May 12 2010

Approval of Therapeutic Cancer Vaccines

Last month, Dendreon was granted approval for Provenge®, the first cell based cancer vaccine for treatment of asymptomatic or minimally symptomatic metastatic castrate resistant (hormone refractory) prostate cancer.  Provenge is the first cancer treatment that utilizes the strength of the patient’s own immune system to fight tumors.  This approval could mark the beginning of a new era in cancer therapeutics and hopefully indicates the first in a series of similar treatments for other cancers.

This new generation of targeted therapeutics for the treatment of cancer is emerging from the growing knowledge base of biomedical drug discovery.  Based on a biological approach, novel cancer therapeutics currently under development include agents in the areas of vascular targeting, antisense, gene transfer, immunotherapies, and apoptotic induction.  These innovative treatments hold the promise of improved therapeutic choices for selected cancer patient populations and have the benefit of diminished side effects compared with traditional cytotoxic therapies.  A review of these programs indicate there is no optimal solution for determining clinical benefit for therapeutic cancer vaccines by targeting therapies to approach patient subpopulations under current drug development paradigms.  Greater consideration and appreciation of the positive risk-benefit ratio, consideration of alternative and more appropriate clinical trial designs, and expansion of prospective definitions of subpopulations would clearly facilitate further development of these promising therapies.  A detailed article on therapeutic cancer vaccines and the need for innovative approaches written by Jennifer R. Weidman PhD, R.A.C can be found in the July 2009 edition of Journal for Clinical Studies (PDF link).

Currently, Cancer Advances, a wholly owned subsidiary of Cato BioVentures, is developing the company’s lead compound, a cancer vaccine named Polyclonal Antibody Stimulator (PAS), for the treatment of gastrointestinal cancers.  Few products are currently in late-stage clinical development for the treatment of gastric and pancreatic cancer.  Because there remains a significant unmet medical need, a wide variety of immunomodulators are being developed including cytokines, adaptive T-cells, therapeutic vaccines, and monoclonal antibodies; PAS falls under the broad category of therapeutics known as immunomodulators.  PAS functions by stimulating the immune system in the recipient to produce endogenous polyclonal antibodies to gastrin without the risks and limitations associated with serum-derived polyclonal treatment or monoclonal antibody therapy.

This is a post by Laura DiMichele, Ph.D., R.A.C. Laura is a Clinical Strategy Scientist at Cato Research.