The primary objective is to evaluate the safety and tolerability of RC278; determine the maximum tolerated dose (MTD) and/or maximum administered dose (MAD) of RC278; and determine the recommended phase 2 dose (RP2D)， and assess the efficacy of RC278 at the RP2D dose;
Voluntarily participate in this study, sign the informed consent form, and be able to adhere to the study protocol;
Age between 18 and 75 years (including 18 and 75 years);
ECOG PS score of 0 or 1;
Expected survival ≥12 weeks;
Pregnant, breastfeeding, or intending to become pregnant subjects.
Subjects with brain metastases.
Subjects with unresolved toxicities from prior anti-tumor therapy not recovered to NCI-CTCAE v5.0 Grade 1.
Subjects with known hypersensitivity or delayed allergic reactions to any component of the investigational drug or similar drugs.