A Phase I/II, Open-label Study to Investigate the Safety, Tolerability, PK, and Preliminary Efficacy of FB849

Inclusion Criteria:

* Subject should understand, sign, and date the written ICF prior to screening.
* Male or female aged 18 years or older.
* Subjects must have at least 1 measurable target lesion according to RECIST version 1.1.
* Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1
* Life expectancy ≥ 3 months in the opinion of the investigator.
* Adequate organ function and bone marrow function as indicated by the following screening assessments performed within 14 days prior to the first dose of study treatment

Exclusion Criteria:

* Known allergy or hypersensitivity to any component of the study treatment.
* Has a known additional malignancy that is progressing or has required active treatment.
* Has abnormal or inadequately controlled endocrine function.
* Inability to take oral medication or significant nausea and vomiting, malabsorption, external biliary shunt, or significant bowel resection that would preclude adequate absorption of oral medication.
* Previous anti-cancer therapy, including chemotherapy (chemotherapy with nitrosourea or mitomycin should be at least 6 weeks prior to initiation of study treatment), radiotherapy, molecular targeted therapy, or other investigational drugs received ≤ 4 weeks; endocrine therapy ≤ 2 weeks or ≤ 5-half-lives (whichever is shorter) prior to initiation of study treatment.