MSD's Januvia (sitagliptin) has gained a new licence in the UK for use in people with type 2 diabetes with moderate-to-severe renal impairment.

The new authorisation from the Medicines and Healthcare products Regulatory Agency (MHRA) means that people with sub-optimum kidney function, representing up to a third of all people with diabetes, how have another medicine available to them, says the firm.

The new indication is based on two 54-week studies looking at the efficacy and safety of Januvia versus glipizide in people with type 2 diabetes mellitus (T2D) and moderate-to-severe renal impairment, and in people with T2D and end-stage renal disease (ESRD) on dialysis.

One study compared Januvia at 25mg or 50mg once-daily to glipizide at 2.5mg to 20mg a day and showed a mean reduction in HbA1c of-0.76% with Januvia and -0.64% with glipizide after 54 weeks. The incidence of hypoglycaemia in the Januvia group (6.2%) was lower in comparison to the glipizide group (17%), a statistically significant difference, comments MSD.

The second study, in patients with ESRD on dialysis, showed that treatment with Januvia 25mg once daily for 54 weeks provides clinically-meaningful reductions from baseline in HbA1c (-0.72% with Januvia versus -0.87% with glipizide [difference of 0.15 (95% Cl; -018, 0.49)]). Glipizide starting dose was 2.5 mg qd and titrated up or down to a potential maximum dose of 10mg bid (20mg/day). Fasting plasma glucose was similar to that observed with glipizide.

Januvia was well-tolerated, with a numerically-lower incidence of symptomatic hypoglycaemia in comparison to glipizide; however, the incidence of hypoglycaemia was not significantly different between the treatment groups (Januvia 6.3%; glipizide 10.8%).

If people with T2D have impaired renal function, their kidneys do not filter the blood as efficiently as people with normal kidney function, and these patients can pose a management problem because some diabetes treatments are either unsuitable for them or the dosage must be adjusted dependent upon renal function, commented Dr Donal O'Donoghue, consultant nephrologist and principal investigator for the Greater Manchester Collaboration for Leadership in Applied Health Research (CLAHRC) project chronic kidney disease (CKD) theme at the University of Manchester.

"The sitagliptin licence extension means that patients with advanced renal impairment, stages 4 and 5 CKD can now be controlled with a simple dosage adjustment. For patients with mild renal impairment no dose adjustment s required, which is a real practical benefit," said Dr O'Donoghue.

"One of the main complications of diabetes is kidney disease, or diabetic nephropathy, and this unfortunately develops in up to one-third of all people with diabetes," added Professor John Wilding, head of the department of obesity and endocrinology at the University of Liverpool. 

"Once the kidney are damaged due to high levels of blood glucose, early-stage kidney disease will follow. Control of blood pressure and blood glucose can help reduce the risk of kidney disease in people with diabetes but treatment choices for glucose-lowering treatments are limited because some drugs cannot be used in people with hypoglycaemia. Physicians around the world have been prescribing sitagliptin at 25mg and 50mg in this large patient population for a number of years, so it is pleasing that in the UK we now have the option for dosage adjustment to improve glycaemic control, in renally-compromised patient with a low risk of hypoglycaemia," said Prof Wilding.

2.9 million people in the UK have been diagnosed with diabetes, and an estimated 850,000 people have the condition but are undiagnosed. There are two main types of diabetes - type 1 and type 2 - and type 2 is the most common, accounting for 90% of all people with diabetes, or an estimated 2.61 million people in the UK.