A Phase IIa of Infigratinib in Subjects With Locally Advanced or Metastatic Gastric Cancer or Gastroesophageal Junction Adenocarcinoma With FGFR2 Amplification or Other Advanced Solid Tumors With Other FGFR Alterations

The subject will go through 4 periods, including Pre-screen period, screening period, treatment period and follow up period.

Pre-screening period (up to 28 days) For cohort 1, subject sign pre-screening ICF( Inform consent ), subject will do tumor biopsy or provide FFPE samples before prescreening for FGFR2-amp detection by FISH from the central laboratory. If the result is positive, subjects can go through the main screening stage, otherwise participants will be considered a prescreen failure. subjects can go through the main screening stage, otherwise participants will be considered a prescreen failure.

Screening period ( All cohorts; up to 28 days): Subjects who had positive genetic result could sign main ICF for all the screening examinations and establish study baseline documents. Only the eligible participants could enter the next treatment period.

Treatment period: Eligible subjects will be orally administered Infigratinib (125mg, QD) for 3 weeks on, 1-week off in each 28-day cycle until the occurrence of unacceptable toxicity, disease progression, withdrawing informed consent, death, contact lost, starting a new anticancer therapy, etc (whichever occurs first). During this period, subjects will be routinely assessed efficacy status by radiographic check at W9/W17/W25/W33 . After that, subjects will be evaluated every 12 weeks until disease progression. The safety assessment will be performed at cycle 1- 4;

Follow up period: Once a treatment discontinuation happens, subjects should return to the hospital within 30 days to receive a complete safety examination. Subjects with treatment discontinuation or disease progression should directly enter the follow-up period, visit approximately every 3 months for survival status reporting until withdrawing informed consent, death, contact lost, starting a new anti-cancer therapy, etc. (whichever occurs first).