Two dose-ranging studies with PF-04937319, a systemic partial activator of glucokinase, as add-on therapy to metformin in adults with type 2 diabetes.

To assess the efficacy and safety of a range of doses of a systemic, partial, glucokinase activator, PF-04937319, as add-on therapy to metformin, in patients with type 2 diabetes mellitus (T2DM). Patients were randomized to once-daily PF-04937319 doses of 10, 50, 100 mg, or matching placebo (Study B1621002); or PF-04937319 doses of 3, 20, 50, 100 mg, or matching placebo (Study B1621007). Titrated glimepiride (Study B1621002) or sitagliptin (Study B1621007) were included in a double-dummy manner. The primary measure was change from baseline in glycated haemoglobin (HbA1c) at week 12. Key secondary measures included other glycaemic variables and safety and tolerability. In the 639 patients randomized, the minimally efficacious PF-04937319 dose was identified as 50 mg once daily. At the highest PF-04937319 dose tested (100 mg), on average, a clinically significant reduction in HbA1c [-4.94 or -5.11 mmol/mol (-0.45 or -0.47%), placebo-adjusted], which was similar to that achieved with sitagliptin [-4.69 mmol/mol (-0.43%)] but lower than that achieved with titrated glimepiride [-9.07 mmol/mol (-0.83%)], was observed. At this dose, the effect on fasting plasma glucose was not consistent between the two studies (Study B1621002 vs Study B1621007: placebo-adjusted mean change of -0.83 vs +0.50 mmol/l). PF-04937319 was well tolerated at doses up to 100 mg. Hypoglycaemia was reported in 2.5% of patients (on placebo), 5.1% of patients (on PF-04937319 100 mg), 1.8% of patients (on sitagliptin) and 34.4% of patients (on titrated glimepiride). In patients on metformin monotherapy, the addition of a 100-mg dose of PF-04937319 improved glycaemic control and was well tolerated.