Docetaxel-PM Plus Trastuzumab Biosimilar Showed Antitumor Activity Among Patients With HER2-Positive Salivary Duct Carcinoma

According to a phase 2 trial, the combination of docetaxel-polymeric micelle (PM) and the trastuzumab biosimilar, trastruzumab-pkrb, demonstrated promising antitumor activity, with a manageable toxicity profile, among patients with HER2-positive advanced salivary duct carcinoma.

Study authors wrote, salivary duct carcinoma “shares morphological and histological similarities with invasive ductal carcinoma of breast, which led to an investigation of hormonal receptor and human epidermal growth factor 2 (HER2)/neu expression status in [salivary duct carcinoma].”

This multicenter, single-arm, open-label, phase 2 trial enrolled 43 patients with HER2-positive advanced salivary duct carcinomas. Patients were treated with 75 mg/m2 docetaxel-PM and 8 mg/kg in cycle 1 and 6 mg/kg in subsequent cycles of trastuzumab-pkrb every 3 weeks. The primary end point of the trial was objective response rate.

The best objective responses were partial responses, observed in 30 patients (69.8%) and stable disease in 10 patients (23.3%). This represented an objective response rate of 69.8% and a disease control rate of 93.0%. The median progression-free survival was 7.9 months, the median duration of response was 6.7 months, and the median overall survival was 23.3 months. Those patients with a HER2 immunohistochemistry (IHC) score of 3+ or HER2/chromosome enumeration probe w7 (CEP17) ratio ≥ 2.0 experienced better efficacy than those with HER2 IHC scores of 2+.

There were 38 patients (88.4%) who experienced a treatment-related adverse event. In 20.9%, 32.6%, and 44.2% of patients, treatment-related adverse events led to temporary discontinuation, permanent discontinuation, or dose reduction, respectively.

Study authors concluded, “The combination of docetaxel-PM and trastuzumab-pkrb demonstrated promising antitumor activity with a manageable toxicity profile in HER2-positive advanced [salivary duct carcinoma].”

Source:

Lee J, Park S, Jung HA, et al. A phase 2 multicenter study of docetaxel-PM and trastuzumab-pkrb combination therapy in recurrent or metastatic salivary gland carcinomas. Cancer. Published online May 28, 2023. doi:10.1002/cncr.34892