As a young medical student in 1974, Rigdon Lentz was intrigued by the fact some people developed progressive cancers while others did not. In the 1970’s research had shown that most if not all cancers were immunogenic (possessed altered self antigens or tumor associated antigens (TSAs) on their cell membranes and possessed killer cells in their blood and in their tumors). The question to Lentz was, why did the immune system ever tolerate cancer?
Although the prevailing theory of genetic mutation attempted to explain how cancer cells were created, but it did not explain why the body would tolerate the mutated immunogenic cells, and allow them to grow and eventually cause the death of their host.
These questions led Dr. Lentz to the study of immunology. From his initial curiosity has followed a lifetime of research and clinical exploration of the mystery of why cancer, alone among human diseases, seems to be invisible to the body's immune system. In essence, how can an intact immune system tolerate a cancer?
In his quest to answer this basic question, Dr. Lentz has accumulated extensive experience as a research scientist. He has held positions in academia, authored numerous major scientific papers, and served as the principal investigator or co-investigator in numerous clinical trials. Dr. Lentz has been for many years a senior fellow at the Department of Immunology and a senior scientist at the International Center for Interdisciplinary Studies of Immunology at Georgetown University. He is a contributing author for the newest edition of the standard medical school text on immunology to be published in 2011, and co-author of the textbook Therapeutic Plasma Exchange and Selective Plasma Separation Methods.
Dr. Lentz has been equally committed to patient care, serving as the head of oncology in both clinical and hospital settings, chief of several tumor boards supervising therapeutic care, director of a chemotherapy infusion center, and founder of a major oncology clinic. He has personally treated or supervised the care of many thousands of cancer patients.
Throughout his career Dr. Lentz has sought to turn his discoveries about cancer and the immune system into beneficial therapeutic reality. In 1982 Dr. Lentz was the first to posit formally that cancer cells produce a then-unknown molecule that acts as a decoy for the immune system, rather like warplanes spray "chaff" to confuse defensive fire. He was the first to prove the existence of these inhibitors, using a series of animal experiments to show that simply removing molecules from the blood in a certain range of molecular weight elicited an immune response against malignant tumors – perhaps the first clinical provocation of a tumor-specific “cytokine storm”.
In the research for which he is best known, Dr. Lentz was later able to identify the exact molecules which inhibited the immune response, and proved conclusively they were produced by the cancer cells themselves. Many other researchers have since corroborated the key role of these inhibitors, called soluble Tumor Necrosis Factor receptor 1 and 2 (TNFr1 and TNFr2). So far every cancer investigated has proven to use this same mechanism to shield itself from the immune system. This is a discovery with profound implications for cancer research and treatment.
This research also led to the development of the drug Enbrel by Immunex. This drug is composed of two TNFr2 receptors fused together. This drug and its follow-on antibody-based drugs have revolutionized the treatment of rheumatoid arthritis and other autoimmune diseases by blocking TNF. We now know that we can cause an inflammatory attack by removing these inhibitors, or block inflammatory-mediated tissue destruction by giving these inhibitors. This knowledge proceeds from the work of Dr. Lentz.
For a number of physiological reasons Dr. Lentz thought it was better to physically remove these inhibitors from the blood of a cancer patient then to insert a drug and interfere with them. The early machines developed by Dr. Lentz for therapeutic use proved the theory in humans. The original centrifuges were replaced by blood and plasma filters and evolved over the years with ever-increasing efficiency. A breakthrough occurred in the late 1990’s when Lentz made the first adsorption columns. Dr. Lentz realized that if he could create an adsorption column for TNFr1 and TNFr2, he could build a simpler and more efficient system that would remove only the inhibitors - and nothing else - and so allow intensive therapy over a period of days, weeks or months if necessary, with minimal significant side effects. This would lead the way to make treatment available to many more patients than the earlier extracorporeal devices that used ultrafiltration and plasma fractionation.
Over a period of years, Dr. Lentz developed the antigens and antibodies needed to bind the inhibitors to the adsorption column, first solving the problem of producing them on a small scale and then passing the information off to other groups to mass produce them. He moved to Germany – along with Japan, a world center for dialysis and blood-filtration technology – and developed a machine around his adsorption column, including the related software, and was successful in human trials of the new technology, demonstrating both efficacy and safety. After decades of work, it seemed that large scale availability of his therapy was about to become a reality.
At this point Dr. Lentz assigned his patents – over 60 patents worldwide – to a small venture capital-backed biotech manufacturing firm, BioPheresis, to produce the first commercial version of his technology. Dr. Lentz remained focused on patient care and research. While the company has managed to acquire a CE certification from the EU, signifying its acceptance as a medical device and treatment modality, the process of commercialization remains ongoing.
About Praxis Lentz
In 2002 Dr. Lentz met and later married Kiran Lentz MD, a noted German physician in her own right. Together they decided to establish a clinic devoted to a holistic immunologic treatment of cancer patients combined with Immunepheresis. They purchased a beautiful clinic in Prien am Chiemsee, the famous lake resort of Bavaria, and have now established the only center in the world capable of offering comprehensive immunologic cancer care and Immunepheresis to cancer patients. Here the Doctors Lentz and colleagues treat patients from all over the world with cancers of all types, from early stage to inoperable.