Johnson & Johnson's diabetes drug canagliflozin could be facing a delay to market after US regulators voiced concern over the drug's potential heart effects.

A US Food and Drug Administration advisory panel is due to meet later this week to decide on its recommendations to the regulator regarding approval of the drug, which could be the first on the market in a new class of diabetes medicines called sodium-glucose co-transporter 2 (SGLT2) inhibitors. 

But in documents released ahead of that meeting, agency staff note that while canagliflozin seems effective at lowering blood glucose, there could be a higher risk of cardiovascular and bone-related side effects.  

Nine Phase III studies compared canagliflozin to various other diabetes medications, and data indicate that the drug is non-inferior to Merck & Co's Januvia (sitagliptin) and glimepiride in controlling HbA1c.

But its cardiovascular effects are still being assessed in the CANVAS trial, which in the first 30 days showed 13 cardiovascular events in the patients taking the drug versus just one in the placebo arm, FDA staff note.

"It is unclear whether this is a spurious finding or a true increased risk of early CV events with canagliflozin in patients at high risk for CV event," the documents state.

Delay for CV data?

The FDA is expected to announce its decision on canagliflozin's future by the end of March, but according to Wells Fargo Securities analyst Lawrence Biegelsen "we would not be surprised to see FDA wait to review the full CANVAS cardiovascular outcomes study, which should be available this April," media reports note.

Delays to the drug's approval could prevent it from enjoying a first-to-market advantage, particularly with Boehringer Ingelheim and Eli Lilly's SGLT2 inhibitor empagliflozin is snapping at its heals, with a filing expected this year in the USA, Europe and Japan.

It is hoped that the new SGLT2 inhibitor class of drugs might sidestep some of the side effects of current diabetes treatments, such as weight gain or low blood sugar. 

But last year another SGLT2 inhibitor - AstraZeneca and Bristol-Myers Squibb's Forxiga (dapagliflozin) - was rejected by regulators on safety concerns in the US, although it did win clearance in Europe.