PTC Therapeutics Inc. has announced an agreement to monetize a portion of the risdiplam royalty stream for $650 million from Royalty Pharma plc. The capital from the collaboration will enable PTC to further develop and expand its rare disorder portfolio, particularly its validated splicing, Bio-e and gene therapy platforms.   Risdiplam is an investigational survival motor neuron 2 (SMN2) splicing modifier for SMA and is an orally administered liquid. It is designed to increase and sustain SMN pr...