Is Tirzepatide the New Game Changer in Type 2 Diabetes?

Abstract

Background: Tirzepatide (TZP) is a once-weekly glucagon-like peptide 1 (GLP-1) and glucose-dependent-insulinotropic-polypeptide (GIP) receptor co-agonist approved for T2D. TZP provides promising evidence in improving glucose control and weight loss in T2D and obesity across preclinical and human studies, including data from the SURPASS program. Aims: The goal of this paper was to review the evidence on TZP in terms of glucose control, body weight, and the progression of chronic diabetes-related complications and comorbidities. Results: The mean change in HbA1c ranged from −1.6% to −2.06% over placebo, from −0.29% to −0.92% over each GLP-1RAs, and from −0.7% to −1.09% over basal insulins. In SURPASS-6, TZP was more effective than insulin lispro U100 added to basal insulin in reducing HbA1c levels at the study end (−2.1% vs. −1.1%, respectively). Compared to placebo, TZP induces a significant weight loss: 7.5 (5 mg/week); 11 (10 mg/week); and 12 kg (15 mg/week). Compared to GLP-1RAs, TZP reduces body weight from −1.68 kg to −7.16 kg depending on the dose (5 to 15 mg, respectively). Compared to basal insulin alone rigorously titrated, TZP added onto basal-insulin results in the best strategy for the composite endpoint of improvement of glucose control and weight loss. In SURPASS-6, TZP compared to insulin lispro U100 in add-on to insulin glargine U100 reduced body weight by 9 kg in mean (versus weight gain in basal-bolus users: +3.2 kg). TZP has pleiotropic effects potentially dampening the individual cardiovascular risk, including a reduction in systolic arterial pressure by 4 to 6 mmHg and total cholesterol by 4–6% compared to baseline. A post hoc analysis of SURPASS-4 revealed that TZP, compared to glargine U100, delayed the rate of glomerular filtration decline (−1.4 mL/min vs. −3.6 mL/min, respectively), reduced the rate of urinary albumin excretion (−6.8% vs. +36.9%, respectively), and was associated with a lower occurrence of the composite renal endpoint (HR 0.58 [0.43; 0.80]). Conclusions: Consistent evidence indicates that TZP dramatically changes the clinical course of T2D in different clinical scenarios. The efficacy and safety of TZP on chronic diabetes-related comorbidities and complications seem promising, but ongoing trials will clarify the real benefits.