By Chris Adams

Before doctors began using a drug known as T-DM1 to treat breast cancer in women whose previous therapy had failed, the drug had to clear hurdle after hurdle.

Researchers had to determine which patients might benefit from the drug trastuzumab-DM1, which is now sold as Kadcyla. They had to design a clinical trial that compared treatment with T-DM1 against treatment without it. And they had to enroll nearly 1,500 women to do so.

That process – from idea to approved therapy – was the focus of a session with National Press Foundation fellows by Dr. Larissa Korde, senior investigator for a cancer therapy evaluation program at the National Cancer Institute, which is part of the National Institutes of Health.

The approval of this use of Kadcyla was an important development for breast cancer treatment, but it wasn’t one of those $1 billion drug blockbusters that make it onto the evening news. Its coverage was mostly confined to the medical press.

Kadcyla had already been on the market when researchers began exploring additional uses for it. The most promising is for patients with a certain type of cancer – HER2-positive metastatic breast cancer – whose previous treatment had failed. (The findings, eventually reported in The New England Journal of Medicine, saw fewer deaths in the Kadcyla treatment arm than the other one – a success.)

Korde used Kadcyla and the KATHERINE trial that tested is as a case study of the drug development process.

She detailed the three stages of clinical trials: Phase 1, which tests the safety in a small number of people; Phase 2, which tests effectiveness; and Phase 3, which tests both safety and efficacy in a large group of patients, as well as comparing it against other treatments.

Korde also detailed the state of breast cancer treatment for various cancer subtypes, including the different treatment options, from surgery to radiation to chemotherapy and immunotherapy. The goal is not merely to develop new treatments, she noted.  “The gold standard is that by controlling disease, the patient lives longer.”