Enhertu Breakthrough: AstraZeneca and Daiichi Sankyo's ADC Shows Survival Benefit in Stomach Cancer

AstraZeneca and Daiichi Sankyo have announced a significant milestone for their antibody-drug conjugate (ADC) Enhertu, marking a new chapter in the treatment of advanced stomach cancer. The drug has demonstrated a survival benefit in second-line metastatic stomach cancer, becoming the first HER2-directed therapy to achieve this feat in a randomized clinical trial.

Destiny-Gastric04 Trial Results

The phase 3 Destiny-Gastric04 study, which compared Enhertu to Eli Lilly's VEGFR inhibitor Cyramza and chemotherapy, showed a statistically significant and clinically meaningful improvement in overall survival for patients with previously treated HER2-positive unresectable or metastatic gastric or gastroesophageal junction adenocarcinoma. The trial's independent data monitoring committee recommended unblinding the study early due to the compelling results.

This latest success builds on Enhertu's previous approval by the FDA in 2021 for stomach cancer following prior treatment with a trastuzumab-based regimen. The earlier approval was based on the phase 2 Destiny-Gastric01 trial, which demonstrated a 41% reduction in the risk of death compared to chemotherapy alone in a third-line setting.

Expanding Global Reach and Future Directions

Enhertu currently holds stomach cancer approvals in over 65 countries. AstraZeneca and Daiichi Sankyo plan to leverage the Destiny-Gastric04 results to seek approvals in markets where Enhertu is not yet indicated as a second-line option or to secure full approvals where the drug is only conditionally approved.

The companies are not resting on their laurels, having recently launched the four-arm phase 3 Destiny-Gastric05 trial to evaluate Enhertu as a first-line treatment for HER2-positive stomach cancer. This study is expected to reach primary completion in 2028, potentially expanding Enhertu's role in the treatment paradigm for gastric cancer.

Enhertu's Growing Impact in Oncology

Since its initial FDA approval in 2019, Enhertu has consistently broken new ground in cancer treatment. Notable achievements include pioneering the HER2-low breast cancer category and receiving FDA approval for HER2-ultralow disease. In a landmark decision last year, the drug also gained a tumor-agnostic indication, allowing its use in patients with any HER2-positive tumors who have exhausted primary systemic treatments and have no satisfactory alternatives.

As Enhertu continues to demonstrate its efficacy across various cancer types and stages, it solidifies its position as a cornerstone therapy in the evolving landscape of targeted cancer treatments. The pharmaceutical industry watches closely as AstraZeneca and Daiichi Sankyo push the boundaries of what's possible in cancer care, potentially reshaping treatment strategies for patients with limited options.