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Palmetto Releases Draft Coverage Determinations on Several Cancer Molecular Diagnostics

NEW YORK (GenomeWeb) – Medicare contractor Palmetto GBA issued a draft local coverage determination yesterday stating its plans to stop covering the rheumatoid arthritis test Vectra DA and another draft proposal to extend coverage to Prolaris for patients at intermediate risk for prostate cancer.

Myriad Genetics' Prolaris measures prostate cancer aggressiveness based on the expression of 31 cell cycle progression genes. Myriad subsidiary Crescendo Biosciences' Vectra DA analyzes the levels of 12 markers associated with inflammation due to rheumatoid arthritis, and the test score allows tracking of disease activity and the extent to which patients are responding to treatment.

In the draft LCD discussing its rationale for proposing non-coverage for Vectra DA, Palmetto said there is conflicting data regarding the validity of the test, citing a study in which researchers concluded that the Vectra DA score did not reflect disease activity in a rheumatoid arthritis trial, called AMPLE, and should not be used to guide decision making. This study "raises concerns about the efficacy of the test as designed," Palmetto wrote in the draft LCD. 

In response to Palmetto's decision on Vectra DA, shares of Myriad dropped around 5 percent to $16.71 in early Friday afternoon trading on the Nasdaq.

In a statement, Myriad said it "strongly disagrees" with the conclusions of AMPLE, and highlighted that the study had "shortcomings," such as the use of an "unconventional statistical analysis of radiographic progression." However, when the data in this study are analyzed according to more conventional methods, the Vectra DA score does predict radiographic progression in patients with rheumatoid arthritis, the company said.

The Medicare contractor also pointed out that the 2015 American College of Rheumatology treatment guidelines don't mention biomarker testing, but state that a "functional status assessment using a standardized, validated measure should be performed" at least once a year or more often in cases of active disease. Palmetto would like to see additional evidence on Vectra DA, and noted the lack of prospective clinical trials on the clinical utility of the test.

Myriad highlighted that Vectra DA's efficacy has been shown in more than 20 studies involving over 3,000 patients, and that the majority of rheumatologists have ordered it for approximately 300,000 patients in the US. Moreover, Vectra DA is in guidelines issued by United Rheumatology and will be evaluated for possible inclusion in the American College of Rheumatology guidelines.

In the case of Prolaris, Palmetto wants to cover the test when men have favorable intermediate risk of prostate cancer, according to the National Comprehensive Cancer Network's guidelines. The Medicare contractor acknowledged that there is limited evidence on the test's clinical utility in this population at this time, but noted there are a number of prospective studies underway that can "firmly establish" whether the use of the test can help identify low-risk patients who can avoid unnecessary invasive procedures.

Myriad saw this determination as a positive event that would start impacting its revenues in fiscal year 2018. "This draft LCD, if approved, would expand coverage for about 15 percent of men or approximately 30,000 additional men per year in the United States," the company said in a statement.

Last year, Palmetto and another Medicare contractor Noridian issued a final LCD for Prolaris when used for low- and very low-risk prostate cancer patients according to NCCN guidelines. 

In a note to investors, Piper Jaffray analyst William Quirk estimated that Prolaris coverage in intermediate-risk patients is a $65 million market. Meanwhile, if the LCD for Vectra DA stands then that could negatively impact Myriad's revenues by $35 million to $40 million. Stakeholders can comment on these draft LCDs from Feb. 6 to March 23.

Additionally, Palmetto issued two draft LCDs yesterday proposing limited coverage for Integrated Diagnostics' Xpresys Lung proteomic test and Castle Bioscience's DecisionDx-UM.

Xpresys is a blood test that combines the expression levels of two proteins and five clinical risk factors to determine which lung nodules are likely benign, and who can receive surveillance with noninvasive computed tomography and be spared invasive surgical interventions. Palmetto is proposing to limit coverage of the Xpresys Lung version 2 (XL2) test to manage assessment of lung nodules between eight and 30 mm in diameter in patients older than 40 who have a pre-test cancer risk of 50 percent or less.

DecisionDx-UM is a tissue-based test that gauges the expression levels of 15 mRNA transcripts and is intended to be used to determine whether a patient newly diagnosed with uveal melanoma is at risk for metastatic disease. Palmetto is limiting coverage to newly diagnosed patients and noted in the draft LCD that the test should be used to discern which patients need further surveillance and should be referred to a specialist.

Both of these draft LCDs contain extensive tables on the specifications of these tests, including intended use, analytical performance, clinical validity, and utility. The level of detail and format of this information is reminiscent of labeling issued for a test after approval or clearance by the US Food and Drug Administration.

However, the majority of lab-developed tests will likely not have this kind of labeling since the FDA recently said it will hold off on finalizing its plans for broad oversight of such tests. If Palmetto continues to present detailed test specifications in future LCDs, it will be an important source of information for physicians and patients in the absence FDA-approved labeling.

Members of the public can comment on these draft LCDs from Feb. 6 to March 23.