A Study of ADRX-0405 in Subjects With Select Advanced Solid Tumors

Inclusion Criteria: * Phase 1a Dose Escalation: Subjects with histologically confirmed select advanced solid tumors, including metastatic castration resistant prostate cancer (mCRPC), gastric cancer (GC), and non-small cell lung cancer (NSCLC). * Phase 1b Dose Expansion: Subjects with histologically confirmed prostate adenocarcinoma that is confirmed to be castration resistant (i.e., serum testosterone \< 50 ng/dL \[\< 2.0 nM\]) and that is intolerant/resistant to standard of care (SOC) therapies. * Measurable disease according to RECIST version 1.1 or evaluable disease per PCWG3 for subjects with prostate cancer * Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 in 1a; 0-2 in 1b * Adequate hematologic, liver, and renal function Exclusion Criteria: * Active and uncontrolled central nervous system metastases * Significant cardiovascular disease * History of another malignancy other than the one for which the subject is being treated on this study within 3 years * Receipt of any anticancer or investigational therapy within: 5 elimination half-lives or 14 days (whichever is less); 4 weeks for any therapeutic radiopharmaceutical for prostate cancer * History of (non-infectious) ILD/pneumonitis that required steroids within 2 years of study enrollment, has current ILD/pneumonitis, or where suspected ILD/pneumonitis cannot be ruled out by imaging at screening. * Receiving systemic antimicrobial treatment for active infection; routine antimicrobial prophylaxis is permitted