Phentermine and Topirimate for Type 2 Diabetes Patients
In two randomized, double-blind and placebo-controlled studies, the safety and efficacy of treatment with phentermine (PHEN) and topiramate ER (TPM ER) (Qsymia) plus lifestyle for weight loss and glycemic benefits were measured. The studies included obese/overweight adults with type 2 diabetes.
In the OB-202 study, subjects were randomized at a 1:1 ratio to receive placebo or active treatment. The active treatment group received 15mg of phentermine once daily in the morning and 100mg of topiramate ER in the afternoon. There was a 4 week titration to the randomized dosage, followed by an additional 24 weeks of treatment. All subjects who completed the OB-202 study were eligible to continue for an additional 28 weeks in the DM-230 study for a total treatment period of 56 weeks. The active treatment group in the DM-230 study were given once daily capsule containing a combination treatment of PHEN/TPM ER 15mg/92mg in the morning. The primary end point was to measure the change in HbA1C level. The life style modifications and comorbidities of all subjects were managed to the standard of care.
Out of the 210 subjects, 165 subjects completed the OB-202 study. The most common reason for cessation was due to non-compliance. Out of 165 subjects who completed the OB-202 study, 130 enrolled in the DM-230 study (55 in the placebo group, 75 in the PHEN/TPM ER 15/92mg group). Out of 165 subjects who enrolled in the DM-230 study, 92.3% completed the study. The common reason for cessation from the DM-230 study was loss to follow-up. At baseline, subjects had an average weight of 94.9kg, BMI of 35.5 kg/m2, and over 60% were taking two or more drugs to treat their diabetes.
At the end of the study, average weight loss in the active therapy group was 9.6% (~9kg) and 2.7% in the placebo group with a p-value of (P < 0.0001 vs. placebo). HbA1C level decreased in both groups. However, active group’s HbA1c decreased more compared to placebo group (-1.2% vs. -1.6%, P=0.038). A total of 53% who received active treatment with PHEN/TPM ER 15/92mg demonstrated HbA1C ≤7.0% compared to placebo group with only 40%. Adverse events included paresthesia, constipation, and insomnia.
The authors concluded that PHEN/TPM ER 15/92mg plus lifestyle modification can effectively help weight loss and improve glycemic control for obese/overweight patients with type 2 diabetes.