Effects of the switch from dulaglutide to tirzepatide on glycemic control, body weight, and fatty liver: a retrospective study

Metabolic dysfunction-associated steatotic liver disease: A story of muscle and mass

Skeletal muscle alterations (SMA) are increasingly recognized as both contributors and consequences of metabolic dysfunction-associated steatotic liver disease (MASLD), affecting disease progression and outcomes. Sarcopenia is common in patients with MASLD, with a prevalence ranging from 20% to 40% depending on the population and diagnostic criteria used. In advanced stages, such as metabolic dysfunction-associated steatohepatitis and fibrosis, its prevalence is even higher. Sarcopenia exacerbates insulin resistance, systemic inflammation, and oxidative stress, all of which worsen MASLD. It is an independent risk factor for fibrosis progression and poor outcomes including mortality. Myosteatosis refers to the abnormal accumulation of fat within muscle tissue, leading to decreased muscle quality. Myosteatosis is prevalent (> 30%) in patients with MASLD, especially those with obesity or type 2 diabetes, although this can vary with the imaging techniques used. It reduces muscle strength and metabolic efficiency, further contributing to insulin resistance and is usually associated with advanced liver disease, cardiovascular complications, and lower levels of physical activity. Altered muscle metabolism, which includes mitochondrial dysfunction and impaired amino acid metabolism, has been reported in metabolic syndromes, including MASLD, although its actual prevalence is unknown. Altered muscle metabolism limits glucose uptake and oxidation, worsening hyperglycemia and lipotoxicity. Reduced muscle perfusion and oxygenation due to endothelial dysfunction and systemic metabolic alterations are common in MASLD associated with comorbidities, such as obesity, hypertension, and atherosclerosis. It decreases the muscle capacity for aerobic metabolism, leading to fatigue and reduced physical activity in patients with MASLD, aggravating metabolic dysfunction. Various SMA in MASLD worsen insulin resistance and hepatic fat accumulation, may accelerate progression to fibrosis and cirrhosis, and increase the risk of cardiovascular disease and mortality. Management strategies for SMA include resistance training, aerobic exercise, and nutritional support (e.g., high-protein diets, vitamin D, and omega-3 fatty acids), which are essential for mitigating skeletal muscle loss and improving outcomes. However, pharmacological agents that target the muscle and liver (such as glucagon-like peptide-1 receptor agonists) show promise but have not yet been approved for the treatment of MASLD.

Case Report: Amelioration of severe metabolic dysfunction-associated steatohepatitis after switching from conventional GLP-1RAs to tirzepatide

Metabolic dysfunction-associated steatohepatitis (MASH) has cardiometabolic risk factors, such as obesity and type 2 diabetes, and has been reported to have a potentially higher risk of mortality than conventional steatotic liver diseases. Liver fibrosis develops and can progress to cirrhosis and hepatocellular carcinoma. Although some antidiabetic agents have been reported to ameliorate the condition, no specific medical treatment has been developed to date. Tirzepatide is a dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 (GLP-1) receptor agonist (GLP-1RA) that has shown efficacy against MASH in some clinical trials. However, these trials were limited to those with mild-to-moderate fibrosis and their history of treatment was often unclear. Here, we report the case of a 50-year-old man with a 16-year history of diabetes. He demonstrated poor control of his diabetes with elevated liver enzymes. A liver biopsy was performed and he was diagnosed with steatohepatitis. Liraglutide was administered for 3 years but his liver function and glycemic control deteriorated gradually and a second liver biopsy was performed in 2023. The histological examination found cirrhosis and liraglutide was switched to tirzepatide. Over 6 months of administration of tirzepatide, the patient's glycated hemoglobin and elevated liver enzyme levels improved. A third biopsy was performed, which showed a marked improvement in histology, with the amelioration of liver fibrosis. A diagnosis of steatotic liver disease was made. Although some previous studies had demonstrated an amelioration of liver fibrosis and an improvement in the prognosis of patients following GLP-1RA treatment, effective medications for patients with severe fibrosis or who are refractory to treatment with GLP-1RAs has not been identified to date. We reported a case with severe MASH whose condition had ameliorated by switching from conventional GLP-1RAs to tirzepatide.

Comparison of Dose Escalation Versus Switching to Tirzepatide Among People With Type 2 Diabetes Inadequately Controlled on Lower Doses of Dulaglutide : A Randomized Clinical Trial

BACKGROUND

Tirzepatide, a once-weekly glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist approved for the treatment of adults with type 2 diabetes or obesity, showed clinically meaningful reductions in hemoglobin A1c (HbA1c) and body weight in the SURPASS phase 3 clinical trial program.

OBJECTIVE

To compare efficacy and safety of escalation of dulaglutide dose versus switching to tirzepatide in inadequately controlled type 2 diabetes.

DESIGN

Multicenter, randomized, open-label, phase 4 trial (SURPASS-SWITCH [A Phase 4, Randomized, Open-Label, Active-Controlled Study to Investigate the Efficacy and Safety of Switching from Weekly Dulaglutide to Weekly Tirzepatide in Adults with Type 2 Diabetes], ClinicalTrials.gov: NCT05564039).

SETTING

38 sites across 5 countries.

PARTICIPANTS

Adults with HbA1c 7.0% or greater to 9.5% or less, stable body weight, body mass index of 25 kg/m2 or greater, receiving a stable dose of dulaglutide (0.75 or 1.5 mg) for at least 6 months and 0 to 3 oral antihyperglycemic medications for at least 3 months.

INTERVENTION

Escalation of dulaglutide to 4.5 mg or maximum tolerated dose (MTD) or switching to tirzepatide.

MEASUREMENTS

The primary end point was change from baseline in HbA1c at week 40. The key secondary end point was change from baseline in weight at week 40.

RESULTS

A total of 282 adults were randomly assigned to tirzepatide (n = 139) or dulaglutide (n = 143). Change from baseline in HbA1c at week 40 was -1.44% (SE, 0.07) with tirzepatide, 15 mg or MTD, and -0.67% (SE, 0.08) with dulaglutide, 4.5 mg or MTD (estimated treatment difference, -0.77% [95% CI, -0.98% to -0.56%; P < 0.001]). Change from baseline in weight at week 40 was -10.5 kg (SE, 0.5) with tirzepatide and -3.6 kg (SE, 0.5) with dulaglutide (estimated treatment difference, -6.9 kg [CI, -8.3 to -5.5 kg; P < 0.001]). Serious adverse events were reported by 10 (7.2%) tirzepatide and 10 (7.0%) dulaglutide participants. The most common treatment-emergent adverse events were nausea and diarrhea.

LIMITATION

Open-label design.

CONCLUSION

In SURPASS-SWITCH, switching treatment to tirzepatide provided additional HbA1c reduction and weight loss compared with escalating treatment with dulaglutide.

PRIMARY FUNDING SOURCE

Eli Lilly and Company.

Impacts of tirzepatide on older patients with diminished β-cell function and dementia

Tirzepatide could control postprandial hyperglycemia even in cases with diminished β-cell function. This finding gives new insight into the treatment of older patients with diabetes. However, tilzepatide does not replace basal insulin in cases with diminished β-cell function and requires careful observation for sarcopenia.