Liquid License

Lung cancer is the leading cause of cancer deaths among both men and women, and with non-small cell lung cancer (NSCLC) being the most common type, it’s no surprise that plenty of attention is focused on finding ways to treat it. In particular, tailoring treatment and diagnosis has been a key aim of most researchers active in the field and one major step forward in this regard has been in the development of the drug erlotinib, which inhibits the epidermal growth factor receptor (EGFR) and has proven to be maximally effective in NSCLC patients with EGFR gene mutations. As with many mutation-targeting therapeutics, the hunt for an effective accompanying diagnostic has been ongoing, and one such test has proven itself worthy of a Food and Drug Administration (FDA) seal of approval – the first diagnostic of its kind to get the nod from the US regulators.

Noninvasive, blood-based tests, or liquid biopsies as they are commonly known, have garnered a lot of attention recently, in particular because of their noninvasive nature. These tests involve detecting DNA shed by tumors into patients’ blood, allowing tumor DNA to be sequenced and examined without the need for an invasive and potentially risky tissue biopsy. Until recently, such tests were in their experimental stages, but as of June 1st, the FDA issued its first-ever approval for a liquid biopsy test (1). The cobas EGFR Mutation Test v2 is a companion diagnostic to erlotinib, which is FDA-approved for first-line treatment in patients with specific EGFR mutations (either an exon 19 deletion or an L858R substitution).

Although NSCLC accounts for over 1.5 million cancer diagnoses per year worldwide (2), this test approval is just the first step on a long road. If the trend continues, we may soon see liquid biopsies designed to detect mutations in a wide range of cancers, helping medical professionals personalize each patient’s treatment based on their tumor’s genetic profile – all without the need for tissue sampling.