ProNAi Announces DNA Interference (DNAi(R)) Drug Development Strategy for 2007.

Pioneer in Nucleic Acid-Based Drug Development Aims to Bring PNT2258 Therapeutic Candidate to IND Submission by Mid-Year - Company to Formally Announce Preclinical Data in the Spring

KALAMAZOO, Mich. -- ProNAi Therapeutics, Inc., a biopharmaceutical company pioneering a new class of nucleic-acid drugs based on DNA interference (DNAi[R]), today announced its drug development strategy for 2007, and its plans to bring its lead therapeutic candidate, PNT2258, to IND submission by mid-year.

DNAi[R] is a novel approach to targeting genomic DNA using sequence-specific therapeutic agents, employing single strands of DNA to target and treat genes responsible for complex genetic diseases, such as cancer.

By acting at the DNA level, where only one or two copies of the gene exist per cell, treatment can be targeted more efficiently by DNAi[R] drugs. With fewer targets, the activity of a DNAi[R] drug is expected to last longer at lower doses, and reduce some of the toxicity issues prevalent with other marketed therapies. Additionally, DNA-related therapies are potentially more cost effective to produce.

In a promising advance for DNA-based drugs, ProNAi has overcome a long-standing barrier to effective DNA therapy delivery - by means of a viable method for the safe, effective delivery of therapeutic oligonucleotides - the keystone to making DNAi[R] a viable treatment option in humans.

Dr. Richard D. Gill, President and CEO of ProNAi, said, "For many, many years, the promise of DNA-related therapies has gone largely unfulfilled, due to a daunting number of obstacles - lack of specificity and potency, high manufacturing costs, as well as the inability to deliver effective doses of DNA-based drugs - a problem that also still affects RNAi-based approaches currently in vogue. ProNAi has worked steadily and methodically to overcome each of these barriers to nucleic acid-based therapeutics and we fully expect to have our lead drug candidate, PNT2258, ready for IND submission by mid-year."

Robert Forgey, Co-Founder and Chief Operating Officer of ProNAi, said, "DNAi[R] is radically different from competing approaches such as antisense, decoy, RNAi, shRNA, triplex, immunostimulators, and other nucleic acid drug approaches, and displays significant potential advantages over each. For example, current RNAi and antisense treatment approaches concentrate on binding to messenger RNA (mRNA) to slow or stop disease progression. However, because mRNA molecules are continually synthesized from a disease gene, the need for destruction of the molecule must be continuous for it to remain effective. This means RNAi drugs need high doses, which in turn means higher toxicity as well as cost - even if they solve their delivery problem. DNAi[R] eliminates this issue entirely, by focusing on the gene itself, channeling therapies one level up where 'less is more' in terms of drug dose and effectiveness."

Dr. Gill added, "ProNAi is looking forward to demonstrating the viability of DNAi[R]-based drugs in the coming year, as we announce our very promising preclinical results for PNT2258, which has shown exciting in vivo efficacy in xenograft mice for a number of cancers. Our first drug formulations show promising utility against multiple target genes, and we are targeting well-documented, non-translated genomic sequences. We are also examining the potential for a Dx/Rx combination, and will further develop that possibility."

About ProNAi Therapeutics, Inc.

ProNAi Therapeutics, Inc. is a biopharmaceutical drug development company pioneering a new class of nucleic-acid drugs based on DNA interference (DNAi[R]), which employs single strands of DNA to target and treat non-transcribed regions of genomes responsible for complex genetic diseases. ProNAi is currently developing multiple DNAi-based drug candidates with the potential to treat multiple cancers, including non-Hodgkin's lymphoma, prostate, breast, and colon cancers. The company's lead drug candidate, PNT-2258, which has demonstrated in vivo efficacy in a variety of human tumor xenograft models, is currently in preclinical development. ProNAi is also exploring the potential of DNAi-based therapies for indications such as diabetes, Alzheimer's and inflammatory disease.

ProNAi is based in Kalamazoo, Michigan. For more information, please visit: www.pronai.com.