November 2016

CHMP Recommends Renewal of Translarna's™ Marketing Authorization for Nonsense Mutation Duchenne Muscular Dystrophy Based on Continued Positive Benefit-Risk Assessment

--PTC to conduct a post-authorization clinical trial --

SOUTH PLAINFIELD, N.J., Nov. 11, 2016 /PRNewswire/ -- PTC Therapeutics, Inc. (NASDAQ: PTCT) today announced that the Committee for Medicinal Products for Human Use (CHMP) of the European Medicines Agency (EMA) has recommended the renewal of the conditional marketing authorization of Translarna™ (ataluren) for the treatment of nonsense mutation Duchenne muscular dystrophy (nmDMD) in ambulatory patients five years and older. In connection with the renewal, the marketing authorization will include a specific obligation to conduct an additional long-term post-authorization trial.

"We are pleased with this outcome which took into account all available data for Translarna," said Stuart W. Peltz, Ph.D., Chief Executive Officer, PTC Therapeutics, Inc. "This decision reflects the benefit that Translarna is having for patients suffering from nonsense mutation Duchenne muscular dystrophy."

The CHMP opinion forms the basis for a European Commission decision on the renewal of the marketing authorization. The European Commission generally delivers its decision within three months.

"Translarna has shown clinically meaningful benefits for patients," said Eugenio Mercuri, M.D., Professor of Pediatric Neurology at the Catholic University, Rome, Italy. "Duchenne is a devastating disease with a progressive loss of function. Maintaining function is of the utmost importance to patients."

"The consistency of Translarna's benefit shown across key endpoints is impressive for a dystrophin replacement therapy," said Craig McDonald, M.D., Professor of Pediatrics and Chair of the Department of Physical Medicine & Rehabilitation at University of California. "I am encouraged for the DMD community by the CHMP's recommendation."

The CHMP has requested that PTC conduct a new 18-month randomized, placebo-controlled study in patients with nonsense mutation Duchenne muscular dystrophy, as a specific post-authorization obligation, with results expected to be available in the first quarter of 2021. This study will be followed by an 18-month open-label extension period where all patients will be switched to Translarna. PTC has proposed a trial similar in size to ACT DMD and details of the protocol are expected to be finalized in future interactions with the EMA. Conditional marketing authorizations are subject to annual reassessment and renewal.

"For boys with Duchenne, every day matters and functional loss cannot be regained. Patients need access to innovative new therapies like Translarna," stated Filippo Buccella, founder of the Italian Parent Project, a patient advocacy group for Duchenne Muscular Dystrophy.

About Translarna™ (ataluren)
Translarna, discovered and developed by PTC Therapeutics, Inc., is a protein restoration therapy designed to enable the formation of a functioning protein in patients with genetic disorders caused by a nonsense mutation. A nonsense mutation is an alteration in the genetic code that prematurely halts the synthesis of an essential protein. The resulting disorder is determined by which protein cannot be expressed in its entirety and is no longer functional, such as dystrophin in Duchenne muscular dystrophy. Translarna is licensed in the European Economic Area for the treatment of nonsense mutation Duchenne muscular dystrophy in ambulatory patients aged five years and older. Translarna is an investigational new drug in the United States . The development of Translarna has been supported by grants from Cystic Fibrosis Foundation Therapeutics Inc. (the nonprofit affiliate of the Cystic Fibrosis Foundation); Muscular Dystrophy Association; FDA's Office of Orphan Products Development; National Center for Research Resources; National Heart, Lung, and Blood Institute; and Parent Project Muscular Dystrophy.

About Duchenne Muscular Dystrophy 
Primarily affecting males, Duchenne muscular dystrophy (DMD) is a progressive muscle disorder caused by the lack of functional dystrophin protein. Dystrophin is critical to the structural stability of skeletal, diaphragm, and heart muscles. Patients with DMD, the more severe form of the disorder, lose the ability to walk as early as age 10 and experience life-threatening lung and heart complications in their late teens and twenties. It is estimated that a nonsense mutation is the cause of DMD in approximately 13 percent of patients.

About PTC Therapeutics 
PTC is a global biopharmaceutical company focused on the discovery, development and commercialization of orally administered, proprietary small molecule drugs targeting an area of RNA biology we refer to as post-transcriptional control. Post-transcriptional control processes are the regulatory events that occur in cells during and after a messenger RNA, or mRNA, molecule is copied from DNA through the transcription process. PTC's internally discovered pipeline addresses multiple therapeutic areas, including rare disorders and oncology. PTC has discovered all of its compounds currently under development using its proprietary technologies. PTC plans to continue to develop these compounds both on its own and through selective collaboration arrangements with leading pharmaceutical and biotechnology companies. For more information on the company, please visit our website www.ptcbio.com.