Human epidermal receptor 2-amplified salivary duct carcinoma: Regression with dual human epidermal receptor 2 inhibition and anti-vascular endothelial growth factor combination treatment

Background. Salivary ductal carcinoma is a rare cancer with poor prognosis and limited treatment options. Human epidermal receptor 2 (HER2)-directed treatment has been attempted in HER2-amplified or overexpressed salivary gland malignancies with limited success. Methods. We report resolution of measurable disease and minimal residual disease in a patient with salivary duct cancer treated with trastuzumab, lapatinib, and bevacizumab, with treatment ongoing for more than 2 years. Results. This treatment has been tolerated well except for grade 2 diarrhea and mucositis, which required a dose reduction of lapatinib to 1000 mg daily. The response observed was achieved in spite of receiving extensive prior therapy, including trastuzumab and/or chemotherapy for 20 months on which his tumors progressed. Conclusion. The combination of trastuzumab, lapatinib, and bevacizumab may warrant investigation as a non-cytotoxic alternative for treatment of HER2-amplified or overexpressed salivary duct carcinoma and other HER2-amplified or overexpressed salivary gland tumors, particularly those not responsive to trastuzumab monotherapy.