PTC Therapeutics is a global biopharmaceutical company focused on developing and commercializing medicines for rare genetic diseases, primarily in neurology and metabolism. PTC sells branded drugs at premium prices to small patient populations, with reimbursement coming from government health programs and private insurers. Products are distributed through specialty and hospital pharmacies, and PTC relies entirely on contract manufacturers. PTC's near-term growth is anchored by Sephience (sepiapterin), launched in mid-2025 for phenylketonuria (PKU), a rare inherited metabolic disorder. Sephience works through a dual mechanism targeting a broader patient population than existing BH4 therapies, including patients with classical PKU unresponsive to prior treatments. PTC targets roughly 17,000 U.S. patients and 58,000 globally, with a stated U.S. revenue opportunity exceeding $1B. PTC also markets two Duchenne muscular dystrophy (DMD) drugs: Translarna, approved outside the U.S. for a specific mutation subtype, and Emflaza, a corticosteroid approved in the U.S. — though both face headwinds from Translarna's EU authorization loss and generic competition for Emflaza. PTC previously earned royalties on Evrysdi, an oral spinal muscular atrophy treatment commercialized by Roche, but sold those royalty rights to Royalty Pharma in December 2025. PTC also out-licensed its Huntington's disease program (votoplam) to Novartis for up to $1.9B in milestones plus profit-sharing, retaining pipeline upside with no further development cost. PTC supplements its portfolio through acquisitions and licensing, having built its current commercial lineup via deals with Censa, Agilis, and BioElectron.