Tag: clinical trials

How Effective Is the HPV Vaccine at Preventing Cancer? A Closer Look…

By Jeanne Lenzer | November 23, 2011 12:51 pm

Some people have taken issue with the conclusion and analysis in my previous post, “Should Boys Be Given the HPV Vaccine? The Science Is Weaker Than the Marketing,” including epidemiologist Tara Smith in her blog, Aetiology, at ScienceBlogs. Here’s a clarification of some of the points in my post, and a response to some of hers.

First I’ll reiterate the key point of my post: There are many, many instances in which researchers have promised cures and interventions that were expected to work based on eminently reasonable logic, but did not pan out. Take one recent recent example: bypass a clogged artery and you will prevent strokes (see Sharon Begley’s excellent blog post on “When Biology Refuses to Listen to Medical Logic”). And now comes one more eminently logical assumption: prevent cervical lesions from some strains of HPV in some people for some period of time, and you will save lives from cervical cancer overall. Unfortunately, while the two HPV vaccines on the market may decrease the serious illness and death from cervical cancer, no study has proved that at this point, since no study has been conducted long enough to observe the development of cervical cancer or cervical cancer deaths.

Conclusive studies with the most important, clinically relevant end points should precede wide uptake of any intervention. The data currently rely on surrogate end points (markers of possible cancer) and are simply not conclusive. So we can’t truly say how effective the vaccine is.

Wake Forest medical researcher Curt Furberg, a former FDA advisor and co-author of the textbook Fundamentals of Clinical Trials, told me, “Getting data from markers is a first step. But we have burned our fingers too many times with surrogate markers. You should try to determine the real health benefit. Everything will be up in the air until we have the answer to the question: Will it prevent cancer? And until we have that answer, we should limit its use to girls enrolled in studies of the vaccine.”

Here are some other reasons why the HPV vaccines may not be as effective as advertised:

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CATEGORIZED UNDER: Health & Medicine, Top Posts

How to Become a Trespasser in Your Own Genome

By Erika Check Hayden | October 19, 2011 7:58 pm

Gholson Lyon is on a crusade. It started last November, when he found out that a woman in a research study that he was conducting was pregnant. Lyon’s study had revealed that the woman carried a gene that causes a fatal disease. Yet he couldn’t tell the mother-to-be that she might be carrying a sick child due to the rules governing the study. The mother did give birth to a boy with the disease; he died in the same week that Lyon published his paper on the study, as I reported recently in Nature. Lyon was so disturbed by the situation that he is now trying to find a way for researchers to work within the rules so that they don’t face these same ethical dilemmas. And he is speaking and writing about the issue everywhere he can.

The issue of what to tell patients about their DNA is difficult enough for doctors who are treating patents rather than studying them. But it has become urgent for researchers as well, because genetic sequencing technologies are now cheap and fast enough that scientists are planning to sequence five thousand patients’ genomes this year, and as many as 30,000 next year. The US National Human Genome Research Institute will soon begin a program that will spend tens of millions of dollars to sequence the genomes of patients, like Lyon’s study subjects, who have rare genetic diseases. And researchers are also sequencing thousands of otherwise healthy people across the lifespan, from newborns to old folks.

Inevitably, researchers will find stuff in these thousands of genomes. Most of it will be difficult to understand. Some of it will clearly be linked to disease. Some of it will be newly linked to disease through these studies. The whole point of these studies is to link genes and disease. So it would seem like a good idea to tell the gracious volunteers who have donated their time and blood for these studies that they have certain genetic disease risks, right?

Wrong.

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CATEGORIZED UNDER: Health & Medicine, Top Posts
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