Shorter Trastuzumab Regimen Okay in HER2+ Early Breast Cancer

NEW YORK (Reuters Health) - Women with HER2-positive early-stage breast cancer do just as well if they take adjuvant trastuzumab for six months rather than the current standard 12 months, according to a large phase 3 study.

"Everyone involved in this study is very excited by these results," Dr. Helena Earl, professor of clinical cancer medicine at the University of Cambridge in the U.K., said in a news release. "We are confident that this will mark the first steps towards a reduction of the duration of trastuzumab treatment to six months in many women with HER2-positive breast cancer."

"This new trial shows that a shorter length of treatment can benefit patients just as much as a longer treatment, with less risk of cardiac side effects. This is a win-win for patients with breast cancer who are receiving this common treatment," ASCO president Dr. Bruce Johnson said in the release.

Dr. Earl presented the findings from the Persephone trial May 16 at a press briefing ahead of presentation June 4 at the American Society of Clinical Oncology annual meeting in Chicago.

The trial included more than 4,000 women with HER2-positive early breast cancer. Half of the women took trastuzumab for six months and the other half for 12 months. The women also received standard chemotherapy (anthracycline-based, taxane-based, or a combination of both). They were followed for a median of more than five years.

At four years, the disease-free survival rate was virtually identical - 89.4% with six months of trastuzumab and 89.8% with 12 months. The calculated hazard ratio was 1.05 (95% confidence interval, 0.88 to 1.25) demonstrating non-inferiority of six months of trastuzumab, Dr. Earl told the briefing.

In addition, "six months compared with 12 month treatment reduces cardiac and other toxicities and costs both to patients and healthcare systems," she said, noting that 4% of women in the six-month arm stopped trastuzumab early due to cardiotoxicity compared with 8% in the 12-month arm (P<0.0001).

This is the largest trial to date examining the impact of shortening the duration of trastuzumab treatment, Dr. Earl noted. Given known cardiac and other toxicities during months seven to 12 of trastuzumab therapy, "our results would support a reduction of standard trastuzumab duration to six months," the researchers conclude in their meeting abstract.

Commenting on the findings at the briefing, Dr. Johnson noted that "12% of women have early-stage HER2-positive breast cancer. This is a very important study for helping our patients live longer and live better."

The study had no commercial funding. Several authors disclosed relationships with various pharmaceutical companies.


ASCO 2018 Annual Meeting.


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