RecruitingPhase 1Drug trialA Study to Evaluate the Safety,Tolerability, Pharmacokinetics and Clinical Activity of Mocertatug Rezetecan for Injection in Participants With Advanced Solid Tumors (BEHOLD-1)The goal of this study is to assess the safety and tolerability of Mocertatug Rezetecan . The study will also see how the levels of Mo-Rez change over time at different dose amount