Merck Serono announces positive Phenoptin results

Merck Serono has this week announced positive results in its phase III clinical trial of Phenoptin (sapropterin dihydrochloride) used in combination with diet in patients aged four to 12.

Phenoptin is a novel orally administered small molecule being developed for the treatment of patients with phenylketonuria (PKU) who have shown increased levels of phenylalanine (Phe).

The drug, co-developed with BioMarin, showed a decrease in phenylalanine levels in the blood and an increased tolerance of phenylalanine, together with the compound being well tolerated in patients under dietary control.

Results from an earlier phase III clinical trial presented in March 2006 showed a significant reduction in Phe levels after six weeks in patients administered with Phenoptin, compared to those receiving a placebo.

Dr Harvey Levy, professor of paediatrics at Harvard Medical School, said: “This is the first time a controlled study has demonstrated the potential of tetrahydrobiopterin, or 6R-BH4, to liberalise diet in PKY patients.”

He added that if the drug becomes approved, it will offer an opportunity to patients to relax their diets and potentially abolish the need for nutritional supplementation.

Earlier this month, Merck KGaA announced that it was formally exploring the option of divesting its generics business following what it described as “far-reaching changes” taking place in the sector.