Phase lb/ll study of the PI3Kα inhibitor BYL719 in combination with cetuximab in recurrent/metastatic squamous cell cancer of the head and neck (SCCHN).

6044 Background: Preclinical data suggest that simultaneous inhibition of PI3K and EGFR leads to synergistic antitumor activity in SCCHN. BYL719 is a potent, oral inhibitor of the α-isoform of class I PI3K. The Phase Ib dose-escalation part of this study used a Bayesian model to identify the recommended Phase II dose (RP2D) of BYL719 combined with standard weekly doses of cetuximab (EGFR inhibitor) in patients (pts) with platinum-resistant, recurrent/metastatic SCCHN (NCT01602315). Methods: BYL719 was administered QD in 28-day cycles using two methods: (1) as whole tablets (Arm A) or (2) as a drinkable suspension (crushed tablets) for pts with swallowing dysfunction (Arm B). Results: As of Oct 28, 2013, 32 pts were treated with either BYL719 300 mg QD (n=15) or 400 mg QD (n=5) in Arm A or BYL719 300 mg QD (n=12) in Arm B. At 300 mg (Arms A+B), 4 out of 27 pts had dose-limiting toxicities (DLTs; 2 mucositis, 1 hyperglycemia, and 1 PEG tube site infection). At 400 mg (Arm A), 2 out of 5 pts had DLTs (1 fata...