A clinical study testing an infusion of mecasermin rinfabate (“iPlex” or “SHP607”), a drug combination of insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein-3 (IGFBP-3), for the treatment of retinopathy of prematurity (ROP), has failed to meet its primary end-point of reducing the severity of ROP, compared to standard neonatal care. Summary data from the 4-year phase II double-blind controlled study (NCT01096784) were released in July by the sponsor company, Shire Pharmaceuticals (LSE:SHP; NASDAQ:SHPG). According to the company, a proportion of infants receiving the drug showed clinically relevant effects compared to untreated infants on a number of secondary endpoints, including the incidence of severe bronchopulmonary dysplasia and the incidence of severe intraventricular hemorrhage. Following release of the data Shire stated it would meet with the regulator to discuss a potential phase III program for SHP607 focused on complications of prematurity.
The experimental treatment for ROP had been obtained by Shire following their acquisition of a Swedish company, Premacure AB, in March 2013. The drug had orphan drug designation in the EU and was originally developed by INSMED Corporation for the treatment for growth failure in children with primary IGF-1 deficiency. The treatment has been associated or tested with several other disorders including amyotrophic lateral sclerosis, myotonic muscular dystrophy, HIV-associated adipose redistribution syndrome and myotonia congenital.
The study had enrolled 121 premature infants which had been born between 23 and 28 weeks gestation. Once-daily 250 μg/kg IV SHP607 was administered as a continuous infusion from the day of birth out to the gestational age of 30 weeks. The primary endpoint was the severity of ROP as compared to the severity of ROP in an untreated control population while secondary outcome measures included time to discharge from neonatal intensive care, development of bronchopulmonary dysplasia, body weight, brain development as assessed by changes in head circumference and brain volume and other clinical measurements. According to the company, summary results indicated that SHP607 reduced the incidence of severe bronchopulmonary dysplasia and the incidence of severe intraventricular hemorrhage, compared to standard neonatal care. In addition, no treatment-related deaths or serious adverse events were reported.