Chemomab Therapeutics has achieved a significant breakthrough in its development program for nebokitug (CM-101), securing FDA alignment on a single Phase 3 registration trial design for treating Primary Sclerosing Cholangitis (PSC). This development marks a crucial step toward potentially delivering the first FDA-approved therapy for this devastating liver disease.
The agreement, reached during an End-of-Phase 2 Meeting with the FDA, establishes a clear regulatory pathway that could significantly accelerate the drug's journey to market. The Phase 3 trial design eliminates the need for invasive liver biopsies and additional confirmatory studies, focusing instead on clinically meaningful disease progression events.
"This is a huge achievement for Chemomab, for patients, and for the larger community combatting PSC," said Dr. Adi Mor, CEO of Chemomab. "The design allows us to significantly accelerate the potential timeline to full approval since there is no need for additional confirmatory studies."
Phase 3 Trial Design and Endpoints
The pivotal trial will enroll approximately 350 PSC patients, with participants receiving either 20 mg/kg of nebokitug or placebo intravenously every three weeks in a 2:1 ratio. The primary endpoint focuses on time-to-first clinical event, encompassing various disease progression indicators such as:
- Acute cholangitis
- Biliary strictures requiring intervention
- Portal hypertension
- Hepatic decompensation
- Elevated MELD score
- Liver transplantation
- Cholangiocarcinoma
- Death
Clinical Significance and Expert Perspective
Dr. Christopher Bowlus, Chief of Gastroenterology and Hepatology at UC Davis School of Medicine, emphasized the trial's importance: "Until now, the pathway to drug approval in PSC has been problematic due to the lack of validated surrogate endpoints. This design enhances our chances of efficiently and accurately identifying the potential clinical benefits of this promising new drug."
Mechanism of Action and Previous Results
Nebokitug is a first-in-class dual activity monoclonal antibody targeting CCL24, a protein crucial in inflammatory and fibrotic pathways. The drug has demonstrated favorable safety profiles in clinical trials, including the Phase 2 SPRING trial, where patients with moderate to advanced disease showed improvements across multiple disease-related endpoints.
Market Impact and Future Plans
PSC affects approximately 30,000 patients in the U.S. and 80,000 worldwide, with no currently approved therapies. The condition often leads to liver failure and increases cancer risk, accounting for about half of PSC-related deaths.
Chemomab is currently engaged in discussions with potential strategic partners while preparing for the Phase 3 program launch, potentially before year-end. The company expects to report topline data from the open-label extension of the SPRING trial by the end of the first quarter.
Dr. Matt Frankel, Chemomab's Chief Medical Officer, noted that the trial design could support global marketing authorizations beyond the U.S., potentially leading to a broad label in PSC. The company continues to benefit from strong relationships with global clinical investigators developed during its successful Phase 2 SPRING study, which should facilitate enrollment in the upcoming pivotal trial.
