Estimation of the Eligible Population For Resmetirom Among Adults in the United States for Treatment of Non-Cirrhotic NASH with Moderate-to-Advanced Liver Fibrosis.

Estimation of the treatment-eligible population for resmetirom depends importantly on NASH diagnosis rates, which are predicted to be < 15% in the 3 years after drug approval. Nonalcoholic steatohepatitis (NASH) is an advanced form of nonalcoholic fatty liver disease. Previously there were no treatments for NASH in the United States (US), but as of March 2024, the US Food and Drug Administration (FDA) approved resmetirom (REZDIFFRA™), a once-daily, oral therapy, in conjunction with diet and exercise, under accelerated approval for the treatment of adults (aged 18 years or older) with non-cirrhotic NASH with moderate-to-advanced liver fibrosis (MALF), consistent with stages F2-F3. It is not well understood how many diagnosed patients with NASH would be eligible for treatment with resmetirom; thus, this study aimed to estimate the size of the US resmetirom treatment-eligible population. To do so, we created a flexible population calculator that considers how many people have NASH, what proportion would be eligible for resmetirom treatment-i.e., have non-cirrhotic NASH with MALF-and of those how many people would be diagnosed. We used published literature, screening guidelines, resmetirom study criteria, and analyses of national surveys to inform our range of estimates. In the main analysis, we modeled a NASH prevalence of 4.6% (range 1.3-14.2%), which was then limited to the proportion estimated to have non-cirrhotic NASH with MALF (i.e., 35%) and diagnosed (i.e., 10%, range 3.3-14.3%). A year-over-year growth of approximately 16% in the treatment-eligible population was modeled in years following approval. Assuming a population of 1 million commercial insurance enrollees, the resmetirom treatment-eligible population was estimated to be 1255-1699 in Years 1-3 following approval. We assessed alternative scenarios and have compared our results to existing models.