Enhertu Demonstrates Superior Efficacy in Early Breast Cancer Treatment

AstraZeneca and Daiichi Sankyo's antibody-drug conjugate (ADC) Enhertu has achieved another significant milestone in the treatment of early breast cancer, outperforming Roche's Kadcyla in a pivotal phase 3 trial. The results position Enhertu as a potential foundational treatment option in the curative-intent setting for early breast cancer patients.

Destiny-Breast05 Trial Results

The Destiny-Breast05 trial, involving 1,635 patients with HER2-positive early breast cancer at high risk of recurrence, demonstrated Enhertu's superiority over Kadcyla. Patients in the study had residual invasive disease in the breast or axillary lymph nodes following neoadjuvant treatment.

At an interim analysis, Enhertu showed a "highly statistically significant and clinically meaningful improvement" in invasive disease-free survival (IDFS) compared to Kadcyla. Dr. Susan Galbraith, AstraZeneca's Head of Oncology Hematology R&D, stated, "This landmark trial is the first to directly compare Enhertu and T-DM1 in early breast cancer and the results clearly show that Enhertu delivers superior outcomes."

Expanding Enhertu's Potential

The success in Destiny-Breast05 follows another recent win for Enhertu in the Destiny-Breast11 trial, where it outperformed the standard of care as a presurgical treatment for high-risk, locally advanced HER2-positive early breast cancer. These combined results underscore AstraZeneca and Daiichi Sankyo's commitment to advancing Enhertu's use in early-stage HER2-positive breast cancer.

The companies plan to present data from both studies at the upcoming 2025 European Society for Medical Oncology (ESMO) Congress and will share results from Destiny-Breast05 with global regulatory authorities.

Implications for Breast Cancer Treatment

Breast cancer remains the second most common cancer worldwide, with approximately half of HER2-positive early breast cancer patients experiencing residual disease following neoadjuvant treatment. This residual disease increases the risk of recurrence, highlighting the need for more effective therapies in the early setting to prevent progression to metastatic disease.

Enhertu's success in early breast cancer builds upon its existing approvals across six indications since its initial approval in 2019 for third-line treatment of HER2-positive breast cancer. The drug generated sales of $3.75 billion in 2024, reflecting its growing importance in the oncology market.