Glucagon-like peptide-1 (GLP-1) receptor agonists are an effective treatment option for patients with type 2 diabetes
- act by stimulating insulin secretion in hyperglycemic states, suppressing glucagon secretion in hyperglycemic or euglycemic states, delaying gastric emptying, decreasing appetite, and reducing body weight
Tirzepatide
- is a dual glucose-dependent insulinotropic polypeptide-GLP-1 receptor agonist
- structure is primarily based on the glucose-dependent insulinotropic polypeptide amino acid sequence and includes a C20 fatty diacid moiety
- C20 fatty di-acid moiety that prolongs the duration of action, thus allowing once-weekly subcutaneous administration
- is a 39 amino acid synthetic peptide with agonist activity at both the glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) receptors, with a greater affinity to GIP receptor
- GIP, unlike GLP-1, it is glucagonotropic in a glucose-dependent manner
- the efficacy and safety of once-weekly tirzepatide was compared with semaglutide, a selective GLP-1 receptor agonist (1)
- estimated mean change from baseline in the glycated hemoglobin level was -2.01 percentage points, -2.24 percentage points, and -2.30 percentage points with 5 mg, 10 mg, and 15 mg of tirzepatide, respectively, and -1.86 percentage points with semaglutide
- reductions in body weight were greater with tirzepatide than with semaglutide (least-squares mean estimated treatment difference, -1.9 kg, -3.6 kg, and -5.5 kg, respectively; P<0.001 for all comparisons)
- most common adverse events were gastrointestinal and were primarily mild to moderate in severity in the tirzepatide and semaglutide groups (nausea, 17 to 22% and 18%; diarrhea, 13 to 16% and 12%; and vomiting, 6 to 10% and 8%, respectively). Of the patients who received tirzepatide, hypoglycemia (blood glucose level, <54 mg per deciliter) was reported in 0.6% (5-mg group), 0.2% (10-mg group), and 1.7% (15-mg group); hypoglycemia was reported in 0.4% of those who received semaglutide
- concluded that patients with type 2 diabetes, tirzepatide was noninferior and superior to semaglutide with respect to the mean change in the glycated hemoglobin level from baseline to 40 weeks
- tirzepatide for weight loss
- in SURMOUNT-1
- double-blind, randomized, controlled trial
- assigned 2539 adults with a body-mass index (BMI; the weight in kilograms divided by the square of the height in meters) of 30 or more, or 27 or more and at least one weight-related complication, excluding diabetes, in a 1:1:1:1 ratio to receive once-weekly, subcutaneous tirzepatide (5 mg, 10 mg, or 15 mg) or placebo for 72 weeks, including a 20-week dose-escalation period
- baseline, the mean body weight was 104.8 kg, the mean BMI was 38.0, and 94.5% of participants had a BMI of 30 or higher
- mean percentage change in weight at week 72 was -15.0% (95% confidence interval [CI], -15.9 to -14.2) with 5-mg weekly doses of tirzepatide, -19.5% (95% CI, -20.4 to -18.5) with 10-mg doses, and -20.9% (95% CI, -21.8 to -19.9) with 15-mg doses and -3.1% (95% CI, -4.3 to -1.9) with placebo (P<0.001 for all comparisons with placebo)
- 50% (95% CI, 46 to 54) and 57% (95% CI, 53 to 61) of participants in the 10-mg and 15-mg groups had a reduction in body weight of 20% or more
- most common adverse events with tirzepatide were gastrointestinal, and most were mild to moderate in severity, occurring primarily during dose escalation
- study authors concluded:
- "..In this 72-week trial in participants with obesity, 5 mg, 10 mg, or 15 mg of tirzepatide once weekly provided substantial and sustained reductions in body weight.."
- in SURMOUNT-2
- 72-week trial in adults living with obesity and type 2 diabetes
- once-weekly tirzepatide 10 mg and 15 mg provided substantial reduction in bodyweight (4)
- mean change in bodyweight at week 72 with tirzepatide 10 mg and 15 mg was -12.8% and -14.7% , respectively, and -3.2% with placebo
In the UK, tirzepatide is now approved for use in adults with a BMI of 30kg/m² or more (obesity), as well as those with a BMI between 27-30kg/m² (overweight) who also have weight-related health problems such as prediabetes, high blood pressure, high cholesterol, or heart problems (5)
- is advised that obese or overweight female patients using oral contraceptives should consider using a barrier method of contraception or switching to a non-oral contraceptive method for 4 weeks after starting tirzepatide and for 4 weeks after each increase in dose as it may affect efficacy of the contraceptive pill
- starting dose is 2.5mg once a week for four weeks, increasing to 5mg once a week
- dose may then be increased in at least 4-week intervals up to the maximum dose of 15mg once weekly
A review noted (2):
- Tirzepatide is a novel incretin-based therapy for T2DM
- showed robust HbA1c (-1.94%), FSG (-54.7 mg/dl), and body weight (-8.5 kg) reductions, without an increased risk of hypoglycemia
- at the highest dose (15 mg), tirzepatide reduced: HbA1c (-2.1%), FSG (-61.1 mg/dl), and body weight (-8.6 kg)
Reference:
- Frias JP et al;SURPASS-2 Investigators. Tirzepatide versus Semaglutide Once Weekly in Patients with Type 2 Diabetes. N Engl J Med. 2021 Jun 25.
- Bhagavathula AS, Vidyasagar K, Tesfaye W. Efficacy and Safety of Tirzepatide in Patients with Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Randomized Phase II/III Trials. Pharmaceuticals (Basel). 2021;14(10):991. Published 2021 Sep 28. doi:10.3390/ph14100991
- Jastreboff AM, Aronne LJ, Ahmad NN, Wharton S, Connery L, Alves B, Kiyosue A, Zhang S, Liu B, Bunck MC, Stefanski A; SURMOUNT-1 Investigators. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022 Jun 4. doi: 10.1056/NEJMoa2206038. Epub ahead of print. PMID: 35658024
- Garvey WT et al. Tirzepatide once weekly for the treatment of obesity in people with type 2 diabetes (SURMOUNT-2): a double-blind, randomised, multicentre, placebo-controlled, phase 3 trial. Lancet June 26, 2023
- MHRA (November 8th 2023). MHRA authorises diabetes drug Mounjaro (tirzepatide) for weight management and weight loss