The US Food and Drug Administration (FDA) has issued a Complete Response Letter (CRL) for Sanofi’s type I diabetes drug, Zynquista (sotagliflozin).

Developed in partnership with Lexicon Pharmaceuticals, the drug is an investigational dual inhibitor of SGLT-1 and SGLT-2, proteins that influence how the intestines and kidneys process blood sugar (glucose), which is used for the treatment of adults with the disorder in combination with insulin.

It was accepted for review by The European Medicines Agency in March 2018, after results came back from the inTandem clinical trial programme, in which three Phase III clinical trials assessed the drug’s safety and efficacy in around 3,000 adults with the poorly controlled type I diabetes.

In the trials a glycated haemoglobin level lower than 7% was recorded at week 24, with no episodes of severe hypoglycaemia or diabetic ketoacidosis after randomisation, compared to the placebo group (28.6% versus 15.2%).

Despite the positive results, in trials a higher risk of developing diabetic ketoacidosis (DKA) was seen in patients on the combination compared to insulin alone, even though patients and physicians were given advice about avoiding the side effect, and FDA committee members said they were concerned it could be a bigger problem in real-world use.

The FDA advisory panel was split directly in half on whether or not to recommend approval of the drug, with eight voting for and eight against.