PracticeUpdate: Oncology - Winter 2018

ASCO 2018 29

Shorter Trastuzumab Treatment for HER2– Positive Breast Cancer Can Be as Effective, With Fewer Cardiac Side Effects By the PracticeUpdate Editorial Team

Taking trastuzumab for 6 months has been shown to be noninferior to the standard of 12 months. The rate of disease-free survival rate after 4 years was 89.4% with 6 months and 89.8% with 12 months of therapy. In addition, only 4% of women in the 6-month arm stopped trastuzumab early because of cardiac toxicity versus 8% in the 12-month arm. T his outcome of the phase III randomized PERSEPHONE clinical trial of 4088 women with HER2-positive, early-stage breast cancer was Dr. Earl said in an ASCO press release, “Researchers in the PERSEPHONE trial worked closely with patient advocates. Everyone involved in PERSEPHONE is very excited by these results. We are confident that these results will mark the first steps toward a reduction of the duration of trastuzumab treatment to 6 months in many women with HER2-positive breast cancer.”

reported at ASCO 2018. Helena Earl, MD, of the University of Cambridge, United Kingdom, explained that PERSEPHONE was the largest trial to examine the impact of shortening the duration of trastuzumab treatment. In PERSEPHONE, half of the women took trastu- zumab for 6 months, and the other half took it for 12 months. Women also received chemotherapy (anthra- cycline-based, taxane-based, or a combination of both). The noninferiority design allowed for determination of whether reduced duration of treatment can be as effective as the standard treatment within prespeci- fied limits. Women were followed for a median of more than 5 years. A total of 89.4% of women in the 6-month arm and 89.8% in the 12-month arm were alive and free of breast cancer after 4 years. Overall, 6 months of tras- tuzumab treatment was noninferior to 12 months. Only 4% of women who received trastuzumab for 6 months stopped treatment early due to cardiac tox- icity versus 8% of those who took trastuzumab for 12 months. Trastuzumab was granted FDA approval based on the results of three major trials reported in 2005. In these trials, the length of trastuzumab treatment was 12 months, and this treatment length quickly became the standard of care. Shortly thereafter, the small FinHer trial in Finland reported similar benefit from as little as 9 weeks of trastuzumab therapy, prompting research interest in shortening treatment length to reduce side effects and cost.

Bruce E. Johnson, MD, of the Dana-Farber Cancer Insti- tute in Boston, Massachusetts, commented, “The use of trastuzumab has been a major advance for women with HER2-positive breast cancer by increasing the cure rate, but no treatment is free of side effects, and heart damage has always been a concern with this treatment.” He continued, “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 can- cer who are receiving this common treatment.” The researchers are analyzing the results to determine the impact of treatment length on quality of life, with qualitative feedback from trial participants. A detailed cost-effectiveness analysis is also underway. Dr. Earl stated that more research is needed to define particular patients for whom treatment duration can be reduced safely. They plan to analyze blood and tissue samples collected during the trial to seek biomarkers to identify specific risk groups. www.practiceupdate.com/c/69048 " We are confident that these results will mark the first steps toward a reduction of the duration of trastuzumab treatment to 6 months in many women with HER2-positive breast cancer. "

VOL. 2 • NO. 3 • 2018