Inclusion Criteria:

          -  Criteria for the Phase 1b:

               -  Patients with locally advanced or metastatic solid tumors who have either
                  relapsed following, or progressed through, standard therapy; have a current
                  disease state for which there is no standard effective therapy; is not a
                  candidate for, or is unwilling to undergo, standard therapy in cases where no
                  curative option exists.

          -  Cohort-specific criteria for Phase 2:

               -  CRC (Colorectal cancer): Patients with metastatic CRC and known KRAS (Kirsten rat
                  sarcoma viral oncogene homolog) status who are eligible for treatment with
                  regorafenib in accordance with the approved labeling.

               -  NSCLC (Non-small-cell lung cancer): Patients with NSCLC and known KRAS status
                  after platinum based chemotherapy.

               -  Breast cancer: Patients with Her-2 negative breast cancer after anthracycline and
                  taxane based chemotherapy.

          -  Baseline tumor tissue to conduct molecular and / or genetic studies should be
             available from all study patients enrolled in this study. (optional in Phase 1b)

          -  Patients must have at least one uni-dimensional measurable lesion by CT or MRI
             according to Response Evaluation Criteria in Solid Tumors (RECIST)version 1.1.
             (applicable only in Phase 2)

          -  Male or female patients ≥ 18 years of age (only female patients in breast cancer
             cohort of Phase 2).

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status of 0 or 1

          -  Life expectancy of at least 3 months

          -  Adequate bone marrow, liver and renal function

          -  Cardiac function within normal range

        Exclusion Criteria:

          -  Prior treatment with refametinib or regorafenib.

          -  Metastatic brain or meningeal tumors

          -  Uncontrolled hypertension despite optimal medical management

          -  History of cardiac disease

          -  Arterial or venous thrombotic or embolic events

          -  Any hemorrhage or bleeding event

          -  History or current evidence of retinal vein occlusion (RVO) or central serous
             retinopathy (CSR).

          -  Any condition that was unstable or which could jeopardize the safety of the patient
             and his/her compliance in the study.

          -  Excluded previous therapies and medications:

               -  Radiotherapy within 3 weeks prior to start of treatment

               -  Systemic anticancer therapy including cytotoxic therapy, signal transduction
                  inhibitors, immunotherapy, and hormonal therapy during this trial or within 28
                  days or 5 drug half-lives (if drug half-life in patients is known), whichever is
                  shorter (or within 6 weeks for mitomycin C) before start of the study treatment