This is a phase 1b, open-label, dose-escalation study to evaluate the safety, tolerability, pharmacokinetics of Sapu003 in combination with Exemestane in in patients with advanced mTOR-sensitive solid tumors (HR+/HER2-negative breast cancer, renal cell carcinoma \[RCC\], neuroendocrine tumors \[NETs\], tuberous sclerosis complex \[TSC\]-associated tumors, and hepatocellular carcinoma \[HCC\]).
Sex and Age: Patients must be ≥ 18 years of age at the time of informed consent.
Cohort A (HR+/HER2- breast cancer): Eligible patients must be postmenopausal women, defined as women ≥ 18 years of age with amenorrhea for ≥ 12 consecutive months without another pathophysiological cause.
Cohort B (RCC, NETs, TSC-associated tumors, HCC): Eligible patients include both male and female adults with advanced disease.
Has histologically or cytologically documented advanced (metastatic or unresectable) hormone receptor-positive, HER2 negative breast cancer (advanced HR+ BC)
Patients with a history of other malignancies, except for adequately treated non-melanoma skin cancer, curatively treated in-situ carcinoma of the cervix, curatively treated in-situ carcinoma of the breast, or other solid tumors curatively treated with no evidence of disease for > 5 years.
Patients who have not completely recovered from any toxicities from previous chemotherapy, hormone therapy, immunotherapy, target therapy, or radiotherapies ≥ Grade 1 per NCI CTCAE version 5.0, with the exception of alopecia.
Prior chemotherapy within 30 days prior to screening (42 days for mitomycin C or nitrosoureas).
Prior immunotherapy, prior anti-tumor hormonal therapy (for breast cancer patients), and prior radiotherapy within 30 days prior to screening.