T

he discovery five years ago was hailed as a breakthrough in the British media: Red blood cells could be made from embryos left over from fertility treatments, creating an unlimited supply of blood for transfusions.

The idea, according to comments attributed to scientist Marc Turner in an August 16, 2010, article in The Independent, was that “synthetic blood made on an industrial scale would overcome the problem of blood shortages and the risk of transmitting new infections between donors and recipients.”

It promised to have a major clinical impact — and soon. “If all goes to plan, the first clinical trials of synthetic blood made from embryonic stem cells could begin within five years,” the newspaper said.

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So, here we are five years later. Did all go to plan?

Before answering that question, here’s a bit about why we’re asking it. If you’ve been reading coverage of science and medicine as long as we have, you’ll no doubt have noticed how frequently scientists make predictions — often to journalists — about when a potential drug will be tested in clinical trials, or become available to patients. And it’s not just your imagination: A recent study of news reports from 2010 to 2013 found that about 70 percent of stories about stem cells that provided timelines “predicted that the clinical promise of [stem cell] research would be realized within 5 to 10 years or sooner, just around the corner, or in the near future.”

It wasn’t just the news media making bold unsubstantiated claims: Scientists were cited in nearly 70 percent of the stories that made such claims.

Exaggerated predictions aren’t confined to stem cell research. Take the case of Dr. Judah Folkman, the late Harvard researcher whose work, Nobelist James Watson told the New York Times in 1998, would cure cancer within two years. You may have missed the “cancer cured!” memo in 2000 — we did — though the research has definitely led to advances in the treatment of certain cancers. For example, doctors can now use several different drugs that block the growth of blood vessels that feed tumors throughout the body, such as in the brain, colon, lung, and kidney. So even when original claims never come to pass, scientists often uncover other promising opportunities in the lab or clinic.

Genetics is another field in which press coverage tends toward the breathless, and university news releases routinely overstate findings in many areas of research.

There are many reasons why results might be proclaimed as more promising than they are — scientists might hype their findings to journalists to get their research covered, journalists might select only promising data to share, or both might get taken over by the PR machinery that promotes the work of journals and universities. Or occasionally, findings turn out to be the product of fraud. To be fair, science is inherently unpredictable, so even when scientists and journalists do everything right, they will still get it wrong sometimes.

Periodically in this column, we’ll take a look back at claims made by scientists five years earlier to see how they hold up, and if they were off-target, explore why. Think of it as Five Year Watch.

Now back to the 2 million pints of blood per year that The Independent reported the stem-cell method would produce. We’re toward the end of 2015, which means trials should have begun by now, according to that story’s prediction. They haven’t; no such trial is listed at the UK clinical trials registry (nor the US registry, for that matter), where it would need to appear in order to ever be published. A 2012 strategy report from the Scottish National Blood Transfusion Service said that trials would not begin until April 2016. Even that statement was overly optimistic.

Turner, director of the Scottish transfusion service in Edinburgh, told STAT by email that he and his colleagues are now planning a trial that would start in 2017, but using a method not based on embryonic stem cells, which have proved challenging.

He said he never spoke directly to The Independent, and added that in comments to other reporters, “I don’t think I would have been as firm as saying that we were planning to do clinical trials in 5 years. … In response to media questions I think I said it would be at least a further 5 years and probably at least 10-15 years before this technology could reach clinical practice.”

Turner told us he’s not aware of any other scientists who have launched a clinical trial of the embryonic-stem-cell approach. Neither does he know of anyone who has begun a similar trial to generate blood from induced pluripotent stem cells, which can be generated without using embryos but behave similarly to embryonic stem cells.

“There are a number of issues [with stem cells], which we and the other groups in the field are working on,” Turner said, including coaxing immature cells to develop into specific cell types, making them more like typical red blood cells, and solving “complex manufacturing challenges.”

Bottom line? Not the five years predicted, but some progress. Stay tuned.

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