Drug-based therapy for advanced adenoid cystic carcinoma: Current landscape and challenges based on an overview of registered clinical trials

Adenoid cystic carcinoma (ACC) has a significant patient-population in need of effective systemic therapy, as no drug is currently approved by the FDA for its management. We critically reviewed ACC-clinical trials (CT) registered on the ClinicalTrials.gov website using "ACC" under condition or disease. Trials specifically designed to test a drug-based therapy for ACC (n = 33) were analyzed with most being one-arm phase II trials enrolling advanced, recurrent/metastatic, incurable ACC cases. Site restriction, maximum ECOG status, and period of disease progression varied as inclusion criteria. Small-molecule inhibitors were those most commonly investigated with Apatinib, Axitinib and Lenvatinib showing the best results in association with rigid enrollment criteria. The overall median time to progression remains modest and more efforts are urgently needed in this field. CTs designed to test drugs that act on key pathways associated with ACC aggressiveness are being conducted and represent a promising pathway if efficacy is proved.