On January 11, an advisory panel recommended that the FDA approve Johnson & Johnson’s SGLT-2 inhibitor, Invokana (canagliflozin). The panel voted 10-5 in favor of approving the drug for type 2 diabetes. Though the FDA does not have to follow the advisory committee’s recommendation, it typically does. A final approval decision by the FDA is expected within the next two months. As discussed in this issue’s learning curve, SGLT-2 inhibitors improve blood glucose control by causing the kidneys to excrete any excess glucose in urine.
Though the panel’s ultimate decision was to approve Invokana, its members had two main concerns that will likely influence the final approval and label (the label is all the fine print that explains which patients should or should not take the drug, the various details about how well the drug works, the risks involved in taking the drug as assessed by FDA, etc.). First, in clinical trials, Invokana did not have the same effect for patients who have completely healthy kidneys as those patients who have impaired kidney function – that means kidney problems. On average, the drug significantly lowered patients’ A1cs by 0.6-1.2% from an average baseline of 8% without any risk of hypoglycemia. However, the A1c reductions drop to just 0.3-0.4% for patients with impaired kidney function. By the end of the discussion, the panel agreed that there should be restrictions on prescribing the drug to this group of patients, since the efficacy is lower with the same or even more side effects. There was no consensus on what kidney function threshold (known as estimated glomerular filtration rate, or eGFR) should be used to determine eligibility for the drug. Should the drug be approved, we expect the final label will include at least some restriction in this regard.
The second area of heated discussion concerned the potential cardiovascular risks of Invokana.
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