A Dual Action Approach to Treating MASH

Episode Summary

Executive Summary: This episode explains MASH, a common but underdiagnosed progressive fatty liver disease, and 89Bio’s lead asset pegzafermin, an FGF21 analog designed to address both liver fibrosis and metabolic dysfunction. CEO Rohan Pellikar argues current approved therapies help some patients but leave major unmet need in advanced fibrosis/cirrhosis, where combination or more potent therapies may be required.

Main Topics: What MASH is and why it matters (Priority: 5/5): Pellikar describes MASH as a chronic, progressive fatty liver disease driven by fat accumulation, inflammation, fibrosis, and potentially cirrhosis, with major overlap with obesity, diabetes, and dyslipidemia. Diagnosis challenges and under-recognition (Priority: 5/5): The conversation highlights that MASH is often asymptomatic for years, is usually found through abnormal liver tests and metabolic risk factors, and is officially biopsy-diagnosed though imaging is used in practice. Disease burden and epidemiology (Priority: 5/5): The interview emphasizes the scale of MASH in the U.S., its rising incidence, and its role as a major cause of liver transplant and potential contributor to hepatocellular carcinoma. Limitations of approved therapies (Priority: 4/5): Rohan reviews the newly approved treatments, resmetirom and semaglutide, noting they produce only moderate fibrosis benefits and do not cure disease, leaving substantial unmet need especially in advanced fibrosis. Pegzafermin mechanism and clinical rationale (Priority: 5/5): Pegzafermin is presented as an engineered FGF21 analog intended to lower liver fat, improve insulin sensitivity and lipids, and directly affect fibrotic pathways, thereby targeting both liver and systemic metabolic drivers. Clinical results and development strategy (Priority: 4/5): The company reports phase 2B signals in F2/F3 MASH and phase 2 benefits in severe hypertriglyceridemia, with ongoing phase 3 studies in both non-cirrhotic and cirrhotic MASH and in SHTG. Commercialization and financing outlook (Priority: 3/5): Pellikar says 89Bio intends to build a commercial organization but remains open to partnerships, especially outside the U.S., and expects current cash to fund near-term readouts but not the full MASH development program.

Key Arguments: MASH is common, progressive, and often missed early because symptoms are absent or nonspecific, making underdiagnosis a major public-health issue. The greatest unmet need is in F3/F4 patients, especially cirrhosis, where current therapies have limited efficacy or no demonstrated benefit. Approved drugs such as resmetirom and semaglutide provide only moderate fibrosis improvements, so combination therapy is likely to be the future standard. Pegzafermin is differentiated because it targets both the liver and the underlying metabolic abnormalities that drive disease progression. The company’s phase 2 data suggest pegzafermin can reverse fibrosis in some patients and prevent progression in others over 24 weeks. The same biology may translate into severe hypertriglyceridemia, where pegzafermin showed large triglyceride reductions and broader metabolic benefits. 89Bio believes longer trials may show stronger effects because fibrosis remodeling takes time, and the liver can regenerate once injurious drivers are reduced.

Data Points: Name change: 2023 - The disease was referred to as NASH until 2023, when it became MASH (metabolic dysfunction-associated steatohepatitis). U.S. burden: Millions of people - MASH affects millions in the United States and incidence continues to rise. Liver transplant contribution: One of the leading causes - MASH is now among the leading causes of liver transplantation in the U.S. Progression rate: About one-third - Pellikar said roughly one-third of people with fatty liver disease progress to MASH. Diagnostic delay: 10-15 years - Patients may remain undetected for many years because early MASH is often asymptomatic. Projected U.S. prevalence by 2030: Close to 27 million - A study cited in the interview estimated U.S. MASH prevalence could reach this level by 2030. Advanced fibrosis estimate by 2030: 7.5-8 million - Of the projected 27 million Americans with MASH, this many may have advanced fibrosis. Resmetirom fibrosis benefit: 10%-12% placebo-adjusted - Described as a moderate effect on fibrosis, the key marker of progression. Semaglutide (Wegovy) fibrosis benefit: 14% placebo-adjusted - Also characterized as modest and not adequate for all patients. Fibrosis stages: F0, F1, F2, F3, F4 - Pellikar explained staging, with F4 corresponding to cirrhosis. Pegzafermin phase 2B population: ~220 patients - The NEJM-published study enrolled MASH patients with F2 or F3 fibrosis. Pegzafermin efficacy window: 24 weeks - Robust fibrosis improvement was observed over six months. Pegzafermin fibrosis improvement: >20% placebo-adjusted - Pellikar said the drug showed disease reversal in some patients on a placebo-adjusted basis. Liver fat reduction: 50%-60% - Pegzafermin reduced liver fat in the phase 2 study. SHTG threshold: >500 mg/dL - Defined as severe hypertriglyceridemia. SHTG prevalence in U.S.: 3.5-4 million - Pellikar said this condition is more common than many think. Diagnosed SHTG patients: 1.8 million - Roughly half of U.S. SHTG patients are diagnosed. Triglyceride reduction with pegzafermin: 57%-63% - Observed in eight weeks in patients with triglycerides above 500 mg/dL. Company cash: $561 million - Cash position at the end of June, used to describe runway through near-term readouts.

Pivotal Quotes: "it represents a severe form of metabolic dysregulation, fatty liver disease" — Rohan Pellikar: Defining MASH and explaining it as a progressive metabolic liver disorder. "the biggest unmet need where there's the greatest burden of the disease is these patients with advanced fibrosis and cirrhosis" — Rohan Pellikar: Explaining which patient groups need better therapies most urgently. "we were actually reversing the disease in other patients" — Rohan Pellikar: Describing pegzafermin’s phase 2 fibrosis findings.

Implications: MASH treatment is shifting from lifestyle-only care to a multi-drug era, but advanced fibrosis and cirrhosis remain the key battleground. If pegzafermin’s phase 3 data hold up, it could become a major add-on or combination therapy for high-risk liver and cardiometabolic patients.