Enhertu Combination Shows Promise in First-Line HER2-Positive Breast Cancer Treatment

AstraZeneca and Daiichi Sankyo have announced promising results from a Phase 3 trial evaluating a combination therapy involving Enhertu (trastuzumab deruxtecan) for the treatment of HER2-positive breast cancer. The study, which compared Enhertu plus pertuzumab to the current standard of care, demonstrated significant improvements in progression-free survival for patients with metastatic disease.

Enhertu Regimen Outperforms Standard Therapy

The large-scale trial enrolled 1,157 patients newly diagnosed with advanced HER2-positive breast cancer. Participants were randomized to receive either the Enhertu-pertuzumab combination or the current standard therapy known as THP (taxane, trastuzumab, and pertuzumab).

Results showed that the Enhertu regimen significantly outperformed THP in terms of progression-free survival, with benefits observed across all patient subgroups. While specific data were not disclosed, the companies reported a "highly statistically significant and clinically meaningful effect" on this primary endpoint.

Moreover, an early trend suggests a potential survival benefit for patients receiving the Enhertu combination, although longer follow-up is needed to confirm this finding. The safety profile of the new regimen was consistent with previous observations for the individual components.

Potential Paradigm Shift in First-Line Treatment

The success of this trial could mark a significant milestone in the treatment of HER2-positive breast cancer, which accounts for approximately 15-20% of all breast cancers. If approved for first-line use, the Enhertu-pertuzumab combination would be the first regimen in over a decade to surpass the efficacy of the current standard of care.

Susan Galbraith, AstraZeneca's Executive Vice President of Oncology and Hematology Research and Development, emphasized the importance of these results, stating, "This is a significant milestone for patients and sets the foundation for Enhertu in combination with pertuzumab as an important treatment option in the first-line HER2-positive setting."

The potential expansion into first-line therapy aligns with AstraZeneca and Daiichi Sankyo's strategy to position antibody-drug conjugates (ADCs) like Enhertu for earlier and broader use in cancer treatment. This approach has already seen success, with Enhertu recently gaining approval for use before chemotherapy in patients with low but detectable HER2 levels.

As the pharmaceutical industry awaits more detailed data from this trial, to be presented at a future medical meeting, the results underscore the ongoing evolution of targeted therapies in oncology and the potential for improved outcomes in patients with HER2-positive breast cancer.