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Palmetto Releases Draft Coverage Determinations for Several Molecular Diagnostics

NEW YORK (GenomeWeb) – Medicare contractor Palmetto GBA issued several draft local coverage determinations in the last week, including positive coverage decisions for Myriad Genetics' EndoPredict test in breast cancer, CareDx's transplant test AlloSure, and an extension of coverage for Genomic Health's Oncotype DX prostate cancer test to include intermediate-risk patients.

The announcements also included draft LCDs for two types of multiplex infectious disease tests — a decision to provide limited coverage for nucleic acid amplification-based gastrointestinal pathogen (GIP) tests, and a non-coverage decision for multiplex PCR respiratory viral panels — as well a draft non-coverage decision for Prometheus Diagnostics' inflammatory bowel disease test.

Myriad's EndoPredict combines assessment of a 12-gene molecular score with clinicopathological features, like tumor size and nodal status, in order to identify clinically low-risk breast cancer patients who may safely forgo chemotherapy.

Palmetto's draft LCD for the assay includes limited coverage for postmenopausal women diagnosed with early-stage estrogen-receptor (ER) positive, HER2-negative breast cancer, who are either lymph node-negative, or who have up to three positive nodes, and for whom treatment with adjuvant endocrine therapy is being considered.

In the draft LCD, Palmetto mentioned that EndoPredict shares the breast cancer prognostic space with several other molecular tests, including Nanostring's Prosigna and Genomic Health's Oncotype DX Breast.

Interestingly, the LCD for Myriad's test includes data comparing these three assays, which highlights potential differences between them.

For example, the data charted by Palmetto — from the transATAC trial for Myriad and Genomic Health, and from the ABCSG-8 trial for Prosigna — shows EndoPredict classifying 73.4 percent node-negative patients as low-risk, compared to 63.5 percent for Oncotype DX, and 48.2 percent for Prosigna.

Among node-positive patients, EndoPredict yielded a low-risk result in 19 percent of patients, while Oncotype DX saw a low-risk result in 56.9 percent of patients, and Prosigna saw similar results in only 4.1 percent of patients, according to the data cited by Palmetto.

Recurrence rates by risk group appeared to differ significantly for the three tests in these calculations, as well.

In a separate draft LCD, Palmetto expanded its coverage decision for Oncotype DX's prostate cancer test to include intermediate, as well as clinically low-risk, patients.

The contractor finalized its favorable LCD for the test in the low-risk setting in 2015.

Palmetto also issued a draft decision for intermediate patients for Oncotype DX's main competitor in the space — Myriad's Prolaris, last December.

For CareDx's AlloSure — a targeted next-gen sequencing test that quantifies donor-derived cell-free DNA in kidney transplant recipients — Palmetto's new draft decision proposes limited coverage to measure the probability of allograft rejection in kidney transplant recipients for whom there is a clinical suspicion of rejection at least two weeks post-transplant.

Other clinical conditions include that patients must be more than 18 years old, and that physicians must assess their patients for the probability of active renal allograft rejection before ordering AlloSure.

Palmetto explained in the draft LCD that the evidence of clinical utility for the use of AlloSure is currently limited, but said that it expects forthcoming prospective clinical studies to demonstrate improved patient outcomes. In that light, continuing coverage for the test would be dependent on annual review by the contractor of this expected new data.

A fourth LCD this week proposes coverage for molecular assays that use nucleic acid amplification to detect gastrointestinal pathogens, limited to up to five bacterial targets that represent what Pametto said are the top 90-95 percent of foodborne infections — Salmonella, Campylobacter, Shigella, Cryptosporidium, and Shiga toxin-producing E. coli.

The contractor cited a number of US Food and Drug Administration-approved gastrointestinal pathogen assays that either meet or exceed this five-target limit, including Hologic's ProGastro SSCS, BD Diagnostics' BD MAX Enteric Bacterial Panel, Nanosphere's Verigene Enteric Pathogens assay, Luminex's xTAG Gastroenterology Panel, and Biofire Diagnostics' FIlmArray GI Panel.

Under the draft LCD, Palmetto proposes coverage for the five mentioned bacterial targets, but not for viruses, because of a lack of virus-specific therapies that such testing would inform. The coverage also would not include testing in the context of national, state, or local agency testing for epidemiologic purposes or to confirm another test result, Palmetto wrote.

Furthermore, panels cannot be unbundled and billed as individual components, the contractor said. However, if C. difficile is not included in a GIP panel, "testing for C. difficile may be reasonable and necessary when ordered" additionally, as long as it's supported by documentation in the medical record.

While Palmetto proposed covering GIPs, another draft LCD chose the opposite approach for multiplex PCR testing for respiratory viruses, apart from direct probe techniques for influenza A/B, with or without inclusion of respiratory syncytial virus (RSV).

Reasoning for non-coverage included the fact that the pathogen targets in such panels don't represent a common syndrome, and that targets can be very rare.

"A panel that includes pathogens that are very rare, or a panel in which all pathogens do not cause overlapping clinical syndromes, or when some pathogens are found only in specific patient populations (immunocompromised patients) is not reasonable and necessary," Palmetto wrote.

Examples include Chlamydophila pneumoniae or Bordetella pertussis in combination with rhinovirus, influenza viruses, and RSV

Other assays that detect influenza A and B, with or without RSV are, however, a Medicare covered benefit, Palmetto said.

"The multiplex PCR respiratory viral panels are effectively a 'one-size-fits-all' diagnostic approach, and do not meet Medicare’s 'reasonable and necessary' criteria," Palmetto said.

Finally, Palmetto also issued a draft non-coverage decision for the Prometheus IBD sgi Diagnostic test, which is intended to aid healthcare providers in differentiating inflammatory bowel disease from Crohn's disease, ulcerative colitis, or other non-IBD symptoms, using a panel of nine serological markers, four genetic immune response markers, and five inflammatory biomarkers.

According to the Medicare contractor, while manufacturer data supports clinical validity of the test for diagnosing IBD, this evidence is "insufficient to support an indirect chain of evidence for clinical utility, due to lack of details about study methodology and lack of replication of the findings."

Furthermore, clinical validity has not been established by Prometheus for distinguishing UC from CD, and there are no US Preventive Services Task Force recommendations for genetic or molecular testing for inflammatory bowel diseases, or for multimarker panels to facilitate diagnosis or prognosis of CD or UC.

"Consequently, this assay is does not meet Medicare’s reasonable and necessary criteria for coverage," Palmetto wrote. Apart from ASCA-IgA, ASCA-IgG, and atypical perinuclear antineutrophil cytoplasmic antibody, the individual biomarker components that comprise the assay are also non-covered for the IBD diagnosis.