San Diego, CA — 2/18/26 — Model Medicines, an AI-native biotechnology company, today announced that it will present first-in-category hepatic antiviral data on MDL-001 at the 2026 Conference on Retroviruses and Opportunistic Infections (CROI). 

The data will be presented during the session “Beyond the C: Hepatitis D, B, and E”. Model Medicines will highlight MDL-001’s potent pan-hepatic antiviral activity across Hepatitis C virus (HCV), Hepatitis B virus (HBV), and Hepatitis D virus (HDV), including clinically challenging viral co-infections HCV/HBV and HBV/HDV.

Poster Details

• Conference: CROI 2026

• Session: “Beyond the C: Hepatitis D, B, and E”

• Title: #589 - “MDL-001, a Novel Oral Thumb-1 Polymerase Inhibitor, Shows Efficacy in HCV/HBV In Vitro and In Vivo”

• Date: February 23, 2026

• Time: 2:30 PM – 4:00 PM (Mountain Time)

The Urgent Unmet Need in Viral Hepatitis

Chronic viral hepatitis is a global crisis of staggering scale. The World Health Organization (WHO) estimates that 254 million people live with chronic hepatitis B and approximately 58 million with chronic hepatitis C. Chronic viral hepatitis is responsible for roughly 1.3 million deaths annually, making it the second deadliest communicable disease worldwide. 

Persons carrying multiple hepatitis viruses represent the most dangerous and least served populations. An estimated 12–72 million individuals globally carry HDV, a satellite virus that cannot replicate without concurrent HBV infection. 5–15 million carry HBV/HCV co-infection., Only 13% of HBV infections and approximately 36% of HCV infections are diagnosed globally. The vast majority of co-infected patients remain “untreated and unaware” according to the WHO. In the United States, fewer than 22% of HBV-positive patients are ever screened for HDV. The substantial population of undiagnosed and untreated individuals strongly suggests that the true patient population is considerably larger than current estimates reflect.

The clinical consequences of co-infection are severe. HBV/HDV co-infection drives progression to cirrhosis in 70–80% of patients within 5–10 years. Fifteen percent of patients develop cirrhosis within 1-2 years. HDV co-infection carries a 3.8-fold increased risk of liver-related mortality, a 2–3-fold increased risk of hepatocellular carcinoma, and up to a 7-fold increased risk of liver transplantation compared to HBV alone. HCV/HBV co-infection is similarly devastating. Co-infected patients face a 3.6-fold increased risk of liver cancer compared to HBV monoinfection, with cirrhosis incidence rates nearly three times higher. 

The current standard-of-care paradigm introduces a dangerous paradox. HCV approved Direct-Acting Antivirals (DAAs) can trigger HBV reactivation upon HCV viral clearance due to the loss of HCV-mediated suppression of HBV. The FDA issued a black box warning on all approved DAAs in October 2016 after reports of severe HBV reactivation, including fatal cases. In the case of HDV, the current therapeutic standard includes older, toxic pegylated interferon-alpha (PEG-IFN-α) with low efficacy. The EMA-approved bulevirtide requires indefinite administration, is not curative and is unavailable in the U.S. 

MDL-001 A Pan-Hepatic Therapeutic Strategy

MDL-001 is an oral, direct-acting, non-nucleoside inhibitor of viral polymerases designed to engage a conserved biological choke point shared across viral families. This mechanism enables MDL-001 to function as a pan-hepatic antiviral, with the potential to simplify treatment paradigms for patients infected with multiple hepatitis viruses.

“Patients with chronic hepatitis co-infections are among the most difficult to treat and the least well served by current therapies,” said Daniel Haders, PhD, Founder and CEO of Model Medicines. “The data we are presenting at CROI demonstrate for the first time that a single, oral, direct-acting antiviral can be engineered to address multiple liver viruses and their co-infections, something that has not been achievable with traditional discovery approaches.”

The data being presented at CROI demonstrate that MDL-001:

• Exhibits direct-acting antiviral activity across multiple hepatic viruses, including HCV, HBV, and HDV
  
  

• Maintains activity in HCV/HBV and HBV/HDV co-infection models, two of the most clinically severe and underserved patient populations

Advancing Toward the Clinic

MDL-001 has demonstrated broad preclinical efficacy across hepatic and respiratory viruses and is advancing through IND-enabling studies. Model Medicines’ virology program is designed to support first-in-class and potentially best-in-class antiviral candidates that can be deployed across diverse patient populations and disease settings.