This study is an open-label, single arm, dose escalation and dose expansion phase 1 study to evaluate the safety, tolerability, pharmacokinetics and preliminary efficacy of BPI-21668 in solid tumor patients. In dose escalation phase, biomarker status is not required, but in dose expansion phase patients are required to harbor PIK3CA mutation.

Inclusion Criteria:

1. Age ≥18 and ≤70 years, male and female patients;
2. Life expectancy ≥ 12 weeks;
3. ECOG performance score 0-1;
4. Locally advanced or relapsed/metastatic solid tumor patients, who had disease progression after standard therapy, intolerable to standard therapy or for whom no standard therapy exists, PIK3CA mutation status is required for dose expansion phase;
5. Evaluable lesion required for dose escalation phase and measurable lesion as per RECIST 1.1 required for dose expansion phase;
6. Adequate organ function;
7. Signed informed consent.

Exclusion Criteria:

1. Prior use of PI3K、mTOR or AKT inhibitor;
2. Prior other malignant tumor;
3. Unstable, symptomatic primary CNS tumors/metastasis or leptomeningeal metastases ;
4. Type I or type II diabetes;
5. Inadequate wash-out of prior anti-cancer therapies;
6. Cardiac disorders;
7. Instable systemic diseases;
8. Acute or chronic pancreatitis;
9. Pregnancy or lactation;
10. Other protocol specified criteria.