Study of Safety & Efficacy of the Combination of LJM716 & BYL719 in Patients With Previously Treated Esophageal Squamous Cell Carcinoma (ESCC)

Inclusion Criteria:

* Histologically confirmed esophageal squamous cell carcinoma (ESCC)
* No more than one prior chemotherapy regimen for recurrent or metastatic ESCC (for Phase II only).
* Progression during or after platinum-based therapy for recurrent or metastatic ESCC, or recurrence within 6 months of platinum-based chemotherapy or chemoradiotherapy for localized disease.

Exclusion Criteria:

* Patients who received prior phosphoinositide-3-kinase (PI3K) inhibitor or anti-receptor tyrosine-protein kinase erbB-3 (ERBB3 or HER3) antibody treatment, including bi-specific antibodies with HER3 as one of the targets (patients with prior exposure to pertuzumab or epidermal growth factor receptor (EGFR)-targeted agents are eligible)
* Patients who do not have an archival or fresh tumor sample (or sections of it) available or readily obtainable.
* Patients with central nervous system (CNS) metastatic involvement.
* Patients who have received prior systemic anti-cancer treatment, such as cyclical chemotherapy or biological therapy within a period of time that is shorter than the cycle length used for that treatment (e.g. 6 weeks for nitrosourea, mitomycin-C) prior to starting study treatment.
* Patients who have received definitive radiotherapy ≤ 4 weeks prior to starting study drug, who have not recovered from side effects of such therapy and/or from whom ≥ 30% of the bone marrow was irradiated.
* Other protocol-defined inclusion/exclusion criteria may apply.