Inclusion Criteria:

          1. Progressive HER2 positive solid tumours (immunohistochemistry [IHC] positive or
             equivocal) with no available standard or curative treatment.

          2. Eastern Cooperative Oncology Group (ECOG) performance score of 0-2.

        Exclusion Criteria:

          1. Active infectious disease considered by the Investigator to be incompatible with the
             protocol.

          2. Patients not recovered from any therapy-related toxicities from previous therapies to
             at least CTCAE ≤ Grade 1 except in case of liver metastases or Gilbert's Syndrome or
             alopecia.

          3. Brain metastases that are symptomatic or untreated or that require current therapy.

          4. Previous treatment with immunotherapy within 8 weeks of starting study medication,
             chemotherapy, radiotherapy, molecular-targeted therapy, or biological therapies
             (including HER2 directed therapies) within 4 weeks of starting study medication, or
             hormone therapy within 2 weeks of starting study medication.

          5. Use of any investigational drug within the past 4 weeks before start of study
             medication or concomitantly with this study except for investigational
             immune-stimulatory therapy (e.g. checkpoint-regulator targeted treatment). The minimum
             washout period should be 8 weeks before starting the study medication.