Getting the Right Test Can Determine the Right Treatment and So Can What the FDA Does

By Barbara Brenner

You may have noticed a recent New York Times article about the challenge of accurate testing to determine what drugs are appropriate for cancer patients, particularly breast cancer patients. As we’ve come to expect, the press was covering an issue we’ve been concerned about for some time.

Most of the widely touted progress in “personalized cancer care” has been made in breast cancer. The two most common “personalized” approaches have to do with testing for a tumor’s sensitivity to estrogen or progesterone (indicating the appropriateness of hormonal treatments like tamoxifen or an aromatase inhibitor), or testing for the overexpression of the Her2/neu protein (indicating the appropriateness of treating with Herceptin).

So far so good. But it turns out that the tests for these two things are not so easy to do, and quality control over the accuracy of the tests has been minimal. As a result, some patients who might benefit from hormonal or Herceptin treatment are scored as “negative” and never get the treatment. Others, who actually won’t benefit from the treatment, are incorrectly scored as “positive” and get treatment that won’t help them — and may have dangerous “side” effects. Still other patients, whose tests results are ambiguous, are cast into a sea of uncertainty.

The problem of these tests’ accuracy has been discussed by breast cancer activists for years. Finally, the American Society of Clinical Oncology (ASCO) and the College of American Pathologists have issued guideline recommendations for testing of both hormone receptors and Her2/neu. (The documents are very long and technical, but we’d be happy to send you copies of these guidelines if you’re interested in seeing them.)

The next step, of course, is to make sure that practicing oncologists and pathologists know about and follow the guidelines. Lots of guidelines have been issued that are never followed. And educating doctors in community practice is the hardest part of making guidelines real. Maybe ASCO and the College of American Pathologists will devote some resources to educating doctors beyond their already well-informed circle. We can hope.

Since the treatments for people whose cancers are either hormone positive or Her2 positive work for only some, we need more research to determine who will in fact benefit. We also need research into treatments that will work for those with the markers, but who don’t benefit from the drugs currently available.

Some of that work is happening — Genentech, the maker of Herceptin, is doing some of it. But in a dangerous twist, the company is urging the FDA to let it market drugs that have not been fully tested for efficacy and safety. They have approached the FDA for approval of a drug called TDM-1 (for patients whose breast cancer overexpresses Her2/neu, but for whom Herceptin has stopped working) on the basis of a single test of the drug in a study that did not involve a control arm of women getting standard treatment.

Since BCA is committed to making sure that drugs approved for the breast cancer market either prolong life, improve quality of life, or cost less than drugs currently on the market, we have asked the FDA to reject Genentech’s request for approval of TDM-1 at this time.

The positions we take are not always popular. But we’re not trying to win a popularity contest. We’re trying to make sure that decisions about the care patients receive are being made by people who have those patients’ interests foremost in their minds.

For additional notes and BCA thoughts on breast cancer developments, as discussed at the 2010 American Society of Clinical Oncologists (ASCO) meeting, click here.

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