5 Promising MASH Therapies That Could Follow Madrigal’s Rezdiffra

 When Madrigal Pharmaceuticals’ Rezdiffra was approved last month as the first-ever treatment for metabolic dysfunction-associated steatohepatitis, experts hailed the drug as an “important first.” However, the consensus among experts is that Rezdiffra is just the beginning for a disease that has been notoriously difficult to treat.

Metabolic dysfunction-associated steatohepatitis (MASH) is inflammation of the liver caused by excess fat cells, which can lead to progressive fibrosis and cirrhosis of the liver. “[Rezdiffra] is the first oral drug that’s been demonstrated to show reversal of fibrosis in Phase III clinical studies,” said Lawrence Blatt, CEO of Aligos Therapeutics, which is also developing a candidate for MASH. “If you look at the magnitude of the impact of Madrigal’s drug, it’s good for patients,” he told BioSpace. “I don’t want to downplay what they’ve achieved . . . but there’s a lot of room for improvement.” About a quarter of patients treated with Rezdiffra have an improvement in fibrosis, he noted. “That leaves 75% of patients with the need for better therapies.”

A day before Rezdiffra’s approval, Ionis Pharmaceuticals announced that its own metabolic dysfunction-associated steatohepatitis (MASH) candidate hit the primary endpoint in a Phase II trial, showing significant improvement in steatohepatitis without worsening fibrosis, according to the company.

And this is only the tip of the iceberg. Here, BioSpace looks at five mid- to late-stage investigational MASH drugs.

Ionis’s ION224

The FDA asks MASH drug developers to show in Phase III clinical trials a one-stage improvement in fibrosis (ranked on a scale from F0, or the absence of fibrosis, to F4, full-blown cirrhosis) with no worsening of MASH, or the resolution of MASH with no worsening of fibrosis. Ionis appears to be well on its way to this metric, as 32% of people in the high dose arm of its Phase II trial of ION224 had at least a one-stage improvement in fibrosis without worsening of steatohepatitis as measured by biopsy, compared to 12.5% of patients in the placebo cohort.

The drug was safe and well-tolerated in the trial, Ionis stated, and there was a lower rate of early termination in the ION224 study arms compared to placebo.

ION224 is designed to cut production of DGAT2, an enzyme that studies have linked to fatty liver disease. The Phase II trial “is the first to demonstrate clinical evidence that the reduction of hepatic fat after DGAT2 inhibition correlates with improvements in MASH histological endpoints,” Rohit Loomba, a professor of medicine and chief of the division of gastroenterology and hepatology at the University of California San Diego, said in a company statement. 

Altimmune’s Pemvidutide

Pemvidutide, developed by Altimmune and currently entering Phase IIb trials, is a peptide-based GLP-1/glucagon dual receptor agonist. While activation of the GLP-1 receptors leads to appetite suppression, activation of glucagon increases energy expenditure, both of which are important for weight loss. Glucagon is also believed to have direct effects on hepatic fat metabolism, leading to rapid reductions in levels of liver fat and serum lipids, according to Altimmune.

Mayank Mamtani, head of healthcare research at B. Riley Securities, is bullish on therapies targeting the glucagon receptor to treat MASH. In addition to pemvidutide, he cited Eli Lilly’s retatrutide and Boehringer Ingelheim’s survodutide. “If you look at [these programs], they’re telling you that this is the drug class that’s going to win in MASH.” On top of a “profound” lowering of liver fat, he said there are other benefits with this drug class, including lowering of liver enzymes and cholesterol, “that you’re not getting from Madrigal.” Boehringer Ingelheim reported positive data from its own Phase II trial in February.

So far in clinical trials, once weekly pemvidutide has shown “compelling weight loss, robust reductions in triglycerides, LDL cholesterol, liver fat content and blood pressure,” and a clean safety profile, according to Altimmune. Topline 24-week data from the Phase II IMPACT trial is due in the first quarter of 2025.

89bio’s Pegozafermin

San Francisco–based 89bio is one of a handful of companies developing an analog of FGF21, a hormone that may address underlying metabolic issues that drive liver and cardiometabolic diseases, including MASH.

The primary unmet need in MASH is in more advanced disease, Mamtani said. “Something that works in F4 is obviously the holy grail,” he said, adding that analogs of fibroblast growth factor 21 (FGF21) could have potential here.

In November 2023, 89bio announced positive topline data from its Phase IIb trial of pegozafermin. After 48 weeks, MASH patients with stage F2 or F3 fibrosis treated with the candidate saw sustained, statistically significant improvements across liver fat and noninvasive tests of liver injury/inflammation and fibrosis.

Pegozafermin is “the first FGF21 analog candidate to demonstrate positive, sustained benefits over a 48-week period in patients with advanced NASH,” Hank Mansbach, the company’s chief medical officer, said in a statement at the time. (MASH used to be known by the name nonalcoholic steatohepatitis, or NASH.) Patients with stage F2 and F3 fibrosis are at high risk of progression to cirrhosis and increased risk of liver cancer, liver decompensation and death.

Viking Therapeutics’ VK2809

Currently in Phase IIb trials, Viking Therapeutics’ VK2809 belongs to the same thyroid hormone receptor beta (THR-β) class as Rezdiffra. William Blair analysts Andy Hsieh and Alexandra Ramsey wrote in a March 2024 note that the drug could “potentially outshine Rezdiffra’s clinical profile.”

Topline data presented in May 2023 showed VK2809 cleared the trial’s primary endpoint, significantly reducing liver fat in patients with biopsy-confirmed MASH. After 12 weeks, patients treated with 2.5 mg of Viking’s candidate saw a 45.3% decrease in liver fat content, compared to 3.7% in placebo comparators. Updated results from the Phase IIb study demonstrated “robust and comparable liver fat reductions among patients with or without type II diabetes, as well as patients with either F2 or F3 fibrosis,” Viking reported in November 2023.

Viking expects 52-week biopsy results during the first half of this year.

Aligos Therapeutics’ ALG-055009

Earlier this month, Aligos initiated dosing in the Phase IIa HERALD study of ALG-055009, also a THR-ß agonist. The placebo-controlled trial will enroll approximately 100 individuals with presumed MASH and F1–F3 fibrosis.

So far in clinical trials, Blatt said ALG-055009 is showing up to 100-fold more potency than Rezdiffra. He added that, in contrast to Rezdiffra, the drug has linear and non-variable pharmacokinetics, “so it’s very well controlled.”

With Rezdiffra, “the variation they see among these individuals is highly variable, so some people are getting the optimal dose, some people are getting underdosed [and] some people might be getting overdosed,” Blatt explained, even though they all got the same amount of the drug. He added that only about 25% of patients taking Rezdiffra had improvement in fibrosis because “you have a lot of patients who were underexposed to the drug, and they weren’t receiving the amount of drug that they needed.”

Topline safety and efficacy data from the HERALD trial are expected in Q4, 2024.

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