Dual and Triple Mechanisms of Action
Newer agents with double or triple mechanisms of action appear to have a more direct effect on the liver.
“Dual agents may have an added effect by improving MASLD directly through adipose regulation and thermogenesis, thereby improving fibrosis,” Said said.
An example is tirzepatide, a GLP-1 RA and an agonist of glucose-dependent insulinotropic polypeptide (GIP). Like GLP-1, GIP is an incretin. When used together as co-agonists, GLP-1 and GIP have been shown to increase insulin and glucagonostatic response and may work synergistically.
A new phase 2 trial that randomly assigned patients with biopsy-confirmed MASH and moderate or severe fibrosis to receive either once-weekly subcutaneous tirzepatide at one of three doses (5, 10, or 15 mg) or placebo found that tirzepatide at each dosage outperformed placebo in resolution of MASH without worsening of fibrosis.
“These findings were encouraging,” Said said. “We’ll see if the results continue into phase 3 trials.”
The combination of GLP-1 RAs with glucagon (GCG) receptor agonists also has garnered interest.
In a phase 2 trial, adults with biopsy-confirmed MASH and fibrosis stages F1-F3 were randomly assigned to receive either one of three doses of the GLP-1/GCG RA survodutide (2.4, 4.8, or 6 mg) or placebo. Survodutide at each dose was found to be superior to placebo in improving MASH without the worsening of fibrosis, reducing liver fat content by at least 30%, and decreasing liver fibrosis by at least one stage, with the 4.8-mg dose showing the best performance for each measure. However, adverse events, including nausea, diarrhea, and vomiting, were more frequent with survodutide than with placebo.
Trials of triple-action agents (GLP-1/GIP/GCG RAs) are underway too.
The hope is the triple agonists could deliver greater reduction in hepatic fat in patients with MASLD, Sanyal said.
Sanyal further noted that a reduction in liver fat is important, citing a meta-analysis that showed ≥ 30% relative decline in liver fat is associated with higher odds of histologic response and MASH resolution.
Sanyal pointed to efocipegtrutide (HM15211), a GLP-1/GIP/GCG RA, which demonstrated significant liver fat reduction after 12 weeks in patients with MASLD in a phase 1b/2a randomized, placebo-controlled trial and is now in phase 2 development.
Another example is retatrutide (LY3437943), a once-weekly injectable, that was associated with up to a 24.2% reduction in body weight at 48 weeks, compared with 2.1% with placebo, in a phase 2 trial involving patients with obesity.
A sub-study assessed the mean relative change from baseline in liver fat at 24 weeks. These participants, who also had MASLD and ≥ 10% of liver fat content, were randomly assigned to receive either retatrutide in one of four doses (1, 4, 8, or 12 mg) or placebo for 48 weeks. All doses of retatrutide showed significantly greater reduction in liver fat content compared with placebo in weeks 24-48, with a mean relative liver fat reduction > 80% at the two higher doses. Moreover, ≥ 80% of participants on the higher retatrutide doses experienced ≥ 70% reduction in liver fat at 48 weeks, compared with 0% reduction in those on placebo, and hepatic steatosis resolved in > 85% of these participants.
This space “continues to evolve at a rapid rate,” Sanyal said. For example, oral dual-action agents are under development.
