New Drug Shows Promise for Rare Liver Disease With No Current Cure

A new experimental drug called nebokitug has shown promising results in treating primary sclerosing cholangitis (PSC), a rare liver disease that currently has no effective treatments beyond liver transplantation. The multicenter trial, led by UC Davis Health, found the monoclonal antibody was safe and showed potential in reducing liver inflammation and scarring in 76 patients across five countries.

What Is Primary Sclerosing Cholangitis?

Primary sclerosing cholangitis is a chronic liver disease that causes inflammation and scarring of the bile ducts—the tubes that carry bile from your liver to your small intestine to help digest fats. When these ducts become damaged and narrow, bile builds up in the liver, leading to progressive liver injury over time.

The exact cause of PSC remains unclear, but most patients also have inflammatory bowel disease, suggesting a connection between intestinal inflammation and liver damage. While some people experience no symptoms initially, others may develop fatigue, itching, and jaundice as the disease progresses.

How Does the New Treatment Work?

Nebokitug works by blocking a protein called CCL24, which plays a key role in inflammation and scarring processes. In PSC patients, CCL24 levels are higher than normal and concentrate around the bile ducts, where they contribute to ongoing liver damage. By targeting this specific protein, the treatment aims to slow disease progression by reducing both inflammation and fibrosis.

The Phase 2 SPRING trial randomly assigned PSC patients to receive nebokitug at two different doses or a placebo through an IV every three weeks for 15 weeks. The study's main goals included:

• Safety Assessment: Monitoring patients for adverse reactions and side effects during treatment
• Liver Function Evaluation: Measuring liver health through blood tests, imaging, and markers linked to liver scarring
• Long-term Monitoring: Allowing patients who completed the initial phase to continue treatment for up to 48 weeks

"In the 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," said Christopher Bowlus, chief of Gastroenterology and Hepatology at UC Davis Health and one of the lead authors of the publication.

What Were the Key Results?

The results showed nebokitug was safe and well-tolerated across all participants. Most encouragingly, patients with more advanced liver scarring experienced improvements in key measures like liver stiffness and fibrosis markers compared to those receiving the placebo. These improvements suggest the treatment may help slow PSC progression by targeting the underlying inflammatory processes.

The positive results have paved the way for a pivotal phase 3 study to further evaluate the drug's effectiveness, which could eventually lead to U.S. Food and Drug Administration approval. "These results are good news for patients with PSC, who are in desperate need of an effective, FDA-approved therapy," Bowlus explained.

For the thousands of people living with PSC, this research represents a significant step forward. Currently, treatment focuses only on managing symptoms and complications, with liver transplantation being the only option for advanced cases. The development of nebokitug offers hope for the first targeted therapy that could actually slow or halt disease progression rather than simply managing its effects.