AstraZeneca (AZ) and Daiichi Sankyo’s antibody drug conjugate (ACD) datopotamab deruxtecan has demonstrated 'promising' preliminary response and disease control in new data evaluating the therapy among patients with metastatic triple negative breast cancer (TNBC).

The preliminary data, presented at the 2021 European Society of Medical Oncology (ESMO) Breast Cancer virtual congress, comes from the TNBC cohort of AZ/Daiichi’s TROPION-PanTumor01 Phase I study.

Patients in this study had previously received treatment with a median of four prior lines of therapy, with 88% of these patients having received more than two previous lines of treatment.

In this study, the preliminary objective response rate (ORR) was 43% in 21 evaluable patients treated with the TROP2-directed ADC. Meanwhile, researchers observed five confirmed complete or partial responses (CR/PRs), with an additional four CR/PRs awaiting confirmation at the time of the data cut-off.

In addition, a disease control rate of 95% was observed in this early-stage trial, with the safety profile of datopotamab deruxtecan in the TNBC cohort found to be ‘consistent’ with the previously reported safety in the non-small cell lung cancer (NSCLC) cohort of the study.

As of the data cut-off, 75% of patients remained on treatment with datopotamab deruxtecan, AZ and Daiichi added in a statement.

“These preliminary results provide proof-of-concept that targeting TROP2 with datopotamab deruxtecan may be an effective treatment strategy for patients with previously treated metastatic triple negative breast cancer,” said Gilles Gallant, senior vice president, global head, oncology development, oncology R&D, Daiichi Sankyo.

“We are encouraged by the early tumour responses and disease control seen in these patients and we will continue to explore the potential of datopotamab deruxtecan in several types of breast cancer, including triple negative breast cancer,” he added.

TNBC, which is associated with a higher disease recurrence and often a poorer prognosis compared to other breast cancer subtypes, makes up approximately 10-15% of breast cancer cases.

Estimates give only 12.2% of patients with metastatic TNBC a five-year survival rate, with median overall survival typically being less than two years.