Cancer Doctor Invents Test For New Drugs That Cut Off Tumor's Blood Supply

Armen Hareyan's picture

In the August 11 online edition of the Journal of Internal Medicine reports discovery of the first practical laboratory test to guide the use of new-generation drugs that kill cancer cells by cutting off their blood supply. The new test, called the Microvessel Vascular (MVV) assay, was developed by Larry Weisenthal, MD, PhD., a medical oncologist who operates a cancer testing laboratory in Huntington Beach, California. The test works by measuring drug effects upon endothelial cells which make up blood vessels. Its use could prolong lives, save money, and spare patients exposure to harmful side-effects of ineffective chemotherapy treatments. The MVV test also could streamline development of new anti-cancer cancer drugs and identify effective and sometimes unexpected new drug combinations, such as one reported in the article. Used today principally by cancer physicians, to choose effective therapies on a patient-by-patient basis, the MVV assay also has potential for use as an early-warning screen for a variety of illnesses ranging from heart disease, cancer, diabetes, autoimmune disorders, and many others. Patents have been filed.

Dr. Weisenthal invented his new test after making the discovery that endothelial cells are present in cancer biopsy specimens even after the specimens are reduced to clusters of living cancer cells in order to make them suitable for testing in the laboratory. Endothelial cells form capillaries which carry oxygen and nutrients to cancer cells. Dr. Weisenthal noted that the effects of various drugs upon endothelial cells can be measured separately from the effects of those same drugs upon cancer cells within the same biopsy specimen. Dr. Weisenthal describes this as “anti-vascular effect versus anti-tumor effect.” Using this discriminatory property of his new test, Dr. Weisenthal has published several, original and often unexpected observations about the ways in which various drugs work.

Dr. Weisenthal further describes a logical extension of the MVV test, in which the ability to identify and characterize endothelial cells in mixed-cell populations could lead to early diagnosis and thereby more successful treatment of a broad spectrum of illnesses for which elevated numbers of circulating endothelial cells can be a feature. Potentially included are cancer, heart disease, diabetes, macular degeneration and others. Dr. Weisenthal envisions an accurate and inexpensive test, performed annually and based upon a simple blood draw, which would warn of the possible presence of a medical condition for which additional tests were warranted. The result would be earlier diagnosis of disease and also avoidance of much of the expensive and often unnecessary medical testing which occurs today.

The most immediate application of the MVV assay focuses upon cancer and specifically upon a much-heralded new class of agents called angiogenesis-inhibiting drugs, which work by attacking tumor vasculature and thereby starving cancer cells. A recent NIH listing contained over 800 active clinical trials involving angiogenesis-inhibiting agents. One such drug, called Avastin® (Genentech, South San Francisco, CA) had sales topping $2.2 billion in the U.S. alone in 2007. Many more angiogenesis-inhibiting drugs are in development.

One problem with these drugs, in addition to their high cost, is determining in advance who will benefit from them. The other problem is learning how to make the drugs more effective by using them in combination. The new MVV test could help on both fronts.


Dr Weisenthal expresses his belief that cancer can become a chronic and controllable illness through the use of combinations of anti-angiogenesis drugs. He says, “The long-awaited magic-bullet cure for cancer hasn’t materialized. Now we’re thinking more in terms of long-term control such as is the case with high blood pressure or diabetes. The way to make that happen sooner is to use our current ammunition more affectively.”

Dr. Weisenthal’s observations are reinforced by early studies of angiogenesis-inhibiting drugs in animal tumor models. In these studies, single agents produced only sporadic and temporary benefits. However, the effectiveness of these drugs increased substantially when they were administered in combination with other angiogenesis-inhibiting drugs. According to Dr. Weisenthal, the MVV test is the first practical tool that allows for design and testing of new anti-angiogenic drug combinations in human cancer.

Using his new MVV test, Dr. Weisenthal says that he often finds strong synergies among new combinations of different types of angiogenesis-inhibiting drugs, including drugs which were not previously known to have anti-angiogenic properties. One observation, which he reports in the Journal of Internal Medicine article, is that dimethylsulfoxide and ethanol are two compounds which often enhance the activity of anti-angiogenesis drugs in the laboratory. According to Dr. Weisenthal, therapeutic levels of ethanol in the bloodstream theoretically could be achieved simply by drinking wine or another alcoholic beverages in prescribed doses concurrent with receiving angiogenesis-inhibiting drugs. The concept might please some patients and alarm others but Dr. Weisenthal finds support in actual case studies reported in the medical literature. However, he warns that further clinical studies are required.

The MVV test is applicable to cancer patients whose bodies harbor cancer cells which are obtainable though biopsy. Currently, the test is available only through Dr. Weisenthal’s laboratory, the Weisenthal Cancer Group. Dr. Weisenthal says that he provides his testing services more like a medical practice and less like a typical reference laboratory. Although he regularly performs testing for cancer patients in the U.S. and also from several foreign countries, he intends to to stick to medicine and leave marketing of the MVV test to others. Dr. Weisenthal says that he would like to see the test become available to patients worldwide through service agreements with larger laboratory companies or with a biotechnology company which might develop a testing kit for sale to hospitals and laboratories. He also would like to license the test to pharmaceutical companies for use in new drug development.

Weisenthal Cancer Group is a privately-held commercial cancer testing laboratory and research facility headquartered in Huntington Beach, California. The company was founded in 1992 by Larry Weisenthal, MD, PhD, a medical oncologist and Associate Clinical Professor of Medicine at the University of California Irvine. Dr. Weisenthal trained at the NCI and has served in a variety of advisory and review capacities. Dr. Weisenthal is widely published and has been a keynote speaker at numerous meetings and symposia presented by oncology societies in Europe and Asia. In 1987, Dr. Weisenthal was founder of Oncotech, an Irvine, California oncology-focused laboratory, acquired this year by Exiqon. Weisenthal Cancer Group provides functional tumor cell profiling studies and medical consultation to physicians and patients worldwide in connection with chemotherapy treatment.

The laboratory also provides contract and collaborative research services to biotech and pharmaceutical companies and to cancer researchers.

For additional information, phone Weisenthal Cancer Group at (714) 596-2100 between 9 A.M. and 5:30 P.M., Pacific time, or visit the company’s website at .



The traditional meaning of Health 2.0, according to Jane Sarasohn-Kahn's "Wisdom of Patients" has been the use of social software and light-weight tools to promote collaboration between patients, their caregivers, medical professionals and other stakeholders in health. An example of this in cancer medicine is Individualized Online Clinical Trial Protocol Version 1.0 by the Weisenthal Cancer Group, a Phase II evaluation of individualized cancer treatment with traditional cytotoxic chemotherapy, targeted anti-kinase drugs and anti-angiogenic agents. With most clinical trials, investigators never give out information as to how people are doing. Most trials are failures with respect to actually improving things. The world doesn't find out what happen until after a hundred or 500 or 2,000 patients are treated and then only 24 hours before the New England Journal of Medicine publication date. Individualized Online Clinical Trial Protocol Version 1.0 is a totally transparent clinical trial. Every patient who decides to enter a study should know what happened to previous patients. Patients are treated in real time, on the Internet, with the whole world watching to see how they do. It includes weekly progress reports, and if individual patients want, their own blogs as to how they are doing. Stages have been implemented for a rather innovative clinical trial with cell culture assays, "real time" on the Internet. The purpose of the study is to show that cell culture assay technologies for "targeted" agents really do work. The short-term future of cancer therapeutics is combinations of "targeted" agents. They are not "marketing" the test beyond the confines of a clinical trial, which will be the most transparent clinical trial in the history of oncology, as all results are going to be reported, in real time, on a week by week, patient by patient basis, on the website. E-mail Connie Rueff, the study coordinator. She will answer any questions you may have and will help you to determine if you are a candidate for entry. (714) 596-2100 or [email protected] Gregory D. Pawelski
The Musella Foundation's is doing something similar to what the Weisenthal Cancer Group is doing. Their brain tumor virtual trial keeps track of patients and displays the results "real time" on the web ( You select a tumor type (or all tumors to see more data). Then click on a treatment name and you see all patients who took that treatment + each of the other treatments. Click on a number of patients in each group and you get details of the group. Within this group display, click on a patient id and get their details. But this is the kicker. The Musella Foundation also works on getting insurance companies to pay for these expensive combinations. The most popular one for brain tumors now is cpt-11 and Avastin. It can cost $600,000 a year (perhaps a U.S. Senator could afford that). The Weisenthal website states there are no one-size-fits-all treatments in this trial and no patient unknowingly receives a placebo instead of a promising new drug he/she had hoped to receive. Patient outcomes will be reported online, in real-time, so patients and cancer physicians will learn immediately if and how patients are benefitting from anti-angiogenic, anti-tyrosine kinase, and standard drug combination therapies identified for them by the new test. It is the first clinical trial in which novel combinations of emerging drugs are tested for activity in biopsy specimens obtained from each individual patient. While many of these potentially effective drugs are highly expensive, one problem has been in determining in advance who would benefit from them, how to make the drugs more effective by using them in combination. The effectiveness of these drugs can increase exponentially when they are combined with other drugs in various ways. It is a trial in which each patient receives treatment designed for him/her alone rather than a treatment that serves the financial or research interest of the pharmaceutical company or institution which sponsors traditional clinical trials. Until this new test, no technology existed which allowed for individualized laboratory assessment of candidate drug "combinations" prior to administering them to patients. Gregory D. Pawelski