AstraZeneca reports positive findings from breast cancer threatment trial

New high-level results from AstraZeneca's TROPION-Breast01 phase three trial, released on Friday, carried encouraging news for patients with inoperable or metastatic hormone receptor (HR)-positive, HER2-low or negative breast cancer.

The FTSE 100 pharmaceuticals giant said the trial showed that the drug datopotamab deruxtecan (Dato-DXd) achieved a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared to traditional chemotherapy.

It further indicated a favourable overall survival (OS) rate trend for patients treated with datopotamab deruxtecan over chemotherapy.

However, the OS data was still in its interim phase and would need more time for conclusive results.

Therefore, AstraZeneca said the trial would proceed as scheduled to assess overall survival rates further.

Additionally, the drug's safety profile remained consistent with prior clinical trials conducted for breast cancer.

Importantly, no new safety issues were identified, and all-grade interstitial lung disease rates were low.

Datopotamab deruxtecan, a specially designed TROP2-directed DXd antibody-drug conjugate (ADC), is the collaborative effort of AstraZeneca and Daiichi Sankyo.

TROP2 is a protein found in high levels in HR-positive, HER2-low or negative breast cancer, a subtype accounting for over 65% of all breast cancer diagnoses globally.

More than two million people worldwide are diagnosed with breast cancer each year.

Although endocrine therapy is the standard treatment for HR-positive, HER2-low or negative breast cancer, many patients with advanced stages of the disease develop resistance, emphasising the need for alternative therapies.

AstraZeneca said the promising results would be presented at an upcoming medical conference and discussed with health authorities for potential implications in the treatment landscape.

In addition to TROPION-Breast01, AstraZeneca and Daiichi Sankyo are currently engaged in two other phase three trials examining the effectiveness of datopotamab deruxtecan in breast cancer.

TROPION-Breast02 aims to compare the drug with chemotherapy in patients with untreated locally recurrent inoperable or metastatic triple-negative breast cancer.

Meanwhile, TROPION-Breast03 will assess datopotamab deruxtecan's performance, both with and without Imfinzi (durvalumab), against other treatment options for patients with early to intermediate stages of triple-negative breast cancer with residual disease post neoadjuvant therapy.

“Today's TROPION-Breast01 news is a significant development for patients with HR-positive, HER2-low or negative metastatic breast cancer whose tumours have become insensitive to endocrine therapy and who currently face poor outcomes,” said Susan Galbraith, AstraZeneca’s executive vice-president of oncology research and development.

“We are encouraged by these positive results.”

At 0849 BST, shares in AstraZeneca were up 1.65% at 11,066p.

Reporting by Josh White for Sharecast.com.