Journal-based CME Course: Effect of Subcutaneous Tirzepatide vs Placebo Added to Titrated Insulin Glargine on Glycemic Control in Patients With Type 2 Diabetes

Activity ID

11299

Expires

February 8, 2025

Format Type

Journal-based

CME Credit

1

Fee

$30

CME Provider: JAMA

Description of CME Course

Importance  The effects of tirzepatide, a dual glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 receptor agonist, as an addition to insulin glargine for treatment of type 2 diabetes have not been described.

Objective  To assess the efficacy and safety of tirzepatide added to insulin glargine in patients with type 2 diabetes with inadequate glycemic control.

Design, Setting, and Participants  Randomized phase 3 clinical trial conducted at 45 medical research centers and hospitals in 8 countries (enrollment from August 30, 2019, to March 20, 2020; follow-up completed January 13, 2021) in 475 adults with type 2 diabetes and inadequate glycemic control while treated with once-daily insulin glargine with or without metformin.

Interventions  Patients were randomized in a 1:1:1:1 ratio to receive once-weekly subcutaneous injections of 5-mg (n = 116), 10-mg (n = 119), or 15-mg (n = 120) tirzepatide or volume-matched placebo (n = 120) over 40 weeks. Tirzepatide was initiated at 2.5 mg/week and escalated by 2.5 mg every 4 weeks until the assigned dose was achieved.

Main Outcomes and Measures  The primary end point was mean change from baseline in glycated hemoglobin A_1c (HbA_1c) at week 40. The 5 key secondary end points included mean change in body weight and percentage of patients achieving prespecified HbA_1c levels.

Results  Among 475 randomized participants (211 [44%] women; mean [SD] age, 60.6 [9.9] years; mean [SD] HbA_1c, 8.31% [0.85%]), 451 (94.9%) completed the trial. Treatment was prematurely discontinued by 10% of participants in the 5-mg tirzepatide group, 12% in the 10-mg tirzepatide group, 18% in the 15-mg tirzepatide group, and 3% in the placebo group. At week 40, mean HbA_1c change from baseline was −2.40% with 10-mg tirzepatide and −2.34% with 15-mg tirzepatide vs −0.86% with placebo (10 mg: difference vs placebo, −1.53% [97.5% CI, −1.80% to −1.27%]; 15 mg: difference vs placebo, −1.47% [97.5% CI, −1.75% to −1.20%]; P < .001 for both). Mean HbA_1c change from baseline was −2.11% with 5-mg tirzepatide (difference vs placebo, −1.24% [95% CI, −1.48% to −1.01%]; P < .001]). Mean body weight change from baseline was −5.4 kg with 5-mg tirzepatide, −7.5 kg with 10-mg tirzepatide, −8.8 kg with 15-mg tirzepatide and 1.6 kg with placebo (5 mg: difference, −7.1 kg [95% CI, −8.7 to −5.4]; 10 mg: difference, −9.1 kg [95% CI, −10.7 to −7.5]; 15 mg: difference, −10.5 kg [95% CI, −12.1 to −8.8]; P < .001 for all). Higher percentages of patients treated with tirzepatide vs those treated with placebo had HbA_1c less than 7% (85%-90% vs 34%; P < .001 for all). The most common treatment-emergent adverse events in the tirzepatide groups vs placebo group were diarrhea (12%-21% vs 10%) and nausea (13%-18% vs 3%).

Conclusions and Relevance  Among patients with type 2 diabetes and inadequate glycemic control despite treatment with insulin glargine, the addition of subcutaneous tirzepatide, compared with placebo, to titrated insulin glargine resulted in statistically significant improvements in glycemic control after 40 weeks.

Trial Registration  ClinicalTrials.gov Identifier: NCT04039503

Disclaimers

1. This activity is accredited by the American Medical Association.
2. This activity is free to AMA members.

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