New York, United States, September 20, 2026
Accro Bioscience has announced that the first patient has been dosed in its Phase IIb clinical study of AC-101 for adults with moderate-to-severe ulcerative colitis (UC). The milestone marks the advancement of AC-101 into a later-stage clinical development program evaluating the investigational oral therapy in patients with active disease. The multicenter study is designed to assess the efficacy, safety and tolerability of AC-101, with clinical remission serving as the primary efficacy measure. The program represents an important step in Accro’s development of targeted therapies for inflammatory bowel disease (IBD) and builds on clinical evidence generated during earlier-stage development.
Accro Bioscience Advances AC-101 Into Phase IIb
The Phase IIb study is a randomized, double-blind, placebo-controlled, multicenter clinical trial designed to evaluate AC-101 in adults with moderate-to-severe ulcerative colitis. Participants will be randomized to receive different dose levels of AC-101 or placebo, allowing researchers to evaluate the candidate’s therapeutic activity and safety under controlled clinical conditions. The study will assess patients over the treatment period and continue monitoring clinical outcomes to characterize the potential benefits and risks associated with AC-101.The first-patient-dosed milestone indicates that the study has moved from preparation into active clinical evaluation.
According to Accro Bioscience, the trial is being conducted across multiple clinical sites and is intended to enroll patients with moderate-to-severe ulcerative colitis whose disease requires additional therapeutic options. The study will generate data that can help determine whether AC-101 should advance toward later-stage development. The company’s clinical development strategy is focused on therapies that target biological pathways involved in intestinal inflammation. By evaluating AC-101 in patients with active ulcerative colitis, the Phase IIb program is intended to provide a more comprehensive assessment of the candidate’s clinical profile and its potential role in treating IBD.
AC-101 Targets the RIPK2 Inflammatory Pathway
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AC-101 is an oral, selective receptor-interacting serine/threonine-protein kinase 2 (RIPK2) inhibitor being developed by Accro Bioscience. RIPK2 is an important signaling protein involved in the innate immune response and downstream inflammatory pathways associated with activation of NOD1 and NOD2 receptors. Abnormal or excessive activation of these pathways has been associated with inflammatory diseases, including ulcerative colitis and other forms of inflammatory bowel disease. By selectively targeting RIPK2, Accro aims to modulate inflammatory signaling while potentially providing an oral treatment approach. The company has described AC-101 as a selective small-molecule inhibitor designed to address inflammation associated with gastrointestinal disease. The Phase IIb study will be important for determining whether the mechanism observed in preclinical and earlier clinical research can translate into measurable improvements for patients with moderate-to-severe ulcerative colitis. The study’s controlled design is intended to provide clearer information on clinical efficacy, safety and dose response.
Phase IIb Trial Evaluates Clinical Remission
The primary endpoint of the Phase IIb study is clinical remission at Week 12, providing a measure of whether treatment can reduce disease activity to predefined levels. Additional endpoints are expected to evaluate other indicators of disease control, including endoscopic response, endoscopic remission, histologic outcomes and safety. Ulcerative colitis is a chronic inflammatory disease affecting the lining of the colon and rectum. Patients with moderate-to-severe disease can experience persistent diarrhea, rectal bleeding, abdominal pain and other symptoms that can significantly affect daily life. Although multiple therapies are available, some patients do not achieve adequate disease control or eventually lose response to treatment, creating continued demand for new therapeutic approaches.
Accro Bioscience said the Phase IIb program builds on earlier clinical development of AC-101 and is designed to provide additional evidence regarding its potential as a treatment for ulcerative colitis. The first-patient-dosed milestone therefore represents an important transition into a study capable of generating more extensive clinical efficacy and safety data. As the Phase IIb trial progresses, results will help determine whether AC-101 can demonstrate meaningful clinical activity in patients with moderate-to-severe ulcerative colitis. The data may also inform subsequent development decisions and regulatory planning for the investigational therapy. At this stage, AC-101 remains an investigational drug, and its safety and efficacy for ulcerative colitis have not yet been established. For Accro Bioscience, the initiation of the Phase IIb program strengthens the company’s position in inflammatory bowel disease drug development and advances its effort to develop novel oral therapies targeting inflammatory signaling pathways. The upcoming clinical data will be important in evaluating the potential of AC-101 and RIPK2 inhibition as a therapeutic strategy for patients living with moderate-to-severe ulcerative colitis.
Source: Accro Bioscience press release
