Royalty monetization is a financing tactic that is becoming increasingly popular during challenging times, and PTC Therapeutics Inc. is the latest firm to leverage a marketed drug to pay off debt and fuel its development pipeline. The South Plainfield, N.J.-based company agreed to sell up to $1.5 billion of its Evrysdi (risdiplam) royalty stream to Royalty Pharma plc, of New York. Evrysdi is a survival motor neuron 2 RNA splicing modifier approved by the U.S. FDA in 2020 to treat spinal muscular atrophy.