Inclusion Criteria:

          -  Male or female aged ≥ 18 years

          -  Histological or cytological confirmed metastatic colorectal cancer

          -  Written documentation of KRAS wild-type status and BRAFV600-mutation with RNF43
             mutation and/or RSPO fusion

          -  Progression of disease after at least one prior standard of care regimen or intolerant
             to irinotecan based regimens

          -  Availability of a representative tumor specimen (primary or metastatic, archival or
             newly obtained)

          -  Measurable disease as per RECIST v1.1

          -  Eastern cooperative oncology group (ECOG) performance status ≤ 2

        Exclusion Criteria:

          -  Phase II only: Prior treatment with RAF inhibitors, Wnt pathway inhibitors, cetuximab,
             panitumumab, and/or other EGFR inhibitors

          -  Symptomatic brain metastasis. Patients previously treated or untreated for these
             conditions that are asymptomatic in the absence of corticosteroid and anti-epileptic
             therapy are allowed to enroll

          -  Current treatment with medications or consuming foods that are strong inhibitors or
             inducers of CYP3A4/5 or herbal medications and that cannot be discontinued at least
             one week prior to the start of treatment.

          -  Symptomatic or untreated leptomeningeal disease

          -  Acute or chronic pancreatitis

          -  Clinically significant cardiac disease

          -  Patients with any of the following laboratory values at Screening/baseline

               -  Absolute neutrophil count (ANC) <1,500/mm3

               -  Platelets < 100,000/mm3

               -  Hemoglobin < 9.0 g/dL

               -  Serum creatinine >1.5 x ULN or calculated or directly measured CrCl < 50% lower
                  limit of normal

               -  Serum total bilirubin >1.5 x ULN

               -  AST/SGOT and/or ALT/SGPT > 2.5 x ULN, (> 5 x ULN if liver metastases present)

          -  Patients with impaired hepatic function as defined by Childs-Pugh class B or C

          -  Impairment of gastrointestinal (GI) function or GI disease that may significantly
             alter the absorption of oral WNT974/LGX818

        Other protocol-defined inclusion/exclusion criteria may apply