The fixed combination of phentermine/topiramate extended release (PHEN/TMP ER), is marketed in the US as the anti-obesity drug Qsymia.
Now a paper by Timothy Garvey and colleagues, published in Diabetes Care, describes the weight-lowering and anti-diabetic effect of this drug combination in individuals with type 2 diabetes.
The investigators studied the effect of 56-week treatment in 130 participants randomised either to placebo or PHEN/TPM ER (15 mg/92 mg) once-daily with change in A1c levels as the primary endpoint. Both treatment groups also received lifestyle interventions to improve diet and physical activity.
The authors also present data on a secondary analysis of individuals with type 2 diabetes (n=388), who participated in the CONQUER trial.
At week 56 individuals on PHEN/TMP ER lost about 9.4% compared to a 2.7% on placebo. This reduction in body weight was associated with a 1.6% reduction in A1c levels on PHEN/TMP ER compared to a reduction of 1.2% in participants on placebo.
In addition, greater numbers of patients randomized to receive PHEN/TPM ER treatment achieved HbA1c targets with reduced need for diabetes medications when compared with the placebo group.
As expected from these drugs, the most common adverse events included paraesthesia, constipation, and insomnia.
As the authors conclude, PHEN/TPM ER plus lifestyle modification can effectively promote weight loss and improve glycemic control as a treatment approach in obese/overweight patients with type 2 diabetes.
PHEN-TMP ER is currently not approved for obesity management outside the US.
disclaimer: I have served as a paid consultant and speaker for Vivus, the maker of Qsymia.
Garvey WT, Ryan DH, Bohannon NJ, Kushner RF, Rueger M, Dvorak RV, & Troupin B (2014). Weight-Loss Therapy in Type 2 Diabetes: Effects of Phentermine and Topiramate Extended-Release. Diabetes care PMID: 25249652