Phase I Study of FXS0683 in the Treatment of Blood Tumors

This is a first-in-human, multicenter, open-label, single-arm Phase I study of FXS0683 tablets in participants with relapsed or refractory hematologic malignancies, designed to evaluate safety, tolerability, PK, and preliminary antitumor activity.The study consists of a dose-escalation phase and a dose-expansion phase. The primary objective of dose escalation is to assess safety and tolerability and to determine the MTD and/or RP2D. Dose escalation will follow an accelerated titration design combined with a Bayesian Optimal Interval (BOIN) design. The initial cohort will enroll one participant; if a treatment-related adverse event of Grade ≥2 occurs during the dose-limiting toxicity (DLT) observation period, the cohort will transition to a BOIN design and expand to include additional participants. Dose escalation may proceed in the absence of DLTs among evaluable participants. The dose-expansion phase is intended to further evaluate safety and preliminary efficacy at selected dose level(s). Expansion may be initiated based on emerging safety, tolerability, and PK data from the dose-escalation phase without requiring completion of all escalation cohorts.