The trial involved patients who were suffering from HER2 positive unresectable and / or metastatic breast cancer and received prior trastuzumab emtansine (T-DM1) treatment.
According to the top-line results, the trial met its primary endpoint of objective response rate, with the study drug demonstrating clinically meaningful response.
The safety and tolerability profile of the drug was also found to be consistent with previous data.
Trastuzumab deruxtecan is an antibody drug conjugate (ADC) developed for targeted delivery of chemotherapy inside cancer cells to minimise systemic exposure compared to the standard delivery.
The open-label, global, multi-centre, two-part trial assessed the safety and efficacy of the therapeutic in a total of 253 patients at more than 100 centres in North America, Europe, Japan and other Asian countries.
Its first part comprised a pharmacokinetic and a dose-finding stage to determine the recommended dose to be studied in the second part. The initial part identified an optimal dose of 5.4mg/kg.
These latest results are from the second part that assessed the optimal dose in patients who have failed or discontinued previous treatment with T-DM1.
The second part involved two cohorts – patients resistant or refractory to T-DM1 (part 2a) and those who discontinued T-DM1 therapy for reasons other than resistant or refractory disease (part 2b).
These findings are expected to support global regulatory submissions of the therapeutic.
AstraZeneca R&D Oncology executive vice-president and president José Baselga said: “We are encouraged to see positive data from [fam-] 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.”
Trastuzumab deruxtecan is being developed for the treatment of HER2 expressing tumours, including breast and gastric cancers.