Enhertu, Herceptin, and Perjeta Before Surgery for HER2-Positive Breast Cancer

Although early-stage HER2-positive breast cancer is highly treatable, inadequate treatment responses and disease recurrence remain serious problems for some patients. Neoadjuvant (preoperative) treatment that achieves a pathological complete response (pCR) is considered one of the strongest predictors of long-term survival. Optimizing treatment protocols to increase pCR rates is therefore critical to improving patients' chances of a cure.

This is precisely where the DESTINY-Breast11 trial highlights the potential of fam-trastuzumab deruxtecan-nxki (T-DXd, marketed as Enhertu) as neoadjuvant treatment for early-stage HER2-positive breast cancer.

Trial Summary: A Significant Increase in pCR With T-DXd + THP

Early findings announced by AstraZeneca from the phase 3 DESTINY-Breast11 trial indicate that treatment beginning with T-DXd, followed by a taxane (paclitaxel), trastuzumab (Herceptin), and pertuzumab (Perjeta) as the THP regimen , produced, compared with the standard dose-dense anthracycline (ddAC) + THP protocol, a statistically significantly higher pathological complete response (pCR) rate.

• 📊 Primary Endpoint:

  • The pCR ratewas markedly higher in the T-DXd + THP group.

• 📈 Secondary Endpoints:

  • Although event-free survival (EFS), invasive disease-free survival (IDFS), and overall survival (OS) data remain immature, EFS showed a favorable trend with T-DXd .

The Safety Profile of T-DXd: No New Adverse-Event Signals

When treatment-related adverse events were evaluated, the T-DXd + THP combination was consistent with the known safety profiles. In particular, interstitial lung disease (ILD) incidence was similar in both arms. This stands out as an important finding supporting the safety of the treatment.

Patient Selection and Trial Design

Patients included in the trial were:

• Aged 18 years or older,

• Diagnosed histologically with early-stage HER2-positive breast cancer,

• Had an ECOG performance status of 0–1,

• And had a left ventricular ejection fraction of ≥50%.

Exclusion criteria included a history of invasive breast cancer, stage 4 disease, another malignancy within 3 years, a history of systemic treatment, or previous ILD.

Scientific and Clinical Significance

As Dr. Susan Galbraith, Executive Vice President of Oncology-Hematology R&D at AstraZeneca, stated:

The clinically meaningful improvement in pCR and the safety data in this trial suggest that T-DXd could offer an option that challenges the standard of care for early-stage HER2-positive breast cancer.

Dr. Ken Takeshita, Global Head of Research and Development at Daiichi Sankyo, added:

Patients with early-stage disease who do not achieve a pCR in the neoadjuvant setting remain at risk of recurrence. New combinations such as T-DXd + THP therefore represent exciting treatment alternatives that could put patients on a path toward a cure.”

What Is T-DXd?

T-DXd is developed by Daiichi Sankyo and jointly studied with AstraZeneca, and is a HER2-targeted antibody-drug conjugate (ADC) that carries chemotherapy . It is already FDA-approved for metastatic breast cancer and various other HER2-positive tumors. The DESTINY-Breast11 data suggest that this drug could move into the early-stage setting .

Conclusion: A Turning Point That Could Change Standards?

The results of DESTINY-Breast11 have the potential to reshape neoadjuvant treatment algorithms for early-stage HER2-positive breast cancer. The T-DXd + THP combination not only achieves higher pCR rates but also shows promise in terms of safety. Complete EFS and OS data will clarify the future role of this combination, but already the door to T-DXd in early-stage disease has begun to open.