By Diagnostics World Staff
January 21, 2016 | Exosome Diagnostics of Cambridge, Mass., opened sales this morning of its first healthcare-facing product, a blood test intended for patients with non-small-cell lung cancer (NSCLC). The test, called ExoDx Lung(ALK), will be made available to physicians as a laboratory developed test performed in the company’s Cambridge lab space.
Like other “liquid biopsies,” which aim to replace invasive and painful tissue biopsies with simple blood draws, ExoDx Lung(ALK) searches for traces of genetic material shed by tumors into the bloodstream. Exosome’s new test is a fairly conservative application of this technology: it looks only for a specific category of genetic mutations, involving the gene ALK, that are known to impact the course of lung cancer cases. The FDA has approved two drugs, Pfizer’s Xalkori (crizotinib) and Novartis’ Zykadia (ceritinib), for treatment of NSCLC patients whose cancers carry ALK mutations, and physicians might order Exosome’s test to help decide whether these drugs are appropriate for their patients.
Exosome’s approach to liquid biopsy is unique because the company’s technology does not sequence free-floating tumor DNA or isolate whole tumor cells in the blood. Instead, it targets exosomes, tiny packets of waste molecules released by living cells. Tumor cells sometimes give off exosomes containing RNA, which can be sequenced to produce a snapshot of their genetic activity. For its ExoDx Lung(ALK) test, Exosome Diagnostics collects exosomes from blood with a standard kit, then uses proprietary techniques to purify the RNA in these exosomes for sequencing.
The resulting test, Exosome claims, offers a timelier picture of active tumor mutations than liquid biopsies that sequence free-floating DNA. “We’re extremely pleased to be able to offer clinicians this test,” said Vince O’Neill, Exosome’s Chief Medical Officer, in a press release. “We believe this test will provide physicians with the most complete molecular information they need in order to direct patients to the most targeted and appropriate available treatment or clinical trial.”
The ExoDx Lung(ALK) test has a narrower focus than other liquid biopsies on the market, and targets patients who have already been diagnosed, which may help Exosome avoid the negative FDA attention that competitors like Pathway Genomics have attracted. However, the FDA, which does not currently review laboratory developed tests before they are offered to physicians, has made clear that it considers companion diagnostics―tests associated with the prescription of specific drugs―of “high risk” to patients.
Exosome plans to launch blood tests for additional lung cancer mutations later this year, as well as a urine test related to prostate cancer. Exosome also partners with life sciences supplier QIAGEN to sell research use only kits for the purification of exosome RNA.