On March 29, the US Food and Drug Administration (FDA) approved the diabetes drug Invokana (generic name canagliflozin) for use, in conjunction with a healthful diet and physical activity, in adults with Type 2 diabetes. It is the first drug in a new class of medicines known as sodium glucose cotransporter 2 (SGLT2) inhibitors.
In the process of filtering the blood, the kidneys typically reabsorb all the filtered glucose and return it to the bloodstream. One of the main proteins responsible for this reabsorption is SGLT2. By inhibiting the action of SGLT2, Invokana blocks the reabsorption of glucose by the kidneys, promoting a loss of glucose in the urine and lowering blood glucose levels.
The recommended starting dose of the drug is 100 milligrams daily, taken before the first meal of the day. In certain people requiring increased blood glucose control, the dose can be increased to up to 300 milligrams daily.
The safety and effectiveness of the medicine were established through nine clinical trials, involving more than 10,285 people with Type 2 diabetes, that showed improvements in fasting blood glucose levels and A1C levels (a measure of blood glucose control over the previous 2–3 months) in those taking Invokana. Clinical trials also showed a reduction in body weight and systolic blood pressure (the top number) in people using the medicine.
The FDA is requiring five trials of Invokana once it is on the market, including one focusing on cardiovascular events; an “enhanced pharmacovigilance program” to monitor malignancies, serious cases of pancreatitis, severe hypersensitivity reactions, photosensitivity reactions (sun allergy), liver abnormalities, and adverse pregnancy outcomes; a bone safety study; and two studies looking at how the drug works and how safe and effective it is in children.
This medicine has been studied as a stand-alone therapy and in combination with Type 2 diabetes treatments such as metformin, insulin, Actos (pioglitazone), and drugs in the sulfonylurea class. It should not be used to treat people with Type 1 diabetes, diabetic ketoacidosis (a potentially life-threatening condition marked by a chemical imbalance in the body), severe kidney impairment, end-stage kidney disease, or those on dialysis. It is not known whether Invokana is safe in children under 18 years of age.
The most common side effects of Invokana are vaginal yeast infection, urinary tract infection, and increased urination. Because of its diuretic effect, Invokana may also cause postural hypotension, or sudden low blood pressure upon standing; this can cause symptoms such as dizziness or fainting, which are most common in the first three months after starting the medicine.
According to an article in The New York Times, the drug will have a wholesale price of $8.77 per tablet, which manufacturer Johnson & Johnson says is competitive with that of some other diabetes drugs.