This study investigates the safety and effectiveness of an investigational medication for treating advanced solid tumors that express mesothelin, a protein found on the surface of some cancer cells. The study will test the investigational medication alone or in combination with other treatments to see how well it works and how safe it is for patients.

Participants will undergo various study procedures to monitor their health and the effects of the treatment. The study will include a dose-finding phase to determine the safest dose when the investigational medication is combined with other drugs. This phase will help identify the maximum tolerated dose, which is the highest dose that does not cause unacceptable side effects.

• Who can participate: Adults with advanced or metastatic mesothelin-expressing tumors can participate. Participants must have at least one measurable lesion and adequate organ function. Those with more than one prior anti-tubulin agent or certain medical conditions may be excluded.
• Study details: Participants will receive either the investigational medication alone or in combination with other treatments. The study includes a dose-finding phase to ensure safety and determine the best dose levels.