Cost-effective drug therapy for the leading cause of childhood blindness
Retinopathy of prematurity is the leading cause of childhood blindness worldwide. It occurs primarily in infants of low birth weight as in the case of premature delivery. This retinal disorder causes loss of vision due to disorganized growth of the blood vessels of the retina. The retina is a membrane that lines the back of the eye which receives the images formed by the lens.
An immature retina of babies born before 7.5 months of gestation forms dilated veins and tortuous arteries leading to scarring and hardening, which eventually cause the retina to detach.
In a multicenter clinical trial led by the University of Texas and participated in by 14 other hospitals, the use of intravitreal bevacizumab, a blood vessel growth inhibitor drug, is being compared with conventional laser treatment. Infants at 30 weeks of gestation or less were examined (low birth weight at 1500g or less).
Infants with acute retinopathy, which is the most difficult to treat (zone I and posterior zone II) and has a high incidence of treatment failure, received either the drug treatment or laser therapy.
Outcomes of the 143 studied infants, published in The New England Journal of Medicine, revealed that retinopathy recurred in 6 percent of patients who were treated with intravitreal bevacizumab and in 42 percent of those who received laser treatment.
The researchers saw mild structural abnormality in just one eye of 31 infants who received the drug, whereas they found mild structural defect in 16 eyes and severe damage in 2 eyes (retinal detachment) of 33 infants who had undergone laser treatment.
Lead author Dr. Helen A. Mintz-Hittner, an attending physician at Children's Memorial Hermann Hospital said that, compared with the conventional laser treatment, the drug therapy has a reduced rate of recurrence and does the best job of preserving vision. It is also inexpensive and there's no more need to intubate the baby. The procedure is quick, results are also seen within hours and recovery is faster.
The authors stressed, though, that timing is critical and that drug therapy at stage 3+ of the disease (dilated veins and tortuous arteries) is the ideal for treatment. They also emphasized the importance of careful follow-up for any recurrence for at least 16 weeks following the injection.