Merck PKU Drug Trial Meets Primary Endpoint

Merck Serono announced that its Phase IIIB SPARK (Safety Pediatric EfficAcy PhaRmacokinetic with Kuvan) study evaluating Kuvan in children less than 4 years old who have phenylketonuria (PKU) has met its primary endpoint.

Results of the first 26 weeks of SPARK showed that the addition of Kuvan (sapropterin dihydrochloride) to a phenylalanine-restricted diet in children less than 4 years old who have phenylketonuria (PKU) and have been previously responsive to Kuvan significantly increased tolerance to phenylalanine compared with a phenylalanine-restricted diet alone. Safety profile of Kuvan was reported to be consistent with the drug’s profile described in the European Summary of Product Characteristics.

John Orloff, global head of clinical development at Merck's biopharmaceutical division Merck Serono, said, “PKU is a serious rare disease that has a significant impact on patients and their families. We are delighted by the positive outcome of this study, and remain dedicated to further improving our understanding of PKU in infants and young children.”

Phenylketonuria (PKU) is an inborn metabolic disorder that leads to the toxic accumulation of phenylalanine in the brain and blood. If left untreated, PKU can result in intellectual disability, seizures, and other serious medical problems.

Kuvan is the first and currently the only medication in combination with dietary modifications in Europe designed to reduce the concentration of phenylalanine in the blood and in the brain. The drug is indicated for patients with tetrahydrobiopterin (BH4) deficiency, and in those aged 4 years and older with PKU (due phenylalanine hydroxylase enzyme deficiency) who are responsive to Kuvan. There is currently no approved medication in the EU for the treatment of PKU in patients four years old and younger.

Ania Muntau, Klinikum University Munich, Germany, and lead investigator for SPARK, said, “This is the first time a controlled study such as this has been conducted in children below 4 years of age with PKU. These study findings with Kuvan in addition to phenylalanine-restricted diet could lead to a new disease management approach to control blood phenylalanine levels right from birth.”

The results of the first 26 weeks of the SPARK study will be presented at upcoming international scientific meetings and published in a peer-reviewed journal. The company said positive outcome of the study will form the basis of a regulatory submission for a label extension later in 2015.