A phase I/II, first-in-human study of VLS-1488, an oral KIF18A inhibitor, in patients with advanced cancer.

TPS3181 Background: Chromosomal instability (CIN) is a hallmark of cancer characterized by high rates of chromosomal segregation errors during mitosis. This creates structural and numerical changes to chromosomes, driving genetic heterogeneity and cancer evolution. KIF18A is a mitotic kinesin protein shown to be important for successful division of cancer cells with CIN but not required for mitosis in normal diploid cells. Pre-clinical studies demonstrated that treatment of chromosomally unstable cancer cells in vitro and in xenograft models (HCC15 and OVCAR-3) with a KIF18A inhibitor resulted in failure of chromosomal congression, mitotic arrest, cell death and dose-dependent inhibition of tumor growth. VLS-1488 is an oral small molecule inhibitor of KIF18A that is being examined in an open-label, phase I/II, first-in-human study evaluating the safety, tolerability, pharmacokinetics (PK) and preliminary anti-tumor activity in advanced solid tumors with high prevalence of CIN. Methods: Key eligibility criteria include specific histologically confirmed metastatic or advanced tumor types with at least one site of measurable disease per RECIST 1.1, adequate organ function, and mismatch repair proficient/microsatellite stable.Eligible tumor types include high grade serous ovarian/fallopian tube/primary peritoneal cancer, squamous non-small cell lung cancer, triple negative breast cancer, gastric adenocarcinoma, gastroesophageal cancer, esophageal cancer, colorectal adenocarcinoma, transitional cell carcinoma of bladder, head and neck squamous cell carcinoma, ovarian or uterine carcinosarcoma, and uterine serous carcinoma. Subjects will receive VLS-1488 monotherapy continuously for 28-day cycles once daily. The study consists of two parts, Dose Escalation and Dose Expansion. Utilizing a Bayesian Optimal Interval (BOIN) design, Dose Escalation will examine the safety and tolerability of VLS-1488 at various dose levels (DLs) to identify the Maximum Tolerated Dose (MTD) and to select DLs for Dose Expansion. Dose Expansion may commence after the MTD or DLs of interest are identified. Dose Expansion will examine the safety, tolerability, preliminary efficacy and preliminary drug-drug interaction (DDI) and food effect risk of VLS-1488 in selected tumor types. Subjects enrolled to specific tumor type cohorts may be randomized to DLs of interest. Enrollment to Dose Escalation began in September 2023 and is ongoing. Clinical trial information: NCT05902988 .