Grail raises more funds to advance a blood-based cancer test

The cancer detection start-up Grail, formed in 2016 by the DNA sequencing giant Illumina, has raised $300 million from a suite of Chinese investors. The latest cash infusion brings the company’s total funding to over $1.5 billion.

Grail is developing a version of the liquid biopsy, a technique that could allow doctors to detect cancer by sequencing bits of cell-free DNA floating in the blood. This DNA, presumably leaked from dead or dying cells, is not well understood. A DNA fraction from cancer cells, called circulating tumor-derived DNA (ctDNA), could provide an early sign of cancer long before doctors spot a tumor.

Detecting such a small signal in a sea of noise won’t be easy. Last year, Grail scientists estimated they may need to collect data from tens to hundreds of thousands of people (Cell 2017, DOI: 10.1016/j.cell.2017.01.030). So far they’ve enrolled more than 73,000, about half the 135,000 the firm hopes to register in its two ongoing studies by the end of the year.

The first trial, called the Circulating Cell-Free Genome Atlas Study (CCGA), will look for similarities and differences in ctDNA signals across many kinds of cancer. Grail aims to collect blood and tumor samples from 10,500 people recently diagnosed with cancer and blood samples from 4,500 people with no history of cancer.

The second trial, called STRIVE, will collect blood samples from about 120,000 women receiving breast cancer screening. Both studies will follow all participants for five years. The resulting massive datasets—about a terabyte of genomic information per person—will help Grail compare ctDNA patterns in the blood of people who have cancer with those who don’t.

In the meantime, Grail will launch its first commercial blood test, for nasopharyngeal cancer, in Hong Kong, where the disease is prevalent. Grail obtained the blood test when it merged with the Hong Kong-based company Cirina in May 2017.

Cirina was cofounded by Dennis Lo, a researcher at the Chinese University of Hong Kong, who led a study to identify nasopharyngeal cancer by detecting DNA from the cancer-associated Epstein-Barr virus in the blood (N. Engl. J. Med. 2017, DOI: 10.1056/NEJMoa1701717). While the trial was heralded as one of liquid biopsy’s first success stories, most cancers won’t have the same smoking-gun evidence that the virus provides for nasopharyngeal cancer.