Pharmaceutical Business review

Merck Serono genetic disorder drug shows promise

Phenoptin is being developed in partnership with BioMarin, for the treatment of patients with phenylketonuria (PKU), a rare genetic disorder where sufferers have a deficiency of an enzyme needed to metabolize the amino acid phenylalanine.

The results show that all efficacy and safety endpoints of the study were met. In addition, the data showed that Phenoptin was well tolerated in younger PKU patients who were under dietary control.

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

The results showed Phenoptin treatment caused a significant increase in phenylalanine tolerance as well as a reduction in blood phenylalanine levels. At the end of the study, patients on Phenoptin were able to increase their daily Phe supplement by a mean of 20.9mg/kg versus a mean of 2.9mg/kg for placebo patients.

BioMarin and Merck Serono remain on track to file the new drug application in the US and marketing authorization application in Europe for Phenoptin in the second and third quarters of 2007, respectively.