This week, the U.S. Food and Drug Administration (FDA) approved Janumet, a pill that combines the two previously approved Type 2 diabetes drugs sitagliptin (brand name Januvia) and metformin (Glucophage and other names). Janumet is manufactured by Merck & Co., Inc., and is expected to be available in pharmacies nationwide soon.
Treatment with Janumet is meant to help control blood glucose levels in people with Type 2 diabetes who either have not achieved good control with metformin or sitagliptin alone or who already take both metformin and sitagliptin. Janumet should be taken twice a day with meals and will cost $4.86 per day.
A recent study of Janumet’s effectiveness involved 701 people who had mildly to moderately elevated HbA1c levels (a measure of blood glucose control over time) despite taking metformin. The participants were randomly assigned to receive sitagliptin or a placebo (inactive pill) in addition to their metformin. Neither the participants nor the researchers knew who received the drug and who received the placebo.
After 24 weeks, the participants who received metformin plus sitagliptin (the combination found in Janumet) had HbA1c levels 0.7% lower than those who had received metformin plus placebo. In fact, 47% of people who took metformin plus sitagliptin achieved the American Diabetes Association–recommended HbA1c goal of less than 7% compared to only 18% of those who took metformin plus placebo. People who took metformin plus sitagliptin also experienced lower postmeal blood glucose levels than those who took metformin plus placebo. Both groups experienced similar amounts of weight loss (about 1.5 pounds), and similar low rates of hypoglycemia (low blood glucose), edema, and gastrointestinal reactions (such as diarrhea, nausea, vomiting, or stomach pain).
The components of Janumet work together to control blood glucose levels through multiple mechanisms. Sitagliptin blocks a certain enzyme, which in turn helps increase the pancreas’s production and secretion of insulin and block the liver’s production of glucose. (For more information about how sitagliptin works, please see the blog entry “New Diabetes Drug Januvia Approved by FDA”.) Metformin makes the body’s cells more sensitive to insulin and also lowers the liver’s production of glucose.
Janumet should not be taken by people who have kidney or liver disease, and people who begin Janumet therapy should have their kidney function checked before starting and annually as long as they are taking the drug. Like metformin alone, Janumet carries the very small but serious risk of lactic acidosis, a condition in which lactic acid builds up in the blood, depriving the body’s tissues of oxygen. This condition, which can be fatal, is more likely to occur in people who have kidney disease, liver disease, congestive heart failure, or who drink a high number of alcoholic beverages. These people should not take metformin-containing drugs such as Janumet.