Phase I Study of QLC5508 in Advanced Solid Tumors: C-QTc, Pharmacokinetics (PK) Comparisons and Drug-drug Interaction

A clinical trial of QLC5508 for advanced solid tumors The goal of this clinical trial is to learn if QLC5508 can be given safely to adults with advanced solid tumors. It will also learn how two different formulations of QLC5508 compare in the body, and whether other drugs affect QLC5508. The main questions it aims to answer are: Does a single injection of QLC5508 change the heart's electrical activity (QTc interval)? How do the test formulation and the reference formulation of QLC5508 compare in the body (pharmacokinetics)? Do other drugs (itraconazole, darolutamide, or rifampicin) change how the body processes QLC5508? Investigators will compare the test formulation to the reference formulation, and will also give QLC5508 together with itraconazole, darolutamide, or rifampicin to look for drug-drug interactions. Participants will: Receive QLC5508 by injection into a vein; Join one of three groups: two groups will receive both formulations of QLC5508 at different times (crossover) and also take rifampicin or itraconazole; the third group will take darolutamide with QLC5508; Have heart monitoring (Holter) during the first dose; Undergo regular blood tests, safety checks, and immunogenicity testing (to see if the body develops antibodies against QLC5508).