Presidio Pharmaceuticals Licenses Nuclear Exclusion Compounds from Cytokine PharmaSciences.

SAN FRANCISCO & KING OF PRUSSIA, Pa. -- Presidio Pharmaceuticals, Inc. and Cytokine PharmaSciences, Inc. announced today that Presidio has licensed from Cytokine PharmaSciences the rights to a series of preclinical-stage compounds for treatment of HIV-1 infection. The agreement also includes the Nuclear Exclusion Technology (NEXT[TM]), which allows treatment of HIV-1 infection and other viruses via inhibition of nuclear importation. Details of the agreement were not disclosed.

"We are enthusiastic about the Nuclear Exclusion Technology (NEXT[TM]), both for the potential of the current compounds that specifically target HIV-1 and for the broader application of the technology as a strategy for treating chronic viral infections," said Omar Haffar, Ph.D., President and CEO of Presidio.

Denny Willson, President and CEO of Cytokine PharmaSciences, stated: "Presidio has the scientific horsepower to take the NEXT[TM] compounds quickly from benchtop to the clinic. Their team combines broad experience in developing anti-viral therapies with the focus and pace of a start-up company. We are confident that they will succeed with our technology."

About Nuclear Exclusion Technology (NEXT[TM])

Nuclear exclusion is the process by which small molecule inhibitors prevent the translocation of viral genetic material from the cytoplasm of an infected cell to the cell's nucleus, where integration and replication occur. Nuclear translocation is an established cell trafficking pathway used to transport critical proteins, such as transcription factors and cell cycle regulators, into the nucleus. This process is mediated by two intracellular proteins, called karyopherins [eth] & [eth], that shuttle between the cytoplasm and the nucleus. Many viruses, including HIV-1 and HBV, utilize this established cell trafficking pathway to ensure efficient replication. In most cases, karyopherin [eth] recognises a specific amino acid sequence, called the Nuclear Localization Sequence, located on a viral protein associated with the ribonucleoprotein complex. This association of karyopherin [eth] and the specific viral protein is the pivotal step in nuclear translocation and is the molecular target for NEXT[TM]. Importantly, the present compounds and all future compounds will target the viral component of the protein-protein interaction and not karyopherin [eth]. This approach maximizes specificity of the inhibitory compounds and reduces potential toxicity.

About Presidio Pharmaceuticals, Inc.

Presidio Pharmaceuticals, Inc., is a specialty pharmaceutical company focused on developing and marketing novel therapeutics for chronic virus infections, including HIV-1, CMV, and HCV. Presidio Pharmaceuticals was founded in April 2006 with an initial investment from Sagamore Bioventures, a life-sciences venture fund with headquarters in San Francisco, California, and from George Rathmann. www.presidiopharma.com

About Cytokine PharmaSciences, Inc.

Cytokine PharmaSciences is a biopharmaceutical company located in King of Prussia (near Philadelphia), Pennsylvania. The company licenses technologies from academia and other sources, develops products from those technologies and outlicenses the products to third parties for marketing. www.cytokinepharmasciences.com