By Turna Ray

Abbott Molecular plans to contact the British Journal of Cancer to contest the conclusions of a recently published cost-effectiveness analysis involving its Vysis ALK Break Apart FISH Probe Kit.

According to Stafford O'Kelly, president of Abbott Molecular, the authors of the study published in BJC last month based their economic analysis on two erroneous assumptions: the list price charged by labs for the ALK test and the prevalence of ALK rearrangements in the advanced non-small cell lung cancer population. As such, the modeling performed by the researchers to determine the circumstances under which the pharmacogenetic test is cost effective is flawed and should not be considered by healthcare providers and payors, Abbott maintained.

"If clinicians were to act on this article, patients will suffer," O'Kelly told PGx Reporter. "The whole premise of the paper is based fundamentally on very incorrect assumptions."

In the BJC paper, University of Colorado researchers Adam Atherly and Ross Camidge modeled the health economics of administering Pfizer's non-small cell lung cancer drug Xalkori to patients whose tumors are ALK mutation-positive. They found that broadly testing all advanced NSCLC patients in order to identify the small subset of ALK-positive individuals who should be treated with Xalkori did not meet a cost-effectiveness bar of less than $100,000 per quality-adjusted life year gained.

The US Food and Drug Administration last August simultaneously approved Pfizer's Xalkori and Abbott's Vysis ALK Break Apart FISH Probe Kit. The drug costs more than $115,000 per year. The $1,400 price tag for FISH-based ALK testing cited in the BJC analysis was established by "expert opinion" gathered by the researchers.

"Prices for the different tests vary depending on the payer and system. In the US, for example, different insurers reimburse charges at different rates. To limit this complexity, we have therefore taken charges, not reimbursements, as our base values," the study authors detail in the BJC article. "We estimated costs for pathological testing, including both technical and professional fees, utilizing Medicare list prices and the associated University of Colorado charges."

Assuming testing costs within a range of $600 to $1,400 per patient, Atherly and Camidge found that PGx testing for Xalkori is not cost-effective because ALK rearrangements occur in less than 5 percent of advanced NSCLC patients. However, the researchers demonstrated that by applying enrichment strategies to narrow the NSCLC population receiving testing for example, if physicians only tested those NSCLC patients who have adenocarcinoma histology, are non-smokers, and are known to have EGFR and KRAS wild-type tumors payors could potentially more than double the "mean health gain" to around 0.29 QALYs gained per person from 0.013 QALYs gained per person if all advanced NSCLC patients were genetically tested (PGx Reporter 3/21/2012).

In O'Kelly's view, the researchers should not have based their economic modeling on the list price labs charge for the test, but should instead have pegged the analysis to payor reimbursement rates. As the manufacturer, Abbott said it charges labs less than $170 per patient for the ALK FISH test kit. The laboratory then factors in costs associated with performing the test when billing for it.

The lab costs of between $600 and $1,400 cited in the study are "highly exaggerated," O'Kelly asserted. Furthermore, the list price doesn't accurately reflect what payors are reimbursing for the test, which in his view is the most important number when it comes to calculating what a medical intervention costs the healthcare system.

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Abbott Challenges 'Incorrect Assumptions' in Cost-Effectiveness Study of Xalkori PGx Testing