As a Briton, it's always great to see UK innovation and I was pleased to learn today that Cancer Research UK, the world’s largest independent cancer research charity, has spun out a new genomics startup, called Inivata. The company is focusing on the potential for using non-invasive “liquid biopsies”, or blood tests, to detect cancer via circulating tumor DNA (ctDNA).
Inivata has raised funding of £4M / $6.6M to kickstart its efforts and is based in Cambridge, UK. The round was led by Imperial Innovations and also backed by Cambridge Innovation Capital and Johnson & Johnson’s venture capital branch, Johnson & Johnson Development Corporation.
Inivata isn't the first startup to focus on cancer testing and treatment at a molecular level. In the Bay Area of the US, to name just a couple of examples, Guardant Health has been backed by Sequoia Capital and Khosla Ventures to the tune of $40M while Boreal Genomics has raised $24.5M. Clearly there's a lot of work (and cash) going into this area, so what it's all about?
Why do we need "liquid biopsies" and what is ctDNA?
Tissue biopsies don’t work in all situations. They only take a sample from a small area of a tumor, and therefore fail to provide a full picture on how the cancer is developing. Moreover, extracting tumor DNA via invasive biopsies is sometimes impossible. The fragile health of some patients cannot be endangered by the inherent risk of surgery , while the location of some tumors means that sufficient material for genetic testing cannot be obtained.
Consequently scientists have long been researching the possibilities for detecting and monitoring the presence of cancer in a non-invasive way, through blood tests. The success of such tests requires the presence of a circulating biomarker, a substance indicative of cancer that can be traced in the bloodstream.
A range of these biomarkers have now been identified in the genetic data amassed via many genomic sequencing studies and ctDNA is one of them.
When tumor cells are dying, small cell-free fragments of their DNA are released into bodily fluids such as blood plasma. These fragments are circulating tumor DNA, or ctDNA.
Too good to be true?
There are problems with detecting and monitoring cancer in this way. Methods of analyzing the blood need to be very "sensitive" in order to detect the tumor DNA fragments. They also need to work for the majority of patients, without having to be customized on a per-patient basis. Anything else is at best, slow, and at worst, useless.
Researchers are trying to differentiate themselves from the rest of the field by finding a method that achieves both of these aims.
Other scientists employ different approaches. Researchers at the Diehn Lab at Stanford have created a technique called CAPP-Seq which analyzes blood samples for signs of known cancer-related mutations. Stanford neighbor Guardant Health, located in Redwood City, is using another system named Guardant360.
Regardless of method, each organization is driving towards the stage when liquid biopsies become a clinical reality for patients around the globe.