Madrigal Pharmaceuticals, Inc. announced data from multiple resmetirom abstracts presented at the European Association for the Study of the Liver's International Liver Congress (EASL 2022), including a late-breaking presentation of data from the Phase 3 MAESTRO-NAFLD-1 study and three additional oral presentations from the resmetirom clinical development program. Primary and key secondary endpoints from the double-blind, placebo-controlled, 969-patient MAESTRO-NAFLD-1 safety study were achieved; resmetirom was safe and well tolerated and provided significant reductions in liver fat (measured using magnetic resonance imaging proton density fraction (MRI-PDFF) and FibroScan controlled attenuation parameter (CAP)), LDL-C, and other atherogenic lipids vs placebo. Patients treated with resmetirom also achieved significant reductions relative to placebo in ALT, AST, and GGT.

For those patients with sufficient baseline liver stiffness, as measured by FibroScan vibration-controlled transient elastography (VCTE) or magnetic resonance elastography (MRE), responder analyses showed statistically significant VCTE and MRE responses in the resmetirom groups compared to placebo. Adverse event-related withdrawals were uncommon in the MAESTRO-NAFLD-1 study. The most common adverse event reported with greater frequency in the resmetirom groups vs placebo was generally mild diarrhea or increased stool frequency at the beginning of therapy.

105 patients with well-compensated NASH cirrhosis were enrolled in the open-label arm of the MAESTRO-NAFLD-1 study. Baseline FibroScan VCTE (kPa 24.6) and MRE (5.7) scores were consistent with F4 fibrosis. Patients with lower MRI-PDFF (=5%) at baseline had more progressed cirrhosis and greater spleen volumes.

Similar to patients with non-cirrhotic NASH, liver volume was greatly elevated compared to normal at baseline. Resmetirom reduced MRI-PDFF and LDL-C and other atherogenic lipids in patients with NASH cirrhosis and reduced FibroScan controlled attenuation parameter (CAP), VCTE, and MRE in a significant fraction of patients. The reduction in FibroScan VCTE (mean reduction of 9 kPa) occurred in the more advanced group (baseline PDFF =5%).

Similar improvements were observed in MRE. 73% of patients, independent of baseline cirrhosis severity, had at least 15% reduction in liver volume at Week 52. Spleen volume was also reduced and was strongly correlated with liver volume change and exposure to resmetirom.

Reductions in liver enzymes and atherogenic lipids were similar across patient subgroups. Resmetirom was safe and well tolerated. As observed in patients with noncirrhotic NASH, mild GI adverse events were seen at the beginning of therapy.

No differences in safety parameters between patients with cirrhosis compared to noncirrhotic NASH patients were noted. No thyroid axis changes or hyper- or hypothyroid symptoms were observed. Abstracts from the resmetirom development program provide new insights to inform noninvasive testing strategies, improve artificial intelligence-based evaluation of treatment response, and better characterize the cost burden of NASH.

Oral presentation: “Utility of FIB-4 thresholds to identify patients with at-risk F2-F3 NASH based on screening data from a 2,000 patient biopsy confirmed cohort of resmetirom Phase 3 clinical trial, MAESTRO-NASH” (OS101). Oral presentation: “Impact of resmetirom-mediated reductions in liver volume and steatosis compared with placebo on the quantification of fibrosis using second harmonic generation in a serial liver biopsy study” (OS030). Poster: “Retrospective AI-based measurement of NASH histology (AIM-NASH) analysis of biopsies from Phase 2 study of Resmetirom confirms significant treatment-induced changes in histologic features of nonalcoholic steatohepatitis” (SAT094).

Poster: “A higher FIB-4 score is associated with higher healthcare costs and hospitalizations in patients with nonalcoholic steatohepatitis” (THU094). Madrigal is currently conducting two Phase 3 clinical trials, MAESTRO-NASH and MAESTRO-NAFLD-1, to demonstrate the safety and efficacy of resmetirom for the treatment of NASH. MAESTRO-NASH is a multicenter, randomized, double-blind, placebo-controlled Phase 3 study of resmetirom in patients with liver biopsy-confirmed NASH and was initiated in March 2019.

The study targeted enrollment of 900 patients with biopsy-proven NASH (fibrosis stage 2 or 3, at least 450 fibrosis stage 3), randomized 1:1:1 to receive once-daily resmetirom 80 mg, resmetirom 100 mg, or placebo. After 52 weeks of treatment, a second biopsy is performed. The dual primary surrogate endpoints on biopsy are NASH resolution with =2-point reduction in NAS (NAFLD Activity Score), and with no worsening of fibrosis OR a 1-point decrease in fibrosis with no worsening of NASH.

Either primary endpoint can be achieved for a successful trial outcome. A key secondary endpoint is lowering of LDL-C. The planned target enrollment was announced as completed on June 30, 2021. The first 900 patients in the MAESTRO-NASH study will continue on therapy after the initial 52-week treatment period; up to another 1,100 patients are to be added using the same randomization plan.

The study is expected to continue for up to 54 months to accrue and measure hepatic clinical outcome events including progression to cirrhosis on biopsy (52 weeks and 54 months) and hepatic decompensation events. MAESTRO-NAFLD-1 was initiated in December 2019 and the 52-week multicenter, randomized, double-blind, placebo-controlled Phase 3 study of resmetirom in over 1,200 patients with NAFLD, presumed NASH, has completed the double-blind arms and an open-label 100 mg arm. An additional open-label active treatment arm in patients with early (well-compensated) NASH cirrhosis is ongoing.

The primary endpoint is to evaluate the safety and tolerability of resmetirom. An open-label extension study (MAESTRO-NAFLD-OLE) is ongoing. Patients in the 52-week blinded phase of MAESTRO-NAFLD-1 were randomized 1:1:1:1 to receive once-daily resmetirom 80 mg, resmetirom 100 mg, placebo or a resmetirom 100 mg in an open-label arm.

MAESTRO-NAFLD-1 (unlike MAESTRO-NASH), did not include a liver biopsy and represents a “real-life” NASH study. Patients with 3 metabolic risk factors were documented with NASH or NAFLD by historical liver biopsy or noninvasive techniques. Using noninvasive measures, MAESTRO-NAFLD-1 was designed to provide incremental safety information to support the NASH indication as well as provide additional data regarding clinically relevant key secondary efficacy endpoints to better characterize the potential clinical benefits of resmetirom on cardiovascular- and liver-related endpoints.