The Role of the Platinum Derivatives in Cancer Therapy

The discovery of cisplatinum and the subsequent development of its derivatives (carboplatin and oxaliplatin) represent an interesting saga in modern oncology. When Rosenberg observed in 1960s that platinum electrodes in salt water baths inhibited the growth of bacteria and fungi it lead to the isolation of cis-dichloro diamine platinum (cisplatin). Its application in testicular cancer provided a dramatic leap forward for this heretofore-lethal disease. Subsequent applications in ovary and lung cancers lead to some of the most effective therapies in modern oncology. Although the exact mechanisms of action continue to be investigated, the platination of guanine residues in DNA constitutes the principle mechanism of cytotoxicity.

The use of the human tumor laboratory model has provided us the luxury of exploring the platinum drugs in a wide variety of diseases. Among our published discoveries has been the relative equivalence of the platinum derivatives, as well as their profound synergy with agents like gemcitabine. It is of significant interest that this broadly effective class of compounds — extensively applied in the treatment of lung, colorectal, ovarian and breast cancers, as well as others — remains less active in the hematologic neoplasms. This is in striking counter distinction to nearly all other classes of chemotherapeutics.

Among our most gratifying observations, from the early 1990s, was the clear and profound activity of the platinum derivatives in breast cancers. We feel that our discoveries, outlined in an editorial published in 2000 (The Once and Future Role of Platinum Agents in Advanced Breast Cancer), in no small part have influenced the broad application of platinum in modern breast cancer management.

It was not genius or divine intervention that lead us to these important discoveries, but, quite simply, the use of a validated human tumor model that accurately probed tumor types, leading us to these findings. It is virtually impossible for an unbiased observer to review these contributions and not recognize that the human tumor model has been the conduit by which these discoveries were made.

The proper study of human cancer is human cancer. Our results speak for themselves when it comes to ovarian, breast and hematologic neoplasms, treatments for which can be traced directly to our laboratories.

About Dr. Robert A. Nagourney
Dr. Nagourney received his undergraduate degree in chemistry from Boston University and his doctor of medicine at McGill University in Montreal, where he was a University Scholar. After a residency in internal medicine at the University of California, Irvine, he went on to complete fellowship training in medical oncology at Georgetown University, as well as in hematology at the Scripps Institute in La Jolla. During his fellowship at Georgetown University, Dr. Nagourney confronted aggressive malignancies for which the standard therapies remained mostly ineffective. No matter what he did, all of his patients died. While he found this “standard of care” to be unacceptable, it inspired him to return to the laboratory where he eventually developed “personalized cancer therapy.” In 1986, Dr. Nagourney, along with colleague Larry Weisenthal, MD, PhD, received a Phase I grant from a federally funded program and launched Oncotech, Inc. They began conducting experiments to prove that human tumors resistant to chemotherapeutics could be re-sensitized by pre-incubation with calcium channel blockers, glutathione depletors and protein kinase C inhibitors. The original research was a success. Oncotech grew with financial backing from investors who ultimately changed the direction of the company’s research. The changes proved untenable to Dr. Nagourney and in 1991, he left the company he co-founded. He then returned to the laboratory, and developed the Ex-vivo Analysis - Programmed Cell Death ® (EVA-PCD) test to identify the treatments that would induce programmed cell death, or “apoptosis.” He soon took a position as Director of Experimental Therapeutics at the Cancer Institute of Long Beach Memorial Medical Center. His primary research project during this time was chronic lymphocytic leukemia. He remained in this position until the basic research program funding was cut, at which time he founded Rational Therapeutics in 1995. It is here where the EVA-PCD test is used to identity the drug, combinations of drugs or targeted therapies that will kill a patient's tumor - thus providing patients with truly personalized cancer treatment plans. With the desire to change how cancer care is delivered, he became Medical Director of the Todd Cancer Institute at Long Beach Memorial in 2003. In 2008, he returned to Rational Therapeutics full time to rededicate his time and expertise to expand the research opportunities available through the laboratory. He is a frequently invited lecturer for numerous professional organizations and universities, and has served as a reviewer and on the editorial boards of several journals including Clinical Cancer Research, British Journal of Cancer, Gynecologic Oncology, Cancer Research and the Journal of Medicinal Food.

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