The following is a guest post from Andrew Holtz, one of our longtime contributors, who is an independent health journalist based in Portland, Oregon. Andrew has been a medical correspondent for CNN and is past president of the Association of Health Care Journalists.
One in seven. That’s how many cancer drugs approved using surrogate endpoints (such as tumor response or progression-free survival) actually demonstrated they helped patients live longer, according to a study that looked at the evidence available on such drugs more than four years after their approval.
That track record is important because news reports… and patient hopes… shoot up, with glowing talk of breakthroughs or at least promising results, based on exactly this sort of surrogate endpoint study. And why shouldn’t they? After all, when the US Food and Drug Administration approves a drug, that means it works, right? Well, that depends on your definition of “works”.
Here’s what the study authors, Chul Kim, MD, MPH and Vinay Prasad, MD, MPH, reported in JAMA Internal Medicine. They found that from 2008 through 2012, the FDA approved 36 cancer drugs based on surrogate endpoints; that is, the FDA didn’t require drug makers to wait until they finished studies demonstrating patients lived longer. Drugs can be approved based on such evidence when they are given “breakthrough” designation by the FDA, which means that the drug “treats a serious or life-threatening condition” and “may demonstrate a substantial improvement…over available therapies.” There is understandable demand to get new drugs for serious conditions into the clinic. But when a drug is approved based on its ability to shrink tumors or at least stall their progression, drug makers are supposed to keep studying… in order to find out whether or not patients actually live longer, which is, after all, the main point of treatment.
The problem is that after all the initial hope and hype… only five of these 36 drugs were shown to actually help people live longer (see figure). Eighteen of the drugs failed to show real survival benefits in follow-up studies. And for the remaining 13 there was just silence. After more than four years either they had not been tested or survival results had not been reported.
The researchers point to Avastin (bevacizumab) for metastatic breast cancer as the poster child, not in a good way, of this post-approval-party hangover. The drug was approved for this use based on study results showing better progression-free survival. But the hoped-for real survival boost not only failed to materialize for these patients, experience revealed harm from side effects serious enough that the FDA ordered Avastin’s maker to add warnings to the drug label for hazards including “ovarian failure in premenopausal women, osteonecrosis of the jaw, and the risks of venous thromboembolic events”.
So rather than headlining the health report with “The FDA has approved a promising new cancer drug,” perhaps it would be more accurate, if less exciting, to report, “The FDA has approved a new cancer drug that based on recent experience probably won’t work.” Okay, maybe that line is too much of a downer. But journalists can at least be more diligent about applying good old skepticism to reports that a new drug has shown it can shrink or stall tumors, because based on this review of recent experience, odds are those surrogate endpoints have only a one in seven chance of translating into something people really care about: longer life.
Publisher’s note from Gary Schwitzer: on Twitter, Milwaukee Journal-Sentinel reporter John Fauber wrote, “Gratifying to learn that a JAMA Internal Medicine paper on new cancer drug approvals confirms our investigation from last October.” It should be gratifying. Fauber’s piece was important journalism. If you haven’t read it, I encourage you to do so.