BCRF-supported clinical trial signals long-term efficacy of reducing chemotherapy in some patients with HER2-positive breast cancer
Key Takeaways
- Results from a phase 2 clinical trial study supported by the Breast Cancer Research Foundation showed that a shorter treatment regimen was effective for some women with HER2-positive breast cancer.
- The abbreviated treatment regimen reduces the duration and intensity of chemotherapy.
- The DAPHNe trial also showed that circulating tumor DNA (ctDNA) may effectively measure treatment response.
A recent Breast Cancer Research Foundation (BCRF)-supported phase 2 clinical trial, DAPHNe, found that an abbreviated treatment regimen for non-metastatic HER2-positive breast cancer showed excellent outcomes after five years, and follow-up tests showed that nearly all patients had no circulating tumor DNA (ctDNA).
The National Comprehensive Cancer Network guidelines currently recommend the standard-of-care Taxane, Herceptin, and Perjeta (THP) regimen (paclitaxel, trastuzumab, and pertuzumab) for 18-24 weeks. Taxane is a chemotherapy drug and Herceptin and Perjeta are HER2-targeted monoclonal antibodies. However, focus has gradually shifted to developing better-tolerated breast cancer treatments through shortening the duration and reducing the intensity of traditional chemotherapy strategies.
The recent findings from the DAPHNe phase 2 clinical trial suggest that favorable outcomes may be achieved with a shorter (12 weeks), reduced regimen. DAPHNe demonstrated outstanding five-year outcomes with THP for 12 weeks in a group in which most patients had stage 2 HER2-positive breast cancer.
More than half of the patients in the primary trial analysis achieved a pathologic complete response (pCR) at surgery, meaning that after the treatment, there were no signs of cancerous cells found in patients’ tissue samples removed during surgery. Patients were then moved to antibody-only adjuvant therapy. About 99% of these patients achieved five-year event-free survival and overall survival without further adjuvant chemotherapy.
“The DAPHNe study, and others, are paving the way to the reduced use of chemotherapy in non-metastatic HER2 positive breast cancer,” says Dr. Eric Winer, BCRF SAB Chair and a co-author on the study. “As biologic therapy has improved, it looks like we will be able to use less and less chemotherapy. Clinical trials are critical in moving this approach forward.”
DAPHNe also evaluated whether ctDNA could predict treatment response. Investigators demonstrated that ctDNA analyses yielded near-universal clearance after abbreviated neoadjuvant therapy, supporting further investigation of strategies that reduce chemotherapy.
Tracking ctDNA may be a promising strategy for measuring treatment response, and further research will give us more insight into what ctDNA can tell us and how best to leverage the information. More research into strategies that limit chemotherapy may also provide more breast cancer patients with newer, less harsh treatment regimens.
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