1166P - Combined androgen blockade in patients with advanced androgen receptor-positive salivary gland carcinoma: Exploratory biomarker analyses

A phase II trial of combined androgen blockade (CAB) in patients with advanced androgen receptor (AR)–positive salivary gland carcinoma (SGC) showed 40% of the overall response rate. However, biomarkers which predict survival in this population remain unknown. A total of 99 patients with AR–positive SGC treated with leuprorelin acetate plus bicalutamide were included. Age, sex, ECOG performance status (PS), previous treatment with trastuzumab plus docetaxel, modified Glasgow Prognosis Score (mGPS), neutrocyte-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), serum C-reactive protein (CRP) and testosterone level, HER2 status (according to ASCO/CAP Guidelines), mutational status of BRAF, PIK3CA, HRAS, AKT1 and TP53, immunohistochemistry (IHC) score of AR, Ki-67, CK5/6, p53, HER3, Akt, PI3K, FOXA1, adipophilin, mTOR and PTEN were assessed and correlated with progression-free survival (PFS) and overall survival (OS). Female sex, mGPS (1 or 2 vs. 0), NLR (≥4.48), PLR (≥234.27), and Ki-67 labeling index (≥ 40%) were significantly associated with shorter PFS (hazard ratio [HR], 3.57, 2.01, 1.76, 1.62, and 2.16, respectively) and OS (HR, 4.91, 4.98, 3.10, 2.95, and 1.78, respectively). IHC scores of PTEN (3+) and adipophilin (≥5%) were related with favorable PFS (HR, 0.57 and 0.49, respectively) and OS (HR, 0.48 and 0.42, respectively). Age, ECOG PS, CRP, testosterone, AR positive ratio (≥70% or