Main Inclusion Criteria:

1. Patient with histologically-confirmed, locally advanced or metastatic tumor who has
progressed on standard therapy or for whom no standard therapy exists, with the
following restriction:

- Part I: solid tumors of any origin;

- Part II: breast and gastric tumors;

2. For Part II: HER2 tumor status as defined in the protocol;

3. ECOG performance status 1;

4. Life expectancy > 12 weeks;

5. Adequate organ function;

6. For Part II: measurable disease.

Main Exclusion Criteria:

1. Anthracycline treatment within 3 months and/or abnormal cardiac biomarker values;

2. Other anticancer therapy (except for LHRH agonists) within 4 weeks (6 weeks for
trastuzumab, (ado-)trastuzumab emtansine, nitrosoureas and mitomycin C);

3. History of infusion-related reactions and/or hypersensitivity to trastuzumab or
(ado-) trastuzumab emtansine;

4. Severe, uncontrolled systemic disease;

5. LVEF < 55%, or a history of absolute decrease in LVEF of 10% points to < 50% during
previous treatment with trastuzumab or (ado-)trastuzumab emtansine, or a history of
decrease in LVEF to < 40% during previous treatment with trastuzumab or
(ado-)trastuzumab emtansine;

6. History of clinically significant CV disease;

7. Symptomatic brain metastasis, or therapy for brain metastasis (excluding PCI and
dexamethasone treatment with stable or decreasing daily dose) within 4 weeks.

Minimum Eligible Age: 18 Years

Maximum Eligible Age: N/A

Eligible Gender: Both