Phase 1 trial of CA-170, a novel oral small molecule dual inhibitor of immune checkpoints PD-1 and VISTA, in patients (pts) with advanced solid tumor or lymphomas.
TPS3099 Background: Programmed-death 1 (PD-1) and V-domain Ig suppressor of T-cell activation (VISTA) are independent immune checkpoints that negatively regulate T-cell function and are implicated in various malignancies. Preclinical studies have demonstrated that dual blockade of these pathways is synergistic. CA-170 is a first-in-class oral small molecule that directly targets both PD-1/PD-L1 and VISTA pathways and has shown anti-tumor activity in multiple preclinical models. Methods: The dose escalation phase has a target enrollment of 50 pts with advanced solid tumors or lymphomas onto escalating doses; the first four single-pt cohorts are accelerated titration but then switch to 3+3 design. The dose expansion phase has a target enrollment of 250 pts with select tumor types known to be responsive to anti-PD-1/L1 inhibitors and/or known to express PD-L1 or VISTA. Key eligibility criteria include: age ≥ 18 years, ECOG ≤1, adequate organ function, and ineligible for/did not respond to standard therapy including anti-PD-1/L1 inhibitors, where available. Primary objectives of this first-in-human study: safety, maximum tolerated dose, and recommended phase 2 dose. Secondary objectives: pharmacokinetics (PK) and anti-tumor activity. Exploratory endpoints: biomarkers and pharmacodynamic (PD) effects, which include changes in immune cell and peripheral cytokine populations in tumor (IHC/mRNA) and blood (flow cytometry/mRNA). Oral CA-170 is administered once daily in 21-day cycles. Response will be evaluated every other cycle per RECIST (v1.1) and Immune-related Response Criteria or by Cheson criteria (2007). Patients who discontinue treatment for reasons other than progressive disease will be followed for progression-free survival. Serial plasma, blood, and tumor samples will be collected for PK and PD evaluation. Clinical trial identifier: Clinical trial information: NCT02812875.