Faster-acting insulin aspart versus insulin aspart in the treatment of type 1 or type 2 diabetes during pregnancy and post-delivery (CopenFast): an open-label, single-centre, randomised controlled trial

Background Faster-acting insulin aspart (faster aspart) is considered safe for use during pregnancy and breastfeeding but has not been evaluated in this population. We aimed to evaluate the effect of faster aspart versus insulin aspart on fetal growth, in women with type 1 or type 2 diabetes during pregnancy and post-delivery.Methods This open-label, single-centre, superiority trial was conducted at Rigshospitalet, Copenhagen, Denmark. Participants aged 18 years or older with type 1 or type 2 diabetes were stratified by diabetes type and insulin treatment modality (multiple daily injections or insulin pump), randomly assigned 1:1 to faster aspart or insulin aspart, from 8 weeks and 0 days (8+0) of gestation to 13+6 weeks of gestation, and followed up until 3 months post-delivery. Primary outcome was infant birthweight SD score. Secondary outcomes included HbA1c as well as maternal and fetal outcomes in all participants during the trial. This trial is registered with ClinicalTrials.gov, NCT03770767.Findings Between Nov 11, 2019 and May 10, 2022, 109 participants were included in the faster aspart group and 107 in the insulin aspart group. Primary outcome data were available in 203 (94%) of 216 participants, and no participants discontinued treatment during the trial. Mean birthweight SD score was 1 center dot 0 (SD 1 center dot 4) in the faster aspart group versus 1 center dot 2 (1 center dot 3) in the insulin aspart group; estimated treatment difference -0 center dot 22 [-0 center dot 58 to 0 center dot 14]; p=0 center dot 23. At 33 weeks of gestation, mean HbA1c was 42 mmol/mol (SD 6 mmol/mol; 6 center dot 0% [SD 0 center dot 9%]) versus 43 mmol/mol (SD 7 mmol/mol; 6 center dot 1% [SD 1 center dot 2%]); estimated treatment difference -1 center dot 01 (-2 center dot 86 to 0 center dot 83), p=0 center dot 28. No additional safety issues were observed with faster aspart compared with insulin aspart.Interpretation Treatment with faster aspart resulted in similar fetal growth and HbA1c, relative to insulin aspart, in women with type 1 or type 2 diabetes. Faster aspart can be used in women with type 1 or type 2 diabetes during pregnancy and post-delivery with no additional safety issues.

Automated summary

The study found that using faster aspart compared to insulin aspart in pregnant women with diabetes did not pose additional safety issues, and resulted in similar effects on fetal growth and maternal indicators.