AstraZeneca has announced that its joint HER2-targeting antibody drug conjugate (ADC) with Daiichi Sankyo has met its primary endpoint in a phase II trial.

The top-line results for its pivotal Phase II DESTINY-Breast01 trial of DS-8201 (trastuzumab deruxtecan) showed clinically-meaningful response and a consistent safety and tolerability profile, with results expected to support planned global regulatory submissions, including a Biologics License Application with the US Food and Drug Administration (FDA) anticipated in the second half of 2019.

Approximately one in five breast cancers are HER2-positive, meaning there is an unmet need for treatments. The experimental drug works by targeting the HER2 protein, a major trigger of uncontrolled cell growth in about 20% of breast cancers.

A recent publication in The Lancet Oncology reported long-term Phase I safety and preliminary efficacy results in HER2-positive metastatic breast cancer. This potential new medicine is currently in development for the treatment of multiple HER2-expressing cancers, including in patients with HER2-low expression.

José Baselga, executive vice president, R&D Oncology, said: “We are encouraged to see positive data from trastuzumab deruxtecan, with the DESTINY-Breast01 trial now reinforcing what earlier data have shown. We believe this antibody drug conjugate has the potential to redefine the treatment of patients with HER2-expressing cancers, and we are eager to bring it as quickly as possible to patients with refractory HER2-positive breast cancer who continue to have high unmet medical need.”

The drug has also been granted US FDA Breakthrough Therapy Designation and Fast Track Designation for HER2-positive patients in the advanced or refractory breast cancer setting.