Liquid biopsies in melanoma – transformation of patient care tantalizingly close

22 February 2017 (Last Updated February 22nd, 2017 11:00)

An innovative blood test is now being used in Melbourne, Australia, which allows the diagnosis of melanoma sooner and gives patients the best chance of survival.

Liquid biopsies in melanoma – transformation of patient care tantalizingly close

An innovative blood test is now being used in Melbourne, Australia, which allows the diagnosis of melanoma sooner and gives patients the best chance of survival. In November 2016, the Olivia Newton-John Cancer Research Institute (ONJCRI) became the first accredited laboratory in Australia to administer this life-saving test. Following on the first FDA approval of a liquid biopsy as a companion diagnostic in lung cancer in 2016, oncologists will potentially be able to make highly-individualized treatment decisions considerably sooner in melanoma as well.

A liquid biopsy essentially involves obtaining a blood sample from a patient, which can then be used to detect fragments of tumor DNA, called circulating tumor DNA. A traditional tissue biopsy in melanoma takes between 2–3 weeks to test for a certain oncogene, called BRAF, whereas a liquid biopsy can be performed in less than three days. To that end, a physician can prescribe a potentially life-saving therapy significantly earlier. Moreover, this pioneering technology requires a minimal amount of blood and is non-invasive, thereby sparing frail patients from unnecessary pain and anxiety. The ability to swiftly screen large volumes of patient samples with unparalleled precision and sensitivity has been made possible by a breakthrough technology called Droplet Digital Polymerase Chain Reaction (ddPCR). Treating advanced melanoma patients as early as possible is critical; after all, the efficacy of systematic therapy is associated with low disease burden.

The potential of this breakthrough technology is obvious; despite significant advances in treatment, the overall survival of advanced melanoma patients remains below 15%. This is due to acquired resistance to systemic treatments, and is driven by tumor heterogeneity and clonal evolution. Thus, a blood test that either detects melanoma with a regional spreading prior to distant metastasis or predicts the effectiveness of a treatment based on a genetic biomarker would be a welcome addition to an oncologist’s armamentarium. ONJCRI has developed the latter, a blood test with prognostic value that is already making headway in improving treatment outcomes.

The melanoma liquid biopsy is available for patients with advanced melanoma, where it tests for specific BRAF gene mutations, which are present in more than 50% of diagnosed cases. In patients testing positive for BRAF mutations, the biopsy can also be used to evaluate clinical response to treatment with BRAF inhibitors, such as Roche’s Zelboraf (vemurafenib) or Novartis’ Tafinlar (dabrafenib), and to dynamically assess tumor progression or recurrence. In patients testing negative for BRAF mutations, the biopsy provides evidence that such a drug would be an ineffective treatment option.

The rapid arrival of new treatments in melanoma and other cancer types can be incrementally facilitated by the routine use of liquid biopsy in the clinic. This powerful assay is expected to become standardized, based on its unprecedented prognostic utility and facilitated by its possible approval in the major markets. Hopefully, it will then be possible to give critically ill patients a better shot at survival.