The goal of this clinical trial is to evaluate the safety and tolerability of escalating doses of ABT-301 in combination with fixed doses of tislelizumab 200 mg IV infusion and bevacizumab 7.5 mg/kg IV infusion Q3W, in participants with pMMR/non-MSI-H colorectal cancer (CRC). It will also determine the maximum tolerated dose (MTD) and select the recommended Phase 2 dose (RP2D) of ABT-301.
Participants will receive ABT-301 administered once daily (QD ±3 hours) or twice daily (Q12H ±3 hours, at least 9 hours apart) with water in 21-day treatment cycles. Tislelizumab 200 mg IV and bevacizumab 7.5 mg/kg IV Q3W will be given in both parts of the study.
Participant must be ≥18 years at the time of signing the informed consent.
Participant with pMMR/non-MSI-H advanced/recurrent histologically confirmed CRC with at least one measurable lesion, per RECIST version 1.1.
Participant must have received ≥2 lines of prior systemic therapy (including but not limited to chemotherapeutic agents of 5-fluorouracil, oxaliplatin, irinotecan; participant may or may not have received biologic agents such as cetuximab, panitumumab, aflibercept, ramucirumab, bevacizumab; tyrosine kinase inhibitors of regorafenib, fruquintinib).
Participant must submit an archival formalin-fixed, paraffin-embedded tumor specimen collected within 5 years before screening. If archival specimens are unavailable, alternative samples, such as colon endoscopy biopsy, are acceptable.
History of leptomeningeal disease.
Active or history of autoimmune disease or immune deficiency, including, but not limited to, myasthenia gravis, myositis, autoimmune hepatitis, systemic lupus erythematosus, rheumatoid arthritis, psoriatic arthritis, inflammatory bowel disease, antiphospholipid antibody syndrome, Wegener granulomatosis, Sjögren syndrome, Guillain-Barré syndrome, multiple sclerosis, or ankylosing spondylitis.
Participants with the following conditions are eligible for the study: autoimmune-related hypothyroidism on thyroid-replacement hormone are eligible for the study. Participants with controlled Type 1 diabetes mellitus who are on an insulin regimen are eligible for the study.
Participants with eczema, psoriasis, lichen simplex chronicus, or vitiligo with dermatologic manifestations only (e.g., participants with psoriatic arthritis are excluded) are eligible for the study provided all of following conditions are met: 1. Rash must cover <10% of body surface area 2. Disease is well controlled at baseline and requires only low-potency topical corticosteroids 3. No occurrence of acute exacerbations of the underlying condition requiring psoralen plus ultraviolet A radiation, methotrexate, retinoids, biologic agents, oral calcineurin inhibitors, or high-potency or oral corticosteroids within the previous 12 months.
Sequential
ABT-301
DrugABT-301 is an oral histone deacetylase inhibitor (HDACi) administered in capsule form once daily (QD ±3 hours) or every 12 hours (Q12H ±3 hours, with at least 9 hours between doses) with water in 21-day treatment cycles. In Part 1 (dose-escalation phase), participants receive escalating doses of ABT-301 (50 mg QD, 100 mg QD, 50 mg Q12H, 150 mg QD, or 75 mg Q12H). Tislelizumab 200 mg and bevacizumab 7.5 mg/kg will be administered through IV infusion on Day 1 of every 21-day treatment cycle. This phase aims to determine the maximum tolerated dose (MTD) and/or recommended Phase 2 dose (RP2D) of ABT-301 when combined with tislelizumab and bevacizumab. In Part 2 (dose-optimization phase), two ABT-301 doses/schedules will be selected for further evaluation of antitumor activity, safety, and tolerability in adults with pMMR/non-MSI-H colorectal cancer (CRC).
Tislelizumab
DrugTislelizumab is a humanized immunoglobulin G4-variant monoclonal antibody (mAb) blocking programmed cell death protein 1 (PD-1). Tislelizumab 200 mg will be administered through IV infusion on Day 1 of every 21-day treatment cycle in combination with ABT-301 and bevacizumab throughout both parts of the study.
Bevacizumab (Avastin)
DrugBevacizumab (Avastin®) is a recombinant humanized monoclonal IgG1 antibody which binds to and neutralizes VEGF. Neutralization of VEGF by bevacizumab has been shown to inhibit the VEGF-induced proliferation of human endothelial cells in vitro and to decrease micro-vessel density and interstitial pressure in tumor xenografts in vivo. Bevacizumab 7.5 mg/kg will be administered through IV infusion on Day 1 of every 21-day treatment cycle in combination with ABT-301 and tislelizumab, throughout both parts of the study.
Part I - To evaluate the safety and tolerability of escalating doses of ABT-301 in combination with fixed doses of tislelizumab 200 mg IV infusion and bevacizumab 7.5 mg/kg IV infusion Q3W, in participants with pMMR/non-MSI-H CRC.
Endpoints include: Adverse Event will be graded using the NCI CTCAE V5.0.
Part I - To determine the Maximum tolerated dose (MTD) and select the recommended Phase 2 dose (RP2D) of ABT-301.
Endpoints include: Incidence of DLTs during the first cycle of treatment.
Part II - To evaluate the efficacy of two dosages/schemes of ABT-301 in combination with tislelizumab and bevacizumab.
Endpoint: ORR per Investigator assessment, according to RECIST version 1.1.
Part I - Objective Response Rate (ORR) per Investigator Assessment According to RECIST v1.1
Part I - Duration of Response (DOR) per Investigator Assessment According to RECIST v1.1
Part I - Progression-Free Survival (PFS) per Investigator Assessment According to RECIST v1.1
Part I - Overall Survival (OS)
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Anbogen Therapeutics, Inc.
Lead sponsor
Fortrea
Collaborator
