New Hope for a Cruel Disease: Nebokitug's Promise for PSC Patients

TEL AVIV, Israel – December 02, 2025 – For the thousands of people diagnosed with Primary Sclerosing Cholangitis (PSC), the news is often devastating. It’s a rare, chronic disease where the body’s own immune system attacks the bile ducts, leading to relentless inflammation, scarring, and eventual liver failure. With no effective medical treatments and no cure, the only definitive option is a liver transplant. Now, a recent development is casting a ray of hope into this challenging landscape, offering a tangible sign of progress for a community in desperate need.

Chemomab Therapeutics, a clinical-stage biotechnology company, has announced that the full results of its Phase 2 clinical trial for an investigational drug, nebokitug, have been published in the prestigious American Journal of Gastroenterology. The peer-reviewed data validates promising earlier reports, showing that the drug is not only safe but also demonstrates the potential to modify the course of this unforgiving disease, providing a critical step forward on the long road toward an approved therapy.

Tackling a Two-Headed Dragon: Inflammation and Fibrosis

To understand the significance of this milestone, one must first grasp the nature of PSC. The disease wages a two-front war on the liver. First, persistent inflammation damages the bile ducts, the crucial plumbing system that carries digestive fluid from the liver. Second, this damage triggers fibrosis—the formation of scar tissue—which progressively hardens and obstructs the ducts. This destructive cycle ultimately leads to cirrhosis, liver failure, and a significantly increased risk of bile duct cancer.

For decades, the complexity of this process has thwarted drug development, with many promising candidates failing in late-stage trials. Most treatments have focused on managing symptoms like severe itching and fatigue, or treating infections, rather than halting the underlying disease.

Nebokitug represents a different approach. It is a first-in-class antibody designed to neutralize a specific protein called CCL24. Research has shown that CCL24 is a key player in orchestrating both the inflammatory and fibrotic processes that drive PSC. By targeting this single protein, nebokitug aims to deliver a dual blow to the disease, calming the immune-driven inflammation while also disrupting the signals that lead to progressive scarring. This innovative mechanism is what distinguishes it in a field hungry for a breakthrough.

Promising Signals of a Disease-Modifying Effect

The Phase 2 SPRING trial, which enrolled 76 patients across the U.S., Europe, and Israel, was designed to test the safety and biological activity of nebokitug. The newly published results confirm the drug was safe and well-tolerated over a treatment period of up to 48 weeks.

More importantly, the study showed clear signs that the drug was hitting its mark. Patients treated with nebokitug, particularly at a higher dose, showed numerical improvements across a range of key biomarkers that are closely linked to PSC outcomes. These included:

• Enhanced Liver Fibrosis (ELF) Score: A blood test that measures active liver scarring. Patients on placebo saw this score worsen, while those on nebokitug showed a reduction, an effect that was sustained over 48 weeks.
• PRO-C3: Another key marker of active fibrosis, which also showed sustained reductions in the treatment groups.
• Liver Stiffness Measurement (LSM): A non-invasive ultrasound technique that measures the stiffness of the liver, which correlates with the degree of fibrosis. Patients with moderate-to-advanced disease showed a statistically significant reduction in liver stiffness compared to placebo.

Christopher Bowlus, MD, a leading investigator on the trial and Chief of Gastroenterology and Hepatology at the UC Davis School of Medicine, commented on the findings in the company's announcement. “In the SPRING trial, nebokitug demonstrated that it has the potential to change the lives of patients with PSC by reducing fibrosis and inflammation, which should lead to improved outcomes,” he stated. “The promising clinical data... are good news for patients with PSC, who are in desperate need of an effective therapy.”

Perhaps most compelling was the consistency of the results. In the subgroup of patients with moderate-to-advanced fibrosis—representing about half of all PSC patients—half of those receiving the 20 mg/kg dose of nebokitug saw improvements in all three key biomarkers. In the placebo group, not a single patient achieved this result. This consistency provides strong evidence that nebokitug’s biological activity could translate into meaningful clinical benefits.

A Clearer Path Forward

Positive trial data is one thing; navigating the complex regulatory pathway to get a drug to patients is another. Here, too, Chemomab has made significant progress. The company has already received Orphan Drug designation from both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA), a status granted to encourage the development of treatments for rare diseases. It also has FDA Fast Track designation, which is designed to expedite the review of drugs that fill a serious unmet medical need.

Building on this momentum, Chemomab has reported alignment with both regulatory bodies on a streamlined path forward: a single, pivotal Phase 3 registration trial. This trial will be designed to measure a primary endpoint based on clinical events, such as the need for liver transplantation or other major liver-related complications. Proving a drug can delay or prevent these events is the gold standard for approval and would represent an unequivocal victory for patients.

While the journey is far from over—Phase 3 trials are long, expensive, and carry no guarantee of success—this clear regulatory roadmap is a major de-risking event. For a small biotech company like Chemomab, taking on a challenge that has stumped larger pharmaceutical giants is a monumental task. The company is actively seeking strategic partnerships to fund and execute the upcoming trial, a common strategy to bring high-potential assets across the finish line.

For the PSC community, which has watched other potential therapies fall short in recent years, the publication of these results is more than just a scientific update. It is a validation of persistent research and a tangible reason for optimism. While caution remains essential, the data suggests that nebokitug is a highly credible candidate, bringing the prospect of the first-ever disease-modifying treatment for PSC one significant step closer to reality.