PNP Therapeutics

About PNP Therapeutics

William B. Parker, Ph.D.

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William B. Parker, Ph.D.

Dr. Parker obtained a Ph.D. in Pharmacology in 1984 from George Washington University and received further post-doctoral research training at the University of North Carolina at Chapel Hill (1984 to 1988). During his research career at Southern Research Institute (1988 to 2015) he studied the mechanism of action of purine and pyrimidine antimetabolites, which are an important class of drugs used in the treatment of cancers and viral infections. His research was supported by twelve grants from the National Institutes of Health. He is currently working with PNP Therapeutics Inc. to advance a novel therapy for the treatment of solid tumors. He is an adjunct professor in the Department of Pharmacology at the University of Alabama Birmingham (UAB) and the Comprehensive Cancer Center at UAB.

Because of his research, Dr. Parker has gained world-wide recognition as an expert on the development of nucleoside analogs for the treatment of cancer and viral infections. He has published more than 100 peer reviewed manuscripts that describe his research including a comprehensive review describing the enzymology and mechanism of action of all purine and pyrimidine antimetabolites that are currently used to treat cancer. He was chair of the Nucleosides, Nucleotides, & Oligonucleotides Gordon Conference in 2013, an international meeting that is devoted to drug discovery involving these molecules. He has served on numerous peer review panels for various journals and the National Institutes of Health to review manuscripts and grant applications that involve research into the development of new anticancer and antiviral drugs.

From 1988 to 2015, he was part of a drug discovery team at Southern Research Institute that has designed, synthesized, and evaluated numerous nucleoside analogs for the treatment of cancer. This team was successful in the discovery of a clofarabine, which was approved in 2004 for the treatment of childhood acute lymphocytic leukemia, and thiarabine, which has been evaluated in 3 clinical trials for the treatment of solid tumors and hematological malignancies. He (with Dr. Thottassery) was responsible for discovery of a novel DNA methyltransferase 1 (DNMT1) inhibitor. A phase I clinical trial (sponsored by the NExT program of the National Cancer Institute) began in the second quarter of 2015 to initiate clinical evaluation of this compound. The research conducted in Dr. Parker's laboratory is responsible for much of the information known about the mechanism of action of these compounds. His work has greatly aided our understanding of how these agents kill cancer cells, has determined how they differ from other compounds of similar structure, and has significantly contributed to their selection as clinical candidates.

Dr. Parker is co-inventor of a gene therapy strategy to treat human solid tumors, which involves the use of E. coli purine nucleoside phosphorylase (PNP) to activate fludarabine phosphate, and is a founder of PNP Therapeutics Inc. He was the principal investigator of a National Cooperative Drug Discovery Grant (NCDDG) from the National Cancer Institute (1995 to 2005) where he led molecular biologists, biochemists, chemists, X-ray crystallographers, and cancer chemotherapists in the development of this strategy. A phase I clinical trial (sponsored by PNP Therapeutics) that evaluated safety and efficacy of this strategy in head and neck cancer patients has recently been completed. The therapy was very well tolerated and significant responses were observed in many of the treated tumors in cohorts 3 and 4, including 2 complete responses. These results indicate that there is significant clinical promise to this anticancer approach.