Topical administration of neuroprotective drugs of no benefit in type 2 diabetes patients
Topically administering the neuroprotective agents brimonidine and somatostatin does not appear to effectively prevent retinal neurodysfunction in patients with type 2 diabetes, according to a study.
The study randomized 449 patients aged between 45 and 75 years with a diabetes duration ≥5 years and an Early Treatment of Diabetic Retinopathy Study (ETDRS) level of ≤35 to receive brimonidine (n=152), somatostatin (n=145) or placebo (n=152).
Outcome investigated was the change in implicit time (IT) assessed by multifocal electroretinography between baseline and at the end of follow-up at 96 weeks. Results failed to show any neuroprotective effect of brimonidine or somatostatin.
Interestingly, in the subgroup of patients with pre-existing retinal neurodysfunction (34.7 percent), IT worsened in the placebo arm (p<0.001) but remained stable in the brimonidine and somatostatin arms.
One serious adverse event considered related to the investigational drugs was reported, namely ocular hyperaemia occurring in the brimonidine arm.
The findings indicate that while eye drops containing neuroprotective agents (brimonidine or somatostatin) are not beneficial in the primary prevention of neurodysfunction or in modulating the appearance and progression of microvascular disease in patients with type 2 diabetes, the drugs appear useful in preventing the worsening of pre-existing retinal neurodysfunction, researchers said.
It is therefore important to screen retinal neurodysfunction and identify a subset of patients in whom neuroprotective treatment might be of benefit, they added.