A Phase I/II Study of VLS-1488 in Subjects With Advanced Cancer

Key Inclusion Criteria: * All Parts: Age ≥ 18 years, ECOG Performance Status ≤ 1, at least 1 site of measurable disease evaluable by CT scan or MRI per RECIST 1.1, able to take oral medication without alteration * Dose Escalation: No available therapeutic options to provide clinically meaningful benefits in the following tumor types: High Grade Serous Ovarian Cancer, Squamous Non -Small Cell Lung Cancer, Triple Negative Breast Cancer, Gastric Adenocarcinoma (not EBV+), Colorectal, Esophageal Squamous Cell Carcinoma, Esophageal Adenocarcinoma, Gastroesophageal Junction, Bladder (transitional cell), Head and Neck Squamous Cell Carcinomas (not nasopharynx, sinonasal or lip), Ovarian Carcinosarcoma, CN-high Endometrial/Uterine * Dose Expansion: Must have been previously treated with several lines of standard of care treatment specified in the protocol in the following tumor types: High Grade Serous Ovarian Cancer, Squamous Non-Small Cell Lung Cancer, Triple Negative Breast Cancer, Gastric Adenocarcinoma (not EBV+), Colorectal, Esophageal Squamous Cell Carcinoma, Esophageal Adenocarcinoma, Head and Neck Squamous Cell Carcinomas (not nasopharynx, sinonasal or lip), CN-high Endometrial/Uterine Key Exclusion Criteria: * MSI-H, dMMR, POLE gene hotspot mutated, or known hypermutator phenotype * Previously received KIF18A inhibitor * Current CNS metastases or leptomeningeal disease * Cardiac parameters: MI or stroke ≤ 1 year, unstable angina/PE/DVT/CABG ≤ 6 months, NYHA Class ≥ II, LVEF \< 50% * Inability to comply with concomitant medication restrictions with respect to strong inhibitors and inducers of CYP3A, and clinical inhibitors of MDR1 (P-gp) and BCRP * Any clinically significant ascites or pleural effusions at time of enrollment, or any therapeutic paracentesis or thoracentesis within 28 days of planned first dose of study drug * Bowel obstruction or GI perforation within 6 months of planned first dose of study drug