Effect of Bimagrumab vs Placebo on Body Fat Mass Among Adults With Type 2 Diabetes and Obesity: A Phase 2 Randomized Clinical Trial

Abstract

Importance: Antibody blockade of activin type II receptor (ActRII) signaling stimulates skeletal muscle growth. Previous clinical studies suggest that ActRII inhibition with the monoclonal antibody bimagrumab also promotes excess adipose tissue loss and improves insulin resistance.

Objective: To evaluate the efficacy and safety of bimagrumab on body composition and glycemic control in adults with type 2 diabetes and overweight and obesity.

Design, setting, and participants: This double-masked, placebo-controlled, 48-week, phase 2 randomized clinical trial was conducted among adults with type 2 diabetes, body mass index between 28 and 40, and glycated hemoglobin (HbA1c) levels between 6.5% and 10.0% at 9 US and UK sites. The trial was conducted from February 2017 to May 2019. Only participants who completed a full treatment regimen were included in analysis.

Interventions: Patients were randomized to intravenous infusion of bimagrumab (10 mg/kg up to 1200 mg in 5% dextrose solution) or placebo (5% dextrose solution) treatment every 4 weeks for 48 weeks; both groups received diet and exercise counseling.

Main outcomes and measures: The primary end point was least square mean change from baseline to week 48 in total body fat mass (FM); secondary and exploratory end points were lean mass (LM), waist circumference (WC), HbA1c level, and body weight (BW) changes from baseline to week 48.

Results: A total of 75 patients were randomized to bimagrumab (n = 37; 23 [62.2%] women) or placebo (n = 38; 12 [31.6%] women); 58 (77.3%) completed the 48-week study. Patients at baseline had a mean (SD) age of 60.4 (7.7) years; mean (SD) BMI of 32.9 (3.4); mean (SD) BW of 93.6 (14.9) kg; mean (SD) FM of 35.4 (7.5) kg; and mean (SD) HbA1c level of 7.8% (1.0%). Changes at week 48 for bimagrumab vs placebo were as follows: FM, -20.5% (-7.5 kg [80% CI, -8.3 to -6.6 kg]) vs -0.5% (-0.18 kg [80% CI, -0.99 to 0.63 kg]) (P < .001); LM, 3.6% (1.70 kg [80% CI, 1.1 to 2.3 kg]) vs -0.8% (-0.4 kg [80% CI, -1.0 to 0.1 kg]) (P < .001); WC, -9.0 cm (80% CI, -10.3 to -7.7 cm) vs 0.5 cm (80% CI, -0.8 to 1.7 cm) (P < .001); HbA1c level, -0.76 percentage points (80% CI, -1.05 to -0.48 percentage points) vs -0.04 percentage points (80% CI, -0.23 to 0.31 percentage points) (P = .005); and BW, -6.5% (-5.9 kg [80% CI, -7.1 to -4.7 kg]) vs -0.8% (-0.8 kg [80% CI, -1.9 to 0.3 kg]) (P < .001). Bimagrumab's safety and tolerability profile was consistent with prior studies.

Conclusions and relevance: In this phase 2 randomized clinical trial, ActRII blockade with bimagrumab led to significant loss of FM, gain in LM, and metabolic improvements during 48 weeks in patients with overweight or obesity who had type 2 diabetes. ActRII pathway inhibition may provide a novel approach for the pharmacologic management of excess adiposity and accompanying metabolic disturbances.

Trial registration: ClinicalTrials.gov number: NCT03005288.

Conflict of interest statement

Conflict of Interest Disclosures: Dr Heymsfield reported receiving personal fees from Tanita and Medifast outside the submitted work. Drs Coleman, Miller, Rooks, Roubenoff, Laurent, Praestgaard, Petricoul, and Swan reported being employees of Novartis Institutes for BioMedical Research during the conduct of the study. Drs Coleman and Roubenoff reported having a patent for PAT058683-US-PSP pending with Novartis. Drs Rooks and Roubenoff reported being coauthors of a patent for use of bimagrumab in other indications that is no longer being developed. Dr Goodpaster reported receiving personal fees from Novartis for work performed during the conduct of the study. No other disclosures were reported.

Figures

Figure 1.. Trial Design, Screening, Randomization, and Treatment

ADA indicates American Diabetes Association; EoS, end of study; EoT, end of treatment; PD, pharmacodynamics; and PK, pharmacokinetic. aFive patients had dosage capped. bPK visits.

Figure 2.. Effect of Bimagrumab on Total Body Fat Mass

1 participant in the bimagrumab group did not have a week 48 or end of study (EOS) dual-energy x-ray absorptiometry scan performed. aP < .001.