Meet Science: How clinical trials work

Did you know that, with a properly conducted series of clinical trials, it can take upwards of 20 years before a medical discovery makes it from the lab to the hospital?

Judy Stone, an infectious disease specialist who does clinical research, has a guest post on the Scientific American blog network today, explaining the basics of clinical trials—where they came from, and how they can go wrong.

She's going to be publishing a series of posts on this topic, and is looking for input on what you want to know about clinical trials. Disclaimer: As a clinical researcher, Stone has a goal here. She'd like to see more people volunteering for clinical research, and part of what she's interested in is the gaps in knowledge that make people wary of participating, or leave them unaware that they can participate. Your input would be helpful.

Image: Pills Phial, a Creative Commons Attribution Share-Alike (2.0) image from luca_volpi's photostream

Clinical trials seek to learn whether a drug (or device) works as expected—it's unknown, until tested in people. That's why early phase trials use only a few people, and more are added as experience is gained. Sometimes unexpected discoveries are made along the way. For example, Rogaine was discovered by an astute clinician researcher during a clinical trial studying high blood pressure. The drug, minoxidil, originally under study as an anti-hypertensive medication, was serendipitously found to have the unexpected side effect of stimulating hair growth, prompting a whole new line of products for baldness.

Similarly, Viagra was discovered by accident. Sildenafil, the generic form, was being studied as a treatment for angina, as it dilates blood vessels by blocking an enzyme, phosphodiesterase (PDE). While not very effective for angina, it was found to prolong erections, stimulating the whole "life-style drug" industry. Fortunately, PDE inhibitors are now being found useful for a host of important medical conditions, ranging from pulmonary hypertension to asthma and muscular dystrophy.

Of course, not all inadvertent discoveries have such rosy outcomes.

For example, Diethylstilbesterol (DES), a synthetic estrogen, was commonly prescribed in the US 1938-1971, to help prevent miscarriages. It was only after many years that DES was found to cause a rare type of vaginal cancer in daughters of exposed women. Later, other types of cancers showed up as well, in small numbers.

Via Aaron Rowe