Study of ECI830 Single Agent or in Combination in Patients With Advanced HR+/HER2- Breast Cancer and in Patients With Other Advanced Solid Tumors

Prior treatment

• Previous treatment with a CDK2 inhibitor at any time.
• Presence of symptomatic CNS metastases or CNS metastases that require local therapy or increasing doses of corticosteroids within 2 weeks prior to study entry.
• Patients who could not tolerate the prescribed dose of ribociclib during a previous course of treatment, requiring dose reduction or permanent discontinuation due to adverse events.
• For patients with BC: Patient is concurrently using hormone replacement therapy.

Other illness

• Patients with symptomatic visceral disease or any disease burden that makes the patient ineligible for endocrine-based therapy.

Lab values

• Patients with inadequate bone marrow and/or organ functions with out-of-range laboratory values.
• Clinically significant, uncontrolled heart disease and/or cardiac repolarization abnormality including MI, CABG, long QT syndrome, or risk factors for TdP.

Other

• For the combination treatment:
• WOCBP who are unwilling to use highly effective contraception methods, pregnant or nursing women.
• Other protocol-defined inclusion/exclusion criteria may apply.

• Age ≥ 18 years old.
• Patients with one of the following indications:
• Phase I:
• HR+/HER2- aBC with disease progression on or following at least one line of hormone-based therapy in combination with a CDK4/6i and at least one additional line of systemic therapy for metastatic disease.
• Histologically and/or cytologically confirmed diagnosis of locally advanced or metastatic cancer with a CCNE1 amplification. For dose expansion only: no more than 3 prior lines of therapy for advanced or metastatic disease.
• Patients with ES-SCLC and disease progression on or after standard of care (SoC). For dose expansion only: no more than 2 prior lines of therapy for advanced or metastatic disease are allowed.
• Phase II:
• HR+/HER2- aBC with disease progression on an aromatase inhibitor or tamoxifen in combination with a CDK4/6 inhibitor for unresectable/metastatic disease with no more than 2 lines of endocrine therapy.
• Measurable disease as determined by RECIST v1.1.
• BC only: If no measurable disease is present, then at least one predominantly lytic bone lesion must be present that can be accurately assessed at baseline and is suitable for repeated assessment.