Germany’s Merck KGaA has submitted an application with European regulators to get marketing approval for sapropterin as an oral treatment for hyperphenylalaninemia (HPA).

The firm’s Merck Serono unit has filed sapropterin, formerly known as Phenoptin, with the European Medicines Agency for patients with phenylketonuria or tetrahydrobiopterin deficiency which causes HPA. The latter is a disorder characterised by increased amounts of the amino acid phenylalanine in the bloodstream which is toxic to nerve cells and, if left untreated, can result in brain damage.

There are at least 50,000 people diagnosed with hyperphenylalaninemia due to PKU or BH4 deficiency in the developed world and the only alternative for PKU patients to manage their disease is a diet highly restricted in phenylalanine. The filing is based on data from two international, Phase III trials which show that treatment with sapropterin reduces blood phenylalanine levels and may reduce the need to limit phenylalanine in patients’ diet. The most frequently reported undesirable effects included headache, runny nose, diarrhoea, vomiting and abdominal pain, but these adverse events were generally mild to moderate and transient, Merck noted.

The filing of sapropterin, which had previously received orphan status for the treatment of HPA from both the EMEA and the US Food and Drug Administration, is an important milestone for patients with phenylketonuria or BH4 deficiency, said Roberto Gradnik, head of Merck Serono’s operations for Europe. “These are serious, debilitating diseases for which there is currently no
drug approved in Europe,” he noted.
Sapropterin is being developed in partnership with the USA’s BioMarin Pharmaceutical which has rights to market the product on its home turf, while Merck Serono has exclusive rights to the drug elsewhere in the world, except Japan.

Easypod approved by FDA
Merck also noted that its US affiliate, EMD Serono, has received FDA approval for Easypod, an innovative delivery system for the administration of Saizen [somatropin (rDNA origin) for injection], a treatment for growth hormone deficiency. The firm claimed that the device is the first of its kind and was designed in conjunction with patients and healthcare professionals “for ease of daily use, reliability and convenience”.  
“In today’s high-technology world, it is necessary to continue to innovate by developing delivery systems with easy-to-use settings and real-time data,” said Fereydoun Firouz, EMD Serono’s chief executive. The product is already available in Europe, the major countries of Latin America and Australia.