Pharma

Head and neck cancer treatment combines enzyme, existing drugs to make tumors self-destruct

A clinical-stage biopharmaceutical company is testing a new targeted cancer treatment based on the notion that solid tumors can be compelled to develop their own chemotherapy and self-destruct. In PNP Therapeutics Inc.’s platform technology, an E. coli purine nucleoside phosphorylase (PNP) gene injected directly into a tumor produces enzymes that interact with a circulating prodrug, […]

A clinical-stage biopharmaceutical company is testing a new targeted cancer treatment based on the notion that solid tumors can be compelled to develop their own chemotherapy and self-destruct.

In PNP Therapeutics Inc.’s platform technology, an E. coli purine nucleoside phosphorylase (PNP) gene injected directly into a tumor produces enzymes that interact with a circulating prodrug, which becomes an active chemotherapeutic agent upon diffusion into the tumor cells.

PNP’s first product uses fludarabine phosphate, a U.S. Food and Drug Administration-approved chemotherapeutic agent already in clinical use for lymphocytic leukemia. In preclinical tests, the therapy killed both dividing and nondividing cells, the company says on its website, whereas many conventional antitumor agents target mainly the proliferation of the tumor. It also has demonstrated that only a small percentage of tumor cells needed to be transfected to significantly reduce tumor volume.

According to a recent U.S. Securities and Exchange Commission filing, PNP has nearly completed a $750,000 financing round. CEO Frank Hunt did not respond to an email regarding the company’s next milestone, but it got FDA approval of its IND application and began a clinical trial last year.

The treatment will at first target head and neck cancers, like oral and pharyngeal cancers, but the company says its approach has also worked on animal models with other cancers including ovarian, lymphoma, colon, brain, liver, prostate and pancreatic.

The National Cancer Institute estimates that approximately $3.1 billion is spent annually on treatment of head and neck cancers, although (PDF) incidence and mortality have been declining over the past two decades. Last year, the FDA approved another drug for these cancers, Erbitux (Merck, Eli Lilly & Co., Bristol-Myers Squibb Co. and ImClone), that is also used with a chemotherapeutic agent. Navidea Biopharma, formerly known as Neoprobe, is investigating the use of its targeting agent Lymphoseek in head and neck cancer patients, and IRX Therapeutics has also tested its lead drug in head and neck cancer patients in a phase 2a trial.

Based in Birmingham, Alabama, PNP uses technology from the University of Alabama at Birmingham Research Foundation and Southern Research Institute of Birmingham. Investors include the Birmingham Technology Fund, Phase 1 Holdings and Vulcan Medical Ventures.