Study halted prematurely and will not resume; participants are no longer being examined or receiving intervention

The purpose of this study is to determine the safety profile and maximum tolerable dose (MTD) of GBR 1302 monotherapy in subjects with HER2 positive cancers

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.