This study is evaluating a new oral medicine (called ZN-A-1041) when given by itself or in combination with other treatments in people with HER2+ advanced solid cancersA Phase 1 Clinical Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Efficacy of ZN-A-1041 Enteric Capsules as a Single Agent or in Combination in Patients With HER2-Positive Advanced Solid Tumors

Inclusion

1. 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.

   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. Patients with HER2-positive breast cancer should have previously received Trastuzumab, Pertuzumab, Trastuzumab emtansine(T-DM1) and a taxane.
   3. Patients with HER2-positive gastric cancer must have previously received trastuzumab.
   4. Have measurable or non-measurable disease assessable by RECIST 1.1.

   For patients with brain metastasis, the following criteria should be met:

   1. Patients with HER2-positive breast cancer must have received prior treatment with Trastuzumab, Pertuzumab and T-DM1, and a taxane 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: i) 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; ii) 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.

   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.

4. Phase 1b and Phase 1c study will enroll patients with unresectable locally advanced or metastatic HER2+ breast cancer.

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

   1. For arm 1 and arm 2, patients should be relapsed or refractory to existing therapy(ies), with a history of prior treatment with trastuzumab and a taxane. For arm3, patients have received 4-8 cycles (21-day cycles) of previous treatment with trastuzumab, pertuzumab, and taxane as first-line therapy for advanced HER2+ breast cancer with no evidence of disease progression.
   2. Have measurable or non-measurable disease assessable by RECIST 1.1

   For patients with brain metastasis, the following criteria should be met:

   1. For arm 1 and arm 2, patients should be relapsed or refractory to existing therapy(ies), with a history of prior treatment with trastuzumab and a taxane. For arm3, patients have received 4-8 cycles (21-day cycles) of previous treatment with trastuzumab, pertuzumab, and taxane as first-line therapy for advanced HER2+ breast cancer with no evidence of disease progression.
   2. Do not require immediate local treatment during the trial period, and meet either of the following two criteria: i) 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; ii) 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.
5. Suspected or confirmed leptomeningeal metastasis are allowed in Phase 1b, but not allowed in Phase 1c.
6. In Phase 1b arm1 and arm2, 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. For arm3, patients should not have prior treatment for unresectable locally-advanced or metastatic HER2+ breast cancer with and without brain metastasis, except for ongoing Herceptin, Perjeta or PHESGO and taxane.
7. In Phase 1c arm1 and arm2, Patients should not have received prior treatment with tucatinib, afatinib, or any other investigational anti-HER2, anti-EGFR, or HER2 TKI agent. Prior treatment with lapatinib or neratinib within 12 months of starting study treatment (except in cases where they were given for ≤ 21 days and was discontinued for reasons other than disease progression or severe toxicity). Prior treatment with pyrotinib for recurrent of mBC (except in cases where pyrotinib was given for ≤ 21 days and was discontinued for reasons other than disease progression or severe toxicity). For arm3, patients should not have prior treatment for unresectable locally-advanced or metastatic HER2+ breast cancer with and without brain metastasis, except for ongoing Herceptin, Perjeta or PHESGO and taxane.