Accurate, Useful, Clinically Validated

There is scarcely an oncologist who would not acknowledge the need for laboratory tests to guide selection from among an ever expanding armamentarium of increasingly expensive though not universally effective chemotherapy agents.  It is hardly possible these days to receive FDA drug approval for a new drug absent the parallel introduction of a companion pharmacodiagnostic test to guide patient selection.  The need was felt no less keenly in the early 1980’s when all hope in the oncology community was affixed to a single cell culture technology – the clonogenic, or human stem cell, assay.  And when that one particular technology was found to be lacking in some ways and misunderstood in others oncologists became disillusioned with the entire concept.

Thirty years farther along oncology has changed dramatically but the need for tests to guide therapy selection has only increased.  In that time new cell culture methods were developed that circumvent the shortcomings of the early cell colony forming methods.  The newer methods are based on induction of cell death in the entire tumor cell population, a far more appropriate endpoint considering what is now understood about apoptosis and its critical role both in tumorigenesis and in cytotoxic drug therapy.  Many other equally dramatic changes have occurred over the past 25 years in the development of these tests – and the tests themselves have been subjected to rigorous scrutiny in more than 100 peer-reviewed, uniformly positive studies.  And yet some reviewers pointedly ignore the new technologies and supporting studies and instead base conclusions upon technologies and methods abandoned by nearly everyone 20 years ago.  Clearly, the topic impels thoughtful re-examination.  We strive on this site to provide clinicians and patients only with supportable facts. We believe these speak for themselves.  We are comfortable in allowing any reviewer acting in good faith to reach his or her own conclusion.      

Cytometric Cancer Profiling Studies are Comparable in Accuracy and Clinical Utility to ER/PR and Other Essential Tests in Oncology

The standard for evaluating laboratory tests has always been accuracy, reproducibility, and utility.  The standard has never been treatment outcome.  For example, estrogen and progesterone receptor testing (ER and PR) to guide the use of hormonal therapy drugs such as tamoxifen has never been shown in a prospective randomized trial to improve response or survival in breast cancer.  It is not that the studies were performed and the tests failed to show treatment benefit – rather, it is only that prospective, randomized trials are never carried out for the purpose of showing that outcomes are improved by performing certain laboratory tests.  On the other hand, no physician would be surprised to learn that ER expression has been shown - in retrospective studies - to correlate reliably with response to hormonal treatments. 

ER, PR and many other tests are viewed as invaluable.  This is because the tests are accurate and reproducible and – based upon retrospective correlation studies - the tests are known to correlate reliably with the clinical or biological phenomena they are intended to detect, measure, or predict. 

In all of oncology no test has ever been shown in a prospective, randomized clinical trial to improve clinical outcome.  Except for one.

Cytometric Profiling Produces Superior Survival in a Randomized Trial

In a landmark study involving the use of cytometric profiling in the setting of relapsed chronic lymphocytic leukemia there was a 2.5-fold greater mortality at one year in the group receiving standard, empiric therapy (Protocol arm) compared to the group receiving cytometric profiling-directed therapy (DiSC/TRAC Assay arm). (20% mortality in the Protocol arm versus 8% mortality in the DiSC/TRAC assay arm, p=0.04)1

This is the first-ever trial in which a laboratory test was held to the unprecedented standard of improving overall survival in cancer.  The results of this study are consistent with those of hundreds of other studies, in which treatment with drugs found active in cytometric profiling assays correlated positively with higher rates of response, progression-free survival, and overall survival.

Consistently Positive Assay Correlation in 150 Published Studies

Cytometric Profiling has been subjected to greater scrutiny in clinical trials than most other tests used routinely in oncology – not only in terms of the number of studies of cytometric profiling ccuracy and reproducibility but also with respect to correlation with clinical outcomes.  Data from more than 150 studies uniformly demonstrate positive correlation between prospective predeictions of drug activity and patient chemotherapy response - and also, where such follow-up data are available, with both progression-free and overall survival.  In meta-analysis of cell death-based cytometric profiling studies, an assay “positive” drug was 7.5 times more likely to produce objectively-measured patient response than an assay “negative” drug. 

Cytomettic profiling can identify for each patient those drugs that have higher than average likelihoods of producing clinical benefit.  It also shows which drugs have lower than average likelihoods of producing clinical benefit.  The claim is modest and unambiguous.  Study after study has borne out the claim and no person who is familiar with the large body of published literature which supports cytometric profiling has ever disputed it.  Many physicians today order the tests routinely for their patients because they continually see real clinical benefit. 

In February 2007, National Heritage Insurance, the Medicare administrator for the state of California, concluded a year-long, comprehensive review of data relating to cytometric profiling and ruled in favor of full coverage of the service for Medicare patients, even after taking into consideration an earlier and much-publicized ASCO review.  One reason National Heritage rejected the ASCO position is because the ASCO reviewers admitted that they selectively had ignored precisely those data which are most relevant: the data which demonstrate the accuracy, reliability, and perceived utility of cell death-based cytometric profiling profiling. 

In omitting data pertaining to cytometric profiling test accuracy, the ASCO review panel sought to impose criteria which never before had been applied to any laboratory test. 

However, there is even more to consider when weighing the position of ASCO’s review.  

ASCO Review Focuses on Discarded Methods

ASCO’s recommendations were based upon its review of 12 previously published clinical studies involving only cell-growth (aka clonogenic or cell proliferation) assay methods even though these were largely abandoned 20 years ago. Drug induced cell-death as a surrogate for apoptosis is the most relevant biological measure.  It was orginated by Dr. Weisental and is the method used most widely today, worldwide.  The panel did not review cell-death assays and failed even to acknowledge that a critical difference exists.  And yet there have been dozens of studies of cell death assays, producing the overwhelming majority of cytometric cancer testing data published in the past two decades.

ASCO Review Contrives Standards Unprecedented for any Laboratory Test     

Not only did the ASCO panel fail to discriminate studies of Cell Death assays from studies of Cell Proliferation assays, the ASCO panel pointedly cast aside all evidence of assay accuracy.  The reviewers openly admitted, “We excluded reports that only reported correlations between assay results and clinical outcomes.”  In other words, the ASCO panel deliberately ignored the most critical standard applied to all medical laboratory tests.

Failure to Inform or Consult Recognized Experts

Another troubling aspect of the ASCO review relates to the composition of the ASCO panel and specifically to the qualifications and potential conflicts of interest of the reviewers.  No investigator actively working with PCC profiling technologies incorporating the new-generation, cell-death endpoint was included on the panel - all had links to the older and largely abandoned methods.  Even more glaring in its bias is the fact that no such cell-death assay expert was even consulted.  This would have been very easily accomplished because the cell death endpoint is now used by nearly every reputable investigator in the field who has published within the last ten years.  In fact, no notice of any sort was accorded to the many dedicated researchers in this field that such a review even was contemplated.  Instead, the panel acted in secrecy. 

Not only was no outside PCC research expert consulted, not a single physician was consulted from among the many who are ASCO’s own members and who use Personalized Cytometric Profiling routinely to assist in choosing chemotherapy drugs for their patients.     

One such experienced PCC user is a well-respected medical oncologist, an ASCO member, and former President of his state's medical oncology society.  His statement appears in the written record of a CMS/Medicare hearing:

“My experience with cell death CSRAs [the term used in the ASCO review to describe personalized cytometric profiling] is that they have accuracy in predicting clinical outcomes and defining novel chemotherapeutic synergies. They also have frequent curative value in treating many adult malignancies which the current medical literature has deemed incurable…I believe that it would be unethical for me not to use such CSRAs in my practice.”

We believe that the composition of the panel, along with ASCO’s failure to seek comment from respected experts in the field - or even from oncologists who use the tests - coupled with the deliberate exclusion of the entire body of the most highly relevant data created a bias which is not consistent with a balanced and credible technology assessment. 

ASCO vs. Medicare -         Two Ways to Conduct a Technology Review

Contrast the ACSO approach with that of Medicare Administrator, National Heritage Insurance Company (NHIC) which conducted its own technology assessment.  NHIC held several open and well-publicized hearings - reaching-out to gather testimony and scientific evidence from physicians, PCC researchers and experts, drug companies, and also from PCC critics.  All interested parties were invited to attend and participate.  NHIC spent an entire year reviewing the full body of published PCC data and especially seeking the advice of independent physicians who have actually used PCC in their medical practices.  The technology assessment was personally headed by the Medical Director of National Heritage.  The result was a Local Coverage Determination in which PCC became fully-approved for Medicare beneficiaries. 

Note that this coverage determination was  reversed some years later by Palmetto Blue Cross of South Carolina when it was appointed Medicare Administrator for the state of California.  Palmetto never undertook its own technology review, as did National Heritage, but instead, ironically, relied only upon the flawed ASCO review.  Thus, as of this writing, Medicare beneficiaries and, in many cases, patients with private insurance, are once again deprived of payment for - and thereby access to - these potentially life-extending PCC technologies.  To contrast the findings of National Heritage’s openly-conducted and unbiased review versus the closed and highly-skewed (we hold that it was skewed by ASCO’s admitted censorship of highly-pertinent data and also by its failure to seek independent testimony) but much more highly-publicized ASCO review.

References

Matutes E, Bosanquet AG, Wade R, et al, The use of individualized tumor response testing in treatment selection: second randomization results from the LRF CLL4 trial and the predictive value of the test at trial entry. Leukemia (2013) 27, 507–510; doi:10.1038/leu.2012.209. 

Abelson R. Pay Method Said to Sway Drug Choices of Oncologists, New York Times, March 8, 2006.


Ellis, R. Cancer Docs Profit from Chemotherapy Drugs. NBC Nightly News, September 21, 2006.


Jacobson, M., O'Malley, A.J., Earle, C.C., et al. Does Reimbursement Influence Chemotherapy Treatment For Cancer Patients?, Health Affairs 25(2):437-443, 2006.


Click here to view a copy of Dr. Weisenthal's curriculum vitae.