A Phase Ib/II Study of BYL719 and Cetuximab in Recurrent or Metastatic Head and Neck Squamous Cell Carcinoma

Inclusion Criteria:

* Age ≥ 18 years
* Patients with histologically/cytologically-confirmed HNSCC
* Patients must be resistant to platinum-based chemotherapy, or be ineligible (due to medical comorbidities) or intolerant to platinum-based therapy per medical history
* For Phase Ib, there is no restriction on the number of prior therapies for recurrent or metastatic disease
* For Phase II, patients may have received a maximum of 1 prior line of therapy for recurrent or metastatic disease
* For Phase Ib, prior cetuximab or other EGFR-targeted antibody therapy is allowed regardless of the prior treatment settings.
* For Phase II, Arms 1 and 2, prior cetuximab or other EGFR-targeted antibody therapy is allowed only if administered in the induction setting, or concurrently with radiation in the curative setting, with the last dose of cetuximab administered at least 12 months prior to starting the study treatment. For Arm 3, prior cetuximab must have been administered in the curative, recurrent or metastatic disease setting and disease progression documented within 9 months of the last dose of cetuximab administered in that setting. This regimen (including both platinum and cetuximab) must be the most recent anti-neoplastic treatment regimen administered.
* Patients with swallowing dysfunction who are unable to swallow BYL719 whole tablets and are not using feeding tubes for study drug administration can participate in the Phase Ib Arm B. For the Phase II, these patients with swallowing dysfunction may participate if able to drink the suspension and results of Arm B confirm the use of this method. Patients with swallowing dysfunction requiring G tube (G/PEG tube) for study drug administration may participate in Phase II if Arm C confirms dispersible tablet via G tube administration is permitted if the administration of drinkable suspension of BYL719 is allowed to be used in Phase II.
* Availability of a representative tumor specimen. Patients enrolled in Arm 3 of Phase II must have disease sites amenable to biopsy unless prior agreement between Novartis and the Investigator.
* At least one measurable or non-measurable lesion as per RECIST 1.1 criteria for patients in Phase Ib; Measurable disease as determined by RECIST v1.1 for Phase II patients
* World Health Organization (WHO) Performance Status (PS) ≤ 2
* Adequate organ function
* Negative serum pregnancy test.

Exclusion Criteria:

* Prior treatment with PI3K-inhibitors
* Patients with a prior serious infusion reaction to cetuximab
* Patients with uncontrolled CNS tumor metastatic involvement
* Clinically significant cardiac disease or impaired cardiac function
* Patients with diabetes mellitus
* Impaired GI function or GI disease
* History of another malignancy within 2 years prior to starting study treatment
* Pregnant or nursing (lactating) women