Extreme caution on the use of sirolimus for the congenital hyperinsulinism in infancy patient.

We have recently published on the limited effectiveness of sirolimus as a treatment option for hypoglycaemia as a consequence of hyperinsulinism. Our data oppose the view that mTOR inhibitors provide new opportunities for the treatment of patients with hyperinsulinism. We are not convinced by the argument that any benefit for some patients outweighs the potential and later long-term problems that accompany mTOR inhibition in the neonate. We also express the opinion that caution must be taken when repurposing/repositioning therapies in the field of rare disease.