WEIGHT LOSS WITH LIRAGLUTIDE 3.0 mg VERSUS PLACEBO FOR INDIVIDUALS WHO ADHERE TO THE TRIAL DRUG

A SECONDARY ANALYSIS FROM SCALE IBT

Abstract

INTRODUCTION
The objective of the SCALE IBT trial was to compare the weight loss of liraglutide 3.0 mg to placebo, both in combination with 56 weeks of intensive behavior therapy (IBT). The primary outcomes of the study were assessed in the intention-to-treat sample, regardless of individuals’ medication adherence. The weight loss estimated in the primary analysis, regardless of drug adherence, was 7.5% versus 4.0% for liraglutide 3.0 mg and placebo, respectively, reflecting a treatment difference favoring liraglutide 3.0 mg of 3.5% (95% CI: 1.6%; 5.3%; p=0.0003). In this pre-specified secondary analysis, we sought to determine the expected effect of liraglutide 3.0 mg on weight loss, as compared to placebo, if all randomized individuals had adhered to study drug for 56 weeks.

METHODOLOGY
A total of 282 individuals with obesity (BMI ≥30 kg/m2 ) were randomized in a 1:1 ratio to 56 weeks of IBT combined with daily injections of either liraglutide 3.0 mg or placebo. The weight loss, based on the assumption that all individuals adhered to the medication, was estimated using two different approaches. The first approach (mixed model repeated measures; MMRM) estimated the weight loss that would have been achieved if all individuals adhered to the trial drug by utilizing information from individuals still on drug after the point of a given individual’s discontinuation to provide a (counter-factual) weight change as if the individual in question had not discontinued the drug. The second (covariate) approach used a regression model to calculate the weight change of individuals with full adherence to trial drug by including adherence as a moderator of the effect of treatment condition on weight change.

RESULTS AND DISCUSSION
The MMRM approach yielded a weight loss difference of 4.6% (95% CI: 2.6%; 6.5%; p<0.0001), and the covariate approach yielded a weight loss difference of 4.6% (95% CI: 2.8%; 6.5%; p<0.0001), with both estimates favoring liraglutide 3.0 mg.

CONCLUSION
The estimated placebo-subtracted weight loss for liraglutide at week 56 of approximately 4.6% in medicationadherent individuals therefore indicates that underlying assumptions are robust. We believe this finding is an important supplement to the study’s primary outcome and can inform practitioners’ expectations when prescribing liraglutide 3.0 mg in combination with IBT for 56 weeks.