PTC’s Phase III Data Sets Up PKU Competition With BioMarin

Rare disease-focused PTC Therapeutics, Inc. unveiled Phase III data for its phenylketonuria (PKU) candidate sepiapterin (PTC923) on 17 May that looks capable of positioning the oral synthetic drug to compete with BioMarin Pharmaceutical Inc.’s two approved PKU therapies. But, while PTC highlighted data from a subset of more severe PKU patients, at least one analyst questioned whether the sample size would be large enough to win sepiapterin a broad label indication.

In a 98-patient readout from the Phase III APHENITY trial, PTC reported a mean 63% reduction in phenylalanine (Phe) at six weeks compared to minimal reductions among patients receiving placebo...