Long-duration trastuzumab remains standard of care in HER2-positive breast cancer
Click Here to Manage Email Alerts
Key takeaways:
- Short-duration trastuzumab did not show noninferiority to long-duration trastuzumab overall.
- Certain patients with low/intermediate HER2-positive disease may benefit from a shorter, 9-week course.
CHICAGO — One-year of adjuvant trastuzumab remains the standard-of-care treatment duration for most patients with HER2-positive early breast cancer, according to study results presented at ASCO Annual Meeting.
However, certain patients with low/intermediate HER2-positive early breast cancer may benefit from a shorter, 9-week course of trastuzumab (Herceptin, Genentech), researchers noted.
Background and methods
“We presented the primary endpoint of DFS during the 2017 ASCO meeting, which included 5.2 years of follow-up that showed 5-year DFS of 87.5% with long-duration trastuzumab vs. 85.4% with short-duration,” Pier Franco Conte, MD, professor of oncology in the department of surgery, oncology and gastroenterology at University of Padua and Veneto Institute of Oncology IOV-IRCCS in Italy, said during a presentation. “At the time, noninferiority could not be claimed because the upper limit of the confidence interval crossed the preset limit. However, according to a preplanned Bayesian analysis, the probability of the short-duration treatment was not inferior. In addition, the short-duration treatment was also associated with significantly lower cardiac toxicity.”
The Short-HER2 phase 3 trial compared short-duration (9 weeks) vs. long-duration (1 year) adjuvant trastuzumab plus chemotherapy among 1,254 patients (median age, 55 years; 54% node-negative; 30% with one to three positive nodes) with HER2-positive early breast cancer.
Conte presented final results of the second co-primary endpoint of OS, as well as DFS and OS according to nodal status.
Median follow-up was 9 years.
Findings
At the time of data cutoff, researchers reported 248 DFS events and 116 deaths.
Results showed a 10-year DFS rate of 77% with 1-year vs. 78% with 9-week adjuvant trastuzumab (HR = 1.06; 90% CI, 0.86-1.31).
Researchers also observed a 10-year OS rate of 89% with long-duration trastuzumab compared with 88% with short-duration trastuzumab (HR = 1.15; 90% CI, 0.85-1.56).
Those with node-negative disease had similar 10-year DFS rates with 1-year vs. 9-week adjuvant trastuzumab (81% vs. 85%; HR = 0.74; 90% CI, 0.54-1.04), and similar 10-year OS rates (89% vs. 95%; HR = 0.57; 90% CI, 0.33-0.99).
For patients with one to three positive lymph nodes, results showed a 10-year DFS rate of 77% with 1-year vs. 79% with 9-week adjuvant trastuzumab (HR = 1.11; 90% CI, 0.76-1.64), and 10-year OS rates of 92% vs. 89% (HR = 1.37; 90% CI, 0.77-2.44).
Those with four or more positive lymph nodes had a 10-year DFS rate of 63% with 1-year vs. 53% with 9-week adjuvant trastuzumab (HR = 1.84; 90% CI, 1.24-2.75), and 10-year OS rates of 84% vs. 64% (HR = 1.87; 90% CI, 1.11-3.14).
“Numerically, at median follow-up of 9 years, 10-year DFS and OS of long vs. short trastuzumab are quite close, but a stratified analysis suggests that patients with four or more positive nodes and stage III disease may have an advantage both in DFS and OS when treated with 1-year trastuzumab,” Conte said.
Implications
Noninferiority of short-duration trastuzumab cannot be claimed, so the long-duration treatment remains standard of care, according to Conte.
“However, 9-week trastuzumab may represent an affordable and effective option for patients with low or intermediate-risk, HER2-positive breast cancer living in countries where access to trastuzumab may be a problem,” he said.
Collapse
Conte PF, et al. Abstract LBA637. Presented at: ASCO Annual Meeting; June 2-6, 2023; Chicago.
Read more about
Click Here to Manage Email Alerts