counter drug, most of the time there is not a separate set of directions for men and women. We're all told to take the same dosage.

CLAYTON: Well actually, there is some information that's sex-specific on drug labeling and that is related to zolpidem or Ambien. There's a decrease in the recommended dosage that the FDA has come out based on sex-specific data. They decreased the recommended dosage from 10 milligrams to 5 milligrams for women, and that is on the label.

But you're right, for the most part there isn't. As we go forward, if we do consider males and females and look at their data separately, we will be in position to put that kind of information on the labels. And there are situations where information is shared such that this drug has a higher rate of a particular affect in men or women, but that really is the exception at this point.

HOBSON: So what happens now? How do you get this to change, and I see that starting in October things will change. But what's going to happen to make sure that there is that balance between male and female research animals?

CLAYTON: So what we're going to be doing is attacking this from multiple fronts. We will be starting with some training material so that the scientific community knows what we expect and can understand what it is they need to do to incorporate this perspective. We will be rolling out our policies that explain clearly what is desired. And we'll be modifying our review and our compliance practices to make sure that this is incorporated into pre-clinical research.

HOBSON: And how do you respond to criticism that this is going to cost them a lot more money?

CLAYTON: So, I would say that we're either going to pay now or pay later. And really, our best money spent is on the most optimal experimental design. And we're about funding the best science possible, and rigor and excellence and high-quality research is what NIH is about.

HOBSON: Dr. Janine Clayton, associate director for research on women's health at the NIH. Dr. Clayton, thanks so much.

CLAYTON: Thank you for having me.

HOBSON: And you're listening to HERE AND NOW. Transcript provided by NPR, Copyright NPR.

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