09/13/2007

PTC Therapeutics, Inc. Announces $20 Million Strategic Investment from Celgene Corporation

PTC Grants Celgene Option for Collaboration on Two Targets Utilizing GEMS Platform

SOUTH PLAINFIELD, NJ – September 13, 2007 - PTC Therapeutics, Inc. (PTC), a biopharmaceutical company focused on the discovery, development and commercialization of small-molecule drugs targeting post-transcriptional control mechanisms, today announced that that Celgene Corporation (NASDAQ: CELG) will make a $20 million equity investment in PTC. At the same time, PTC will grant Celgene an option for an exclusive research and option agreement on two oncology targets for the development of orally bioavailable small molecules through the application of PTC’s GEMS (Gene Expression Modulation by Small-molecules) technology.

Under the terms of the research and option agreement, if the Celgene option is exercised, PTC may receive funding for research efforts and earn substantial milestone payments per target for achieving certain discovery, development, regulatory, and commercial objectives. Celgene will receive exclusive worldwide rights and pay PTC royalties on worldwide net sales of any products resulting from this collaboration.

“Celgene is widely recognized for its scientific innovation and commercial success in developing novel oral solutions for areas of high unmet medical need. We are delighted to welcome them as an investor,” said Stuart Peltz, Ph.D., President and CEO of PTC Therapeutics. “We have developed an innovative approach to drug discovery in our GEMS technology and have demonstrated its potential through our multiple internal programs and collaborations. This significant support from Celgene will strengthen our continuing efforts to develop and commercialize products based on our GEMS technology.”

"We are pleased to make this investment in PTC Therapeutics, a demonstrated leader in the discovery and development of small molecules targeting RNA biology," said Sol Barer, Ph.D., Chairman and Chief Executive Officer of Celgene. "This investment, combined with the research option, enables Celgene to participate with PTC in the development of innovative therapies."

ABOUT GEMS

GEMS is PTC’s novel and proprietary technology platform for the identification of small-molecules that modulate post-transcriptional control mechanisms. Compounds identified through the GEMS technology target processes that act through the untranslated regions (UTRs) of messenger RNA (mRNA) molecules. PTC has successfully employed the GEMS technology in drug discovery programs in oncology, infectious diseases, cardiovascular diseases, and neuromuscular disorders.

ABOUT PTC THERAPEUTICS, INC.

PTC is a biopharmaceutical company focused on the discovery, development and commercialization of orally administered, proprietary, small-molecule drugs that target post-transcriptional control processes. Post-transcriptional control processes regulate the rate and timing of protein production and are of central importance to proper cellular function. PTC’s internally-discovered pipeline addresses multiple therapeutic areas, including genetic disorders, oncology and infectious diseases. In addition, PTC has developed proprietary technologies and extensive knowledge of post-transcriptional control processes that it applies in its drug discovery and development activities, including the Gene Expression Modulation by Small-molecules (GEMS) technology platform, which has been the basis for collaborations with leading pharmaceutical and biotechnology companies such as Pfizer, CV Therapeutics and Schering-Plough. For more information, visit the company’s website, www.ptcbio.com.

FOR MORE INFORMATION:

Contact:
Jane Baj
PTC Therapeutics, Inc.
(908) 222-7000, x167
jbaj@ptcbio.com
Sheryl Seapy
Pure Communications
(949) 608-0841
sheryl@purecommunicationsinc.com