BERLIN — A novel antibody drug conjugate (ADC) targeting HER3 (ERBB3) increases antitumor activity in patients with early-stage hormone receptor (HR)-positive/HER2-negative breast cancer after just one dose, according to the results of an early phase study.
The analysis revealed that patritumab deruxtecan (HER3-DXd, Daiichi Sankyo) was associated with a significant increase in tumor cellularity and tumor-infiltrating lymphocyte (CelTIL) scores and demonstrated an overall response rate of 45% in patients with untreated, early-stage disease.
Aleix Prat, MD, PhD, head of the Medical Oncology Department of Hospital Clínic Barcelona, Spain, presented findings from the SOLTI TOT-HER3 trial at the European Society for Medical Oncology (ESMO) Breast Cancer Congress 2022 on May 3.
Patritumab deruxtecan recently received Breakthrough Therapy Designation from the US Food and Drug Administration to treat metastatic or locally advanced EGFR-mutated non-small cell lung cancer with disease progression on or after prior treatment.
In breast cancer, patritumab deruxtecan has also demonstrated antitumor activity and an acceptable safety profile in heavily pretreated patients with metastatic disease and varying levels of HER3 protein expression.
In addition, interim results from the SOLTI TOT-HER3 trial in 30 patients with early-stage HR-positive/HER2-negative breast cancer reported biologic and clinical activity from a single dose of the drug.
