This will be a phase 1, multicenter, open-label trial to evaluate the safety, tolerability, PK and efficacy of ZN-A-1041 as a monotherapy or in combination in patients with HER2-positive advanced solid tumors.

The study will consist of three phases: phase 1a (dose escalation with ZN-A-1041 monotherapy), phase 1b (dose escalation with ZN-A-1041 in combination with Capecitabine and Trastuzumab) and phase 1c (dose expansion with ZN-A-1041 in combination with Capecitabine and Trastuzumab).

Phase 1a of the study will adopt the "modified 3+3" dose escalation design with a total of 7 planned dose levels. Patients with HER2-positive advanced solid tumor (including those with brain metastases) will be enrolled to receive a single-dose administration of ZN-A-1041 followed by multiple-dose administration of ZN-A-1041.

Phase 1b of the study will adopt the "traditional 3+3" dose escalation design. In phase 1b, patients with HER2-positive advanced breast cancer (including those with brain metastases) will be enrolled to receive multiple doses of ZN-A-1041 in combination with Capecitabine and Trastuzumab.

In phase 1c patients with HER2-positive breast cancer with brain metastases were planned to be enrolled to receive ZN-A-1041 in combination with Capecitabine and Trastuzumab The dose levels will be determined based on the recommended doses obtained from the Phase 1b study, and the possible changes in the dosage form and the food effect study, which will be decided by the sponsor and the investigator after discussion.

Each phase of the study includes a screening period, a treatment period and a follow-up period. During the trial, the safety, tolerability, PK and efficacy data of ZN-A-1041 as monotherapy and in combination with Capecitabine and Trastuzumab in the subjects will be collected and analyzed, thereby providing RP2D for the subsequent clinical trials.

Key inclusion criteria:

11. ECOG performance status of 0 to 1 2. HER2-positive is defined as Immunohistochemistry (IHC) (++) and Fluorescence In Situ Hybridization (FISH) positive, or IHC (+++).

3. Phase 1a study will enroll patients with unresectable or metastatic HER2-positive advanced solid tumor; Phase 1b study will enroll patients with unresectable locally-advanced or metastatic HER2+ breast cancer.

i. For patients who have no brain metastases, the following criteria should be met:

1. Patients should be relapsed or refractory to existing therapy(ies) or have been intolerant of such therapies
2. Have at least one extracranial measurable lesion by RECIST v1. 1 ii. For patients with brain metastasis, the following criteria should be met:

1) Have received prior treatment or patient declined the above treatment; 2) Patients with HER2-positive gastric cancer must have previously received Trastuzumab 3) Do not require immediate local treatment during the trial period, and meet either of the following two criteria:

1. For patients who have received previous local treatment (surgery, whole brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS)) for brain metastases, stable or progression of intracranial lesions is required. Interval from prior local therapy could be 3 weeks from WBRT and 2 weeks from SRS.
2. Symptomatic or not, patient has not received previous local treatment (surgery or radiotherapy) for brain metastases as long as no local therapy is needed during the trial period.

iii. In Phase 1a, for patients who have received previous tyrosine kinase inhibitor (TKI) treatment, chemotherapy, antibody, or antibody-drug conjugate (ADC), the interval between the last treatment and the first administration of the study drug in this trial should be at least 2 weeks. In Phase 1b, for patients who have received previous trastuzumab or other antibodies, the interval between the last treatment and the first administration of the study drug in this trial should be at least 3 weeks.

4. Phase 1c study will enroll patients with unresectable locally-advanced or metastatic HER2+ breast cancer with brain metastases.

i. For patients with brain metastasis, patients do not require immediate local treatment during the trial period, and meet either of the following two criteria:

1. For patients who have received previous local treatment (surgery, whole brain radiotherapy (WBRT) and stereotactic radiosurgery (SRS)) for brain metastases, stable or progression of intracranial lesions is required. Interval from prior local therapy could be 3 weeks from WBRT, 2 weeks from SRS and 4 weeks from surgery
2. Symptomatic or not, patient has not received previous local treatment (surgery or radiotherapy) for brain metastases as long as no local therapy is needed during the trial period
3. Have at least one measurable lesion and is suitable for accurate repeated assessable by RECIST 1.1, and the patient has an imaging-diagnosable intracranial lesion;
4. Patients should not include suspected or confirmed meningeal metastases;
5. The patient had no disease progression with previous 12 weeks' capecitabine therapy;
6. No capecitabine therapy within 6 months;
7. Patient should not previously treat with a tyrosine kinase inhibitor (TKI). Previous treatment with trastuzumab or other antibodies should be at least 3 weeks apart from the first treatment

Key exclusion criteria:

1. Subjects who have participated in any clinical study or received any clinical study drug within 4 weeks prior to the first administration

2. There is evidence that other primary tumors are present at the same time;

3. Previous cumulative dose of doxorubicin exceeds 360mg/m2 or its equivalent dose of similar drugs;

4. CNS Exclusion - Based on screening brain MRI and clinical assessment

   1. Progressive neurologic impairment or increased intracranial pressure (including nausea, vomiting, blurred vision, headache, epilepsy, etc.)
   2. Any intracranial lesion thought to require immediate local therapy
   3. Require antiepileptic treatment (except for these patients with stable seizures require continuous Levetiracetam therapy).
   4. Ongoing use of systemic corticosteroids for control of symptoms of brain metastases at a total daily dose of > 2 mg of dexamethasone (or equivalent)