Personalized medicine takes another step forward, as scientists from Pfizer ($PFE) and South Korea make progress developing a diagnostic test that can quickly and cheaply identify patients who can benefit from the company's lung cancer drug Xalkori (crizotinib). Their work is highlighted in The Journal of Molecular Diagnostics.
Xalkori is FDA-approved to treat locally advanced or metastatic ALK-positive non-small cell lung carcinoma, specifically the 1 in 20 patients who have a version of lung cancer where chromosomal aberrations hit the ALK gene in the tumor. An ALK inhibitor such as Xalkori isn't going to be successful unless clinicians can efficiently and affordably identify patients that have the ALK fusion and would benefit most from Xalkori and other drugs like it. But scientists from Pfizer Oncology, working with their counterparts in Seoul National University Hospital in Seoul, South Korea, say they've concocted a diagnostic method that does just that.
They say their assay is far less complex and much cheaper than fluorescence in situ hybridization, or FISH, a standard companion diagnostic test the FDA recently approved to be used with crizotinib. Their test, they note, detects ALK fusions through genetic profiling using technology developed by Seattle's NanoString, which recently gained a CE mark for a gene expression molecular diagnostic test for breast cancer.
The researchers say their lung cancer diagnostic assay matched standards met by FISH and other technology, based on experiments involving using 66 archival non-small cell lung carcinoma samples that had been previously tested by those other, more accepted methods. Importantly, all samples that tested positive for the ALK fusions responded well to the drug.
Of course, the only way a companion diagnostic for a targeted lung cancer drug will be widely used is if it can be quicker, easier and cheaper than existing methods. The researchers say in their study announcement that they've done this, but acknowledge that they have to perform wider-scale tests to make sure their assay can be brought into the regular course of care.
Pfizer has worked hard to develop diagnostics to support Xalkori. Earlier this fall, researchers from Europe and Japan identified a genetic biomarker that could help identify patients in which the drug would most likely stop working--another crucial step in the personalized medicine process.
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