Background: This pilot study evaluated whether adding phentermine to liraglutide would induce further weight loss in participants who had previously lost weight with liraglutide alone.
Subjects/methods: Participants were 45 adults with obesity (75.6% female, 55.6% white, body mass index = 34.3 ± 4.7 kg/m2) who had lost an average of 12.6 ± 6.8% of initial weight during a prior 1-year randomized trial with liraglutide and intensive behavioral treatment. Participants were re-randomized, in a double-blinded fashion, to liraglutide 3.0 mg plus phentermine 15.0 mg (liraglutide-phentermine) or liraglutide plus placebo (liraglutide-placebo). Participants also were provided with four, 15-minute counseling sessions during the 12-week extension study.
Results: At week 12, the liraglutide-phentermine and liraglutide-placebo groups lost a mean (±SEM) of 1.6 ± 0.6% and 0.1 ± 0.5% of re-randomization weight, respectively (p = 0.073). Two (9.1%) liraglutide-phentermine participants and one (4.3%) liraglutide-placebo participant lost ≥5% of re-randomization weight; 19 (86.4%) and 16 (69.9%) participants, respectively, maintained their full weight loss achieved in the prior 1-year trial (p = 0.125). Liraglutide-phentermine participants generally reported larger reductions in hunger and food preoccupation than liraglutide-placebo participants during the first 8 weeks of the extension study.
Conclusions: The combination of liraglutide and phentermine appeared to be well-tolerated but did not produce additional clinically meaningful weight loss in individuals who had already lost 12.6% of initial weight with liraglutide alone.
Trial registration: ClinicalTrials.gov number, NCT02911818.
Keywords: Anti-obesity medication; Lifestyle modification; Weight management.
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