The US Food and Drug Administration has finally approved AstraZeneca's diabetes drug Farxiga but is insisting on six post-marketing studies, including a cardiovascular outcomes trial.

The approval was expected given that the agency's Endocrinologic and Metabolic Drugs Advisory Committee voted 13-1 last month that the benefits of Farxiga (dapagliflozin), already marketed in Europe as Forxiga, outweigh identified risks. The FDA rejected the drug in January 2012 due to concerns about possible liver damage and the potential link with breast and bladder cancer.

The drug is a sodium-glucose co-transporter 2 (SGLT2) inhibitor that blocks the reabsorption of glucose by the kidney, increases glucose excretion and lowers blood glucose levels. It was co-developed with Bristol-Myers Squibb but last month AstraZeneca bought out the latter's stake in their diabetes joint venture for $2.7 billion upfront and regulatory- and sales-based milestone payments of up to $1.4 billion, plus royalties.

Curtis Rosebraugh, director of the Office of Drug Evaluation II in the FDA’s Center for Drug Evaluation and Research, said that controlling blood sugar levels "is very important in the overall treatment and care of diabetes, and Farxiga provides an additional treatment option for millions of Americans._ _The agency notes that Farxiga is not recommended for patients with active bladder cancer and is requiring six post-marketing studies, one which will evaluate its cardiovascular risk and two to assess the drug in paediatric patients.

Farxiga will compete with Johnson & Johnson's recently-approved SGLT2 inhibitor Invokana (canagliflozin) and analysts believe these class of drugs will be blockbusters.