GST101 in Participants With RAS-Mutant Advanced Solid Tumors

This is an open-label, multicenter Phase I/II trial to evaluate the safety, tolerability, pharmacokinetics, and preliminary efficacy of oral GST101 in adult participants with RAS-mutant advanced solid tumors. Phase I consists of dose escalation and dose-expansion parts. Dose escalation uses accelerated titration design combined with 3+3 design to determine maximum tolerated dose (MTD) and recommended Phase II dose (RP2D). Safety, dose-limiting-toxicity (DLT), PK and preliminary efficacy will be assessed. Phase II (indication-exploration) enrolls participants in four tumor-specific cohorts including RAS-mutant NSCLC, colorectal cancer, pancreatic ductal adenocarcinoma and other advanced solid tumors refractory to standard-of-care therapies. Participants receive GST101 orally once-daily in 21-day cycles until disease progression, unacceptable toxicity, withdrawal of consent, or loss of clinical benefit. Tumor assessments follow RECIST 1.1. Safety, PK, QTc and exploratory biomarker analyses will be performed.

Inclusion Criteria: * Aged ≥18 years, male or female, with signed informed consent. * Histologically or cytologically confirmed RAS-mutated advanced solid tumor, with disease progression or intolerance to standard anti-tumor therapy, or no available standard treatment. * For Phase II cohorts: eligible RAS-mutated advanced NSCLC, colorectal cancer, pancreatic cancer or other solid tumors meeting corresponding line-of-treatment criteria. * ECOG performance status 0 or 1. * Estimated life expectancy ≥ 3 months. * At least one measurable lesion per RECIST 1.1. * Adequate hematological, hepatic and renal organ function without supportive treatment within 14 days before dosing, meeting prespecified laboratory thresholds. * Fertile participants agree to effective contraception from consent to 4 months after last dose; female participants have negative pregnancy test and no lactation at baseline. Exclusion Criteria: * Symptomatic or uncontrolled central nervous system metastases, spinal cord compression or meningeal carcinomatosis. * Active or previous malignant tumor within 5 years (except permitted low-risk in-situ or superficial tumors). * Uncontrolled large-volume serous cavity effusion. * Active HIV, hepatitis B/C, syphilis or tuberculosis infection. * History of allogeneic organ or stem cell transplantation. * Severe uncontrolled cardiovascular, pulmonary, hepatic, renal, neurological or metabolic diseases within 6 months prior to enrollment. * QTcF \>480 ms, long QT syndrome, reduced left ventricular ejection fraction or uncontrolled severe arrhythmia/hypertension. * Severe cutaneous adverse drug reaction history or uncontrolled electrolyte/metabolic disorders. * High bleeding risk, active gastrointestinal bleeding or recent venous thromboembolism within 6 months. * Hypersensitivity to study drug or excipients. * Pregnancy, lactation, uncontrolled psychiatric disorder or substance abuse. * Prior treatment with any RAS-targeted inhibitor. * Receipt of prohibited anti-tumor drugs, strong CYP3A modulators within required washout periods before dosing. * Unresolved \>Grade 1 toxicity from prior anti-tumor therapy. * Impaired oral drug absorption or inability to take oral medication. * High-risk QTc factors and prohibited medications for QTc assessment subpopulation. * Major surgery within 4 weeks before enrollment or planned surgery during study period. * Any other condition considered inappropriate for study enrollment by the investigator.