Inclusion Criteria:

          -  For dose escalation cohorts: Subjects with advanced, histologically or cytologically
             confirmed solid tumors are eligible. Subjects' tumors (all comers) must be refractory
             to standard treatment with no standard therapy available, or subjects actively refuse
             any treatment, which would be regarded standard. In addition, the investigator must
             judge the experimental treatment as clinically and ethically acceptable

          -  For expansion cohort only: Subjects with histologically or cytologically proven
             metastatic breast cancer (with and without AKT1 E17K (G49A) mutation) or subjects with
             known AKT1 E17K (G49A) mutation in any other advanced solid tumor with at least one
             line of chemotherapy in the metastatic setting and not amenable to surgery with
             curative intent

          -  Subjects must have measurable disease (Response evaluation criteria in solid tumors
             (RECIST 1.1)

          -  Eastern Cooperative Oncology Group (ECOG) Performance Status 0 - 2

          -  Bone marrow, liver and renal functions as assessed by adequate laboratory methods to
             be conducted within 7 days prior to starting study treatment

          -  Subjects must provide tumor biopsies before treatment

          -  Recovery to CTCAE (Common Terminology Criteria for Adverse Events Version 4.03) Grade
             0 or Grade 1 or recovery to baseline preceding the prior treatment of any previous
             drug / procedure-related toxicity (except alopecia, anemia, and hypothyroidism)

        Exclusion Criteria:

          -  History of cardiac disease including congestive heart failure > New York Heart
             Association (NYHA) Class II

          -  Subjects with type 1 or type 2 diabetes mellitus

          -  Subjects with fasting glucose >125 mg/dL in 2 independent measurements or glycated
             hemoglobin (HbA1c) ≥ 7%

          -  Moderate and severe hepatic impairment, i.e. Child-Pugh B or C

          -  Active infections of CTCAE (Common Terminology Criteria for Adverse Events Version
             4.03) Grade >2 or infections of CTCAE Grade 2 not responding to therapy

          -  Symptomatic metastatic brain or meningeal tumors unless the patient is > 3 months from
             definitive therapy, has a negative imaging study within 4 weeks of study entry and is
             clinically stable with respect to the tumor at the time of study entry.

          -  Subjects undergoing renal dialysis

          -  Previous or concurrent cancer that is distinct in primary site or histology from the
             cancer being evaluated in this study except cervical carcinoma in situ, treated basal
             cell carcinoma, superficial bladder tumors (Ta, Tis & T1) or any cancer curatively
             treated > 3 years prior to study entry

          -  Autologous bone marrow transplant or stem cell rescue within 4 months of study entry

          -  Treatment with oral steroids (dose ≥ 10 mg/day of methylprednisolone or equivalent)

          -  Clinically relevant findings in the ECG such as a second- or third-degree AV block,
             prolongation of the QRS complex over 120 msec or of the QTcF-interval over 450 msec

          -  Acute toxic effects of previous anticancer chemotherapy or immunotherapy have to be
             normalized to CTCAE Grade equal or lower than 1 (excluding alopecia)