Metabolic dysfunction-associated steatohepatitis (MASH) is a leading cause of liver-related mortality, affecting 16 million adults in the United States (US) with prevalence expected to increase over 50% by 2030 [
1]. In March 2024, resmetirom, a thyroid receptor beta agonist, became the first Food and Drug Administration (FDA) accelerated approved drug for MASH treatment. Semaglutide received accelerated approval in August 2025, and 5 other drugs have progressed to phase 3 trials [
2]. While MASH is underdiagnosed and the FDA label covers only stage 2–3 fibrosis, the treatment-eligible population is still estimated to range from 2.3–8.3 million US adults [
3]. Data regarding prescription uptake of resmetirom may inform efforts to optimize access to current and future MASH treatments. To bridge this knowledge gap, we analyzed trends in resmetirom prescriptions between April 2024 to November 2025.
We utilized data from IQVIA’s National Prescription Audit, which covers 92% of prescriptions filled at US retail and mail-order pharmacies, including specialty pharmacies. We enumerated prescription fills (new prescription vs. refill) for resmetirom by channel (retail vs. mail-order pharmacy) and by prescriber specialty (gastroenterologist, hepatologist, primary care physician [PCP], advanced provider practitioner [APP: nurse practitioner or physician assistant], other). Joinpoint regression assessed the monthly percentage change in total prescription fills with 95% confidence intervals with a minimum of two observations between joinpoints. Interrupted time-series analysis assessed immediate changes where the minimum of two observations between joinpoints could not be met to accurately model trends. Specifically, interrupted time-series analysis was used to assess the immediate observed change in July 2025, which approximates the publication [
4] of the pivotal phase 3 trial results in the
New England Journal of Medicine in June 2025 and the FDA announcement of accelerated approval in August 2025 for semaglutide in MASH. Interrupted time-series allowed for generation of a confidence interval and
P-value for this short time-segment in which JoinPoint could not. To ensure robustness of this approach, we performed a sensitivity analysis that applied JoinPoint analysis throughout the study period, rather than interrupted time-series for this short time-segment. Analyses were performed using Joinpoint Regression Program, v5.4.0.0 April 2025 (Statistical Research and Applications Branch, National Cancer Institute) and Stata/MP v17.0 (StataCorp LLC, College Station, TX, USA).
Total monthly resmetirom prescriptions fills increased between April 2024 to June 2025 (from 122 to 9425), and then rapidly decreased and stabilized at 4,000 per month through November 2025. Throughout the study period, mail-order accounted for over 77% of total fills (
Fig. 1). Trends for new monthly prescriptions and refills were similar to total fills (
Fig. 1). New prescriptions represented a larger share of total fills at the beginning of the study period, but refills comprised the majority by August 2024. In total, there were 32,053 new prescriptions, with most prescribed by gastroenterologists (42.8%), followed by APPs (41.6%), hepatologists (7.3%), PCPs (6.8%), and other providers (1.4%) (
Fig. 1).
Joinpoint regression identified 3 initial time periods between April to June 2025 with distinct slopes in monthly percentage change in total prescription fill trends: (i) April-August 2024 with a marked increase (+89.2% fills/month; 95% CI, 48.0–141.9,
P<0.001); (ii) September 2024 – February 2025 with an attenuated increase (+14.2% fills/month; 95% CI 9.7–18.8,
P<0.001); (iii) March-June 2025 with a plateau (-0.4% fills/month; 95% CI -9.4 to +9.4,
P=0.92) (
Fig. 1). This was followed in July 2025 by a sharp decrease in monthly total prescriptions fills (-4,692 fills in one month; 95% CI -5,955 to -3,428,
P<0.001) based on the interrupted time-series analysis. In our sensitivity analysis that applied JoinPoint throughout the study period, the estimated change in monthly total prescription fills was -51.7% fills/month for July 2025, similar to the results of the interrupted time-series analysis. Subsequently, the monthly percentage change stabilized through November 2025 (-1.3% fills/month; 95% CI -9.8 to +7.9,
P=0.66).
After accelerated FDA-approval of resmetirom in March 2024, there was a marked increase in resmetirom prescriptions until a plateau in March 2025, followed by a sharp decrease in July 2025, coinciding in time between the publication [
4] of the pivotal phase 3 trial results in the
New England Journal of Medicine and the FDA announcement of accelerated approval of semaglutide for MASH. This plateau is within the time range experienced by other new drugs [
5]. Despite this increase, total new prescriptions represent only 1.4% of the estimated treatment-eligible population even using restrictive eligibility criteria [
3]. While not wellreported across new drugs, this treatment-eligible population penetration is lower than SGLT-2 inhibitors, which reached an estimated penetration of 7% at plateau [
6]. Given the recent semaglutide approval, appraisal of first-in-disease drug diffusion trends is informative. This study highlights that even with new drugs that have efficacy and are generally well-tolerated, as is the case with resmetirom, access to MASH treatment may have considerable barriers.
The relatively limited resmetirom use is likely multifactorial. The list price of resmetirom ($47,000/year) could be a barrier without adequate insurance. Prescribing initiation may be deterred by off-label incretin (e.g., semaglutide) use, and liver fibrosis staging which may be challenging to access or interpret [
2].
This study identifies an area for actionable change. Over 92% of prescriptions were from gastroenterologists/hepatologists and APPs. We suspect APPs were mostly from gastroenterology/hepatology practices because APPs with majority hepatology practice outnumber hepatologists [
7], and the number of PCPs prescribing resmetirom was low. Only 6.8% of prescriptions were from PCPs, which was stable through most of the study. Prescribing dependent mostly on specialists seems suboptimal as many patients with MASH, especially without cirrhosis, are seen by PCPs and endocrinologists, rather than gastroenterologists/hepatologists [
7]. In preparation for MASH treatments that may achieve full FDA approval, these results highlight the need for care pathways that are more practical to use, for specialists and non-specialists alike, particularly in the setting of widespread incretin use.
This study had limitations. Resmetirom is a new drug and our study period was relatively short. Resmetirom is a firstin-disease drug, so we lacked a comparison group. Although high use of off-label incretin use may limit generalizability to other diseases, these findings are still pertinent to MASH, which has a number of other drugs that are anticipated to be approved by regulators in the near future. Our dataset lacked granularity regarding insurance, type of APP, geography, individual-level out-of-pocket cost and variables. Resmetirom prescriptions may be underreported, although this data source encompasses 92% of national prescriptions, including specialty pharmacies. Future studies should use longer-term granular data to inform policies that optimize access to new MASH treatments.
FOOTNOTES
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Authors’ contributions
Study concept and design (BPL, CS); data acquisition (BPL, DMQ); data analysis and interpretation (BPL, CS, JLD); drafting of manuscript (BPL); critical revision and approval of manuscript (BPL, CS, MD, JLD, NAT, DMQ).
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Acknowledgements
This study is based on IQVIA National Prescription Audit obtained under license from IQVIA’s information services.
The statements, findings, conclusions, views, and opinions contained and expressed herein are not necessarily those of IQVIA or any of its affiliated or subsidiary entities.
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Conflicts of Interest
BPL reports consulting for Altimmune, GlaxoSmithKline, Novo Nordisk. The authors otherwise have no conflicts of interests directly related to contents of manuscript.
Figure 1.Trends in resmetirom prescription fills by fill type and prescriber between April 2024 and November 2025.
Abbreviations
advanced provider practitioner
Food and Drug Administration
metabolic dysfunction-associated steatohepatitis
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Citations
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, Christopher Scannell2, Matt Dukewich1, Jennifer L. Dodge1,3, Norah A. Terrault1, Dima Mazen Qato2,3,4
