Opinion | Do Clinical Trials Work? (original) (raw)

https://www.nytimes.com/2013/07/14/opinion/sunday/do-clinical-trials-work.html

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Opinion

July 13, 2013

EVERY spring, some 30,000 oncologists, medical researchers and marketers gather in an American city to showcase the latest advances in cancer treatment.

But at the annual meeting of the American Society of Clinical Oncology last month, much of the buzz surrounded a study that was anything but a breakthrough. To a packed and whisper-quiet room at the McCormick Place convention center in Chicago, Mark R. Gilbert, a professor of neuro-oncology at the University of Texas M. D. Anderson Cancer Center in Houston, presented the results of a clinical trial testing the drug Avastin in patients newly diagnosed with glioblastoma multiforme, an aggressive brain cancer. In two earlier, smaller studies of patients with recurrent brain cancers, tumors shrank and the disease seemed to stall for several months when patients were given the drug, an antibody that targets the blood supply of these fast-growing masses of cancer cells.

But to the surprise of many, Dr. Gilbert’s study found no difference in survival between those who were given Avastin and those who were given a placebo.

Disappointing though its outcome was, the study represented a victory for science over guesswork, of hard data over hunches. As far as clinical trials went, Dr. Gilbert’s study was the gold standard. The earlier studies had each been “single-arm,” in the lingo of clinical trials, meaning there had been no comparison group. In Dr. Gilbert’s study, more than 600 brain cancer patients were randomly assigned to two evenly balanced groups: an intervention arm (those who got Avastin along with a standard treatment) and a control arm (those who got the latter and a placebo). What’s more, the study was “double-blind” — neither the patients nor the doctors knew who was in which group until after the results had been assessed.

The centerpiece of the country’s drug-testing system — the randomized, controlled trial — had worked.

Except in one respect: doctors had no more clarity after the trial about how to treat brain cancer patients than they had before. Some patients did do better on the drug, and indeed, doctors and patients insist that some who take Avastin significantly beat the average. But the trial was unable to discover these “responders” along the way, much less examine what might have accounted for the difference. (Dr. Gilbert is working to figure that out now.)

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