In 2006, Medicare officially recognized cancer chemosensitivity tests as a special test category in Federal Regulations (42 CFR 414.510(b)(3), 71 FR 69705, 12/01/2006). The are now known as Oncologic In Vitro Chemoresponse Assays.
As with any other laboratory tests in cancer medicine, the determination of the efficacy of chemoresponse assays is based on clinical correlations (comparisions of laboratory results with patient response). The "standard" of retrospective correlations between treatment outcomes and laboratory results is sufficient in the case of ALL laboratory tests. It is what established FDA-approval for the test kit.
The decision had been made that the assay is a perfectly appropriate medical service, worthy of coverage on a non-investigational basis. What is of particular significance is that they abandoned the artificial distinction between "resistance" testing and "sensitivity" testing and are providing coverage for the whole FDA-approved kit. Drug "sensitivity" testing is merely a point a little farther along on the very same continuum which "resistance" testing resides.
Cell-based assay tests based on "cell-death" have proven very effective in identifying novel treatment combinations for a variety of cancers. The value of cell-death assays is that they can and do accurately predict clinical outcomes and define novel chemotherapeutic synergies. It can help see what treatments will not have the best opportunity of being successful (resistant) and identify drugs that have the best opportunity of being successful (sensitive).
The current clinical applications of in vitro chemoresponse testing is ever more important with the influx of new "targeted" therapies. Given the technical and conceptual advantages of "functional profiling" of cell-based assays together with their performance and the modest efficacy for therapy prediction on analysis of genome expression, there is reason for renewed interest in these assays for optimized use of medical treatment of malignant disease.
This bio-marker pre-test can help see what treatments have the best opportunity of being successful for "high" risk cancer patients. The test measures the response of "live" tumor cells to drug exposure. Following this exposure, the assays measure both cell metabolism and cell morphology (functional profiling). The integrated effect of the drugs on the whole cell, resulting in a cellular response to the drug, measuring the interaction of the entire genome. Assays based on "cell-death" occur in the entire population of tumor cells.
This cell-based assay technology has been clinically validated for the selection of optimal chemotherapy regimens for individual patients. It is a laboratory analysis based on tumor tissue profiling that uses "fresh" human tumor biopsy or surgical specimen to determine which drugs or combinations of chemotherapeutic agents have the highest likelihood of response for individual cancer patients.
Following the collection of "fresh" tumor cells obtained from surgery or tru-cut needle biopsies, a cell culture assay is performed on the tumor sample to measure drug activity (sensitivity and resistance). This will pinpoint which drug(s) are most effective. Tissue, blood, bone marrow, and ascites and pleural effusions are possibilities, providing tumor cells are present. At least one gram of fresh tissue is needed to perform the tests, and a special kit is obtained in advance from the lab. The treatment program developed through this approach is known as assay-directed therapy.