SAT-LB022 Effects of Intermittent Versus Continuous Phentermine Therapy on Weight Reduction and Inflammatory Markers in Obese Non-diabetic Patients

Introduction: Intermittent phentermine therapy has been proposed as an alternative to overcome tolerance associated with continuous daily use of phentermine to promote greater weight loss. Aim: To compare the effects of intermittent versus continuous phentermine therapy on weight reduction, cardiometabolic profile, inflammatory and anti-inflammatory markers in obese non-diabetic patients. Methods: Non-diabetic obese adults [body mass index (BMI) 27.5 to 35kg/m(2)] were recruited from obesity clinic. Eligible subjects were randomized to receive either continuous phentermine (30mg daily) or intermittent phentermine therapy (30mg daily for 4 weeks alternate with 2 weeks of treatment-free periods) for a total of 24 weeks, in addition to lifestyle modification (comprising of calorie restriction of 1200 kcal per day and at least 150 minutes per week of moderate intensity exercise). Primary endpoints were change in body weight from baseline as well as proportion of subjects losing at least 5% and 10% of baseline body weight at week 24 respectively. Results: Thirty-eight subjects [86.8% females, median age 36.5 years (interquartile range, IQR 32, 41.3), BMI 31.8kg/m(2) (IQR 30.4, 33.4) and waist circumference 94.9cm (IQR 90.2, 99.1)] were randomised to either continuous (n=19) or intermittent phentermine arm (n=19). Fourteen subjects in the former and all in the latter completed the study. There were no significant differences in the degree of weight reduction [ - 7.3 kg (IQR - 10.1, - 3.4) vs - 9.7 kg (IQR -11.2, -7.2), p=0.10] as well as the proportion of subjects who achieved at least 5% and 10% of weight loss (78.9% vs 94.7%, p=0.34; 47.4% vs 73.7%, p=0.18 respectively) at week 24 in both arms. Nonetheless, intermittent phentermine therapy resulted in greater decrease in waist circumference while continuous phentermine therapy produced greater reduction in fasting insulin, homeostasis model assessment of insulin resistance (HOMA-IR) and high-sensitivity C-reactive protein (hsCRP). Both regimes reduced the prevalence of insulin resistance and showed no difference in reduction of the proportion of subjects with high cardiovascular risk (as defined by hsCRP > 3mg/L). No significant between-group differences were seen in changes of blood pressure, pulse rate, glycaemic indices, lipids, adiponectin, binge eating scale scores and 36-item Short Form Survey version 2 (SF-36v2) scores. The most common side effects were dry mouth and insomnia. There was no difference in the occurrence of adverse events between the 2 treatment arms. Conclusion: Intermittent phentermine therapy is as effective as conventional daily phentermine treatment in promoting weight reduction while having similar side effect profile. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.