By Kirell Lakhman

Blue Shield of California will now cover a test made by XDx designed to monitor heart-transplant rejection more than one year post-transplant.

With BSC saying the gene-expression-based AlloMap is "medically necessary," most stable heart-transplant recipients on its rolls will no longer have to undergo organ-function biopsies.

There are about 2,100 heart transplants performed each year in the US and approximately 20,000 living heart-transplant recipients.

AlloMap was developed as a backstop against ineffective immunossuppression. Though better immunosuppressive treatments have increased survival rates for heart-transplant patients, the risk of acute cellular rejection remains for several years post-procedure.

And, like most therapeutics, over time drugs used for immuno-modulation like cyclosporine, 6-mercaptopurine, and methotrexate lose their efficacy over time. To guard against this, heart-transplant patients undergo endomyocardial biopsies for years after they receive their new organs.

With BSC's coverage decision, many patients on the payor's rolls will no longer have to endure the painful, risky procedure.

The qRT-PCR-based assay, which is performed in XDx's CLIA lab in Brisbane, Calif., is designed to be used with standard clinical assessment to help cardiologists identify heart-transplant recipients with stable allograft function who have a low probability of moderate-to-severe acute cellular rejection.

Commercially available since 2005 and FDA-cleared three years later, the assay interrogates mRNA levels of 20 genes — 11 reporting and nine that are used for normalization and/or quality control — to yield gene-expression data that becomes a score comprising an integer ranging from 0 to 40. The lower the score, the lower the probability of acute cellular rejection at the time of testing.

The 11 reporting genes are ITGA4, PDCD1, MARCH8, WDR40A, PF4, C6orf25, IL1RN, ITGAM, FLT3, SEMA7A, and RHOU.

BSC's decision follows other recent coverage wins for AlloMap this year. In June Anthem Blue Cross and Blue Shield began reimbursing for it while Aetna starting its coverage in March.

Last year was also a potential growth driver for AlloMap. In August 2010 the International Society of Heart and Lung Transplant called the assay "the new standard of care for stable heart-transplant patients,” and in November the California Technology Assessment Forum "recommended" it.

In addition, last February XDx penned a multi-year agreement with LabCorp that allows AlloMap patients to have their blood drawn at participating LabCorp sites in the US. This isn't so much a volume-driving deal, but it will certainly make life easier for patients whose ability to travel is limited.

Yet despite AlloMap's increasing private-payor coverage and growing blessings from international transplant organizations, it still hasn't reached the level of adoption XDx had expected. The reason, ironically, is financial.

As my colleague Turna Ray wrote in April in Pharmacogenomics Reporter, an XDX official recently argued that physicians "don't have a monetary incentive" to use it in place of biopsies.

The biopsies that cardiologists currently perform — in which they thread a thin catheter from an artery in the patient's groin directly into the heart — are sophisticated and costly procedures with very high reimbursement rates.

With AlloMap, cardiologists don't see a nickel of reimbursement because there is no reimbursement for writing a script for the test.

"Comparative effectiveness and strong clinical validation don't always ensure rapid and broad-scale adoption," Matthew Meyer, VP of corporate business development at XDx, told PGx Reporter during a personalized medicine meeting in April. "Financial incentives can often be very critical."

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