Study finds more isn't better for Roche breast cancer drug

Minneapolis

FOR more than a decade, women with a dangerous form of breast cancer have relied on Roche Holding AG's blockbuster drug Herceptin, taking the US$76,700-a-year medicine for 12 months to fight off the disease.

A new study finds that they may be able to cut their treatment in half. According to research released on Wednesday, women taking Herceptin for six months were just as likely to be free of cancer four years later as those who used the drug for a year, the current standard of care recommended by the US Food and Drug Administration and Roche.

"Our field is maturing," said Bruce Johnson, chief clinical research officer at the Dana-Farber Cancer Institute in Boston and president of the American Society of Clinical Oncology, or ASCO. "When we didn't have very many treatments that worked, we kind of threw the kitchen sink at it. We are beginning to learn we can change the status quo. We've been able to back off on some of the treatments."

The shorter duration also cut in half, to 4 per cent, the number of women who had to stop the drug early because it was harming their hearts - a well-known side effect of the drug. Experts cautioned that the study has substantial implications, but said that more research will be needed before a wholesale change in medical practice.

The research will be presented next month at the American Society of Clinical Oncology's meeting next month in Chicago, part of the cancer research convention's focus on precision medicine and refining existing treatments, even as much of the cancer world's attention has been captured by exciting new therapies that use the immune system and genetic approaches.

Herceptin was a lifesaving breakthrough for women with aggressive and fast-growing HER-2 positive cancer when it was approved in 1998, offering the first targeted treatment for the tumours. It quickly became a best-seller and generated US$7 billion in annual sales at its peak last year for Basel, Switzerland-based Roche. Some of those prescriptions, however, may be going to women who don't benefit from the second six months of use, the study found.

The researchers, led by Helena Earl, a professor of clinical cancer care at the University of Cambridge in the UK, followed 4,089 women with early-stage tumors that were fuelled by the HER-2 protein, which is found in about 20 per cent of all breast cancers. In both the six- and 12-month groups, about 90 per cent of women were cancer-free after four years. Herceptin, known chemically as trastuzumab, "is one of the most successful precision medicines of our time", Ms Earl said.

"Reducing trastuzumab treatments so that patients can receive six months when that duration is effective for them will be an important part of what I would term personalising this targeted treatment."

"It's not as glamorous or sexy as the more-often looked at questions of targeting a mutation or an abnormality in the cancer with a targeted therapy," Ms Earl said. "But it does fit in."

Unlike studies done to get a new drug approved, which are typically conducted and paid for by industry, Ms Earl's research was funded by the UK's National Institute for Health Research. It is the largest study yet conducted into shortening the duration of Herceptin's use.

In 2012, research funded by Roche found extending the treatment to two years didn't boost the benefit, while an independent French study on six months of treatment yielded inconclusive results.

"Many, many people in the field have been looking at the question over a number of years, and these data will need to be viewed in the context of that larger group," Roche chief medical officer Sandra Horning said in an interview.

"It's a really important question because you are talking about the potential to cure patients and essentially save their lives. Everybody wants to be really careful, conscientious and thorough in evaluating any new data set that comes along in this potentially curative setting."

The cost of treating women with Herceptin is already poised to drop as the drug faces competition in Europe from cheaper copycats known in the industry as biosimilars.

Pfizer Inc is among the companies seeking approval to sell a version in the US. The researchers are still in the initial stages of analysing the results and plan additional work on issues like the women's quality of life and the impact on cost, Ms Earl said. BLOOMBERG