By Diagnostics World Staff
March 6, 2018 | FDA today authorized a direct-to-consumer genetic test for cancer risk. The authorization allows 23andMe to provide customers, without a prescription, information on three genetic variants found on the BRCA1 and BRCA2 genes known to be associated with higher risk for breast, ovarian, and prostate cancer.
At the 23andMe blog, Anne Wojcicki, 23andMe CEO and co-founder, called the approval a “major milestone.” FDA, however, peppered its press release with caveats. “The test only detects three out of more than 1,000 known BRCA mutations. This means a negative result does not rule out the possibility that an individual carries other BRCA mutations that increase cancer risk,” FDA stated. “These three mutations, however, are not the most common BRCA1/BRCA2 mutations in the general population.”
The three variants that 23andMe will report on are most prevalent in those of Ashkenazi Jewish descent, and have been observed at much lower rates in other ethnicities. About 1 in 40 individuals of Ashkenazi Jewish descent has one of these three variants. Women with one of these variants have a 45-85% chance of developing breast cancer by age 70.
In the 23andMe press release announcing the news, Wojcicki emphasized that family history and descent are not always known. “This authorization is incredibly valuable for those who might not be aware of their Ashkenazi Jewish descent or aren’t familiar with their family history of cancer.”
On the 23andMe blog, Wojcicki said that the authorization is, “a significant step forward for consumers who want direct and affordable access to their health information. Over the last four years, it has kept me up at night knowing that we have customers with one of these risk variants but have been unable to tell them. I can sleep better knowing that soon, if our customers choose to, they can view this information. We know from our own data that this information can be incredibly meaningful for customers and, in some cases, could even save lives.”
New and existing 23andMe Health + Ancestry Service customers that were genotyped on the company’s most recent platforms will have access to this report in the coming weeks, the company said. As with select other Genetic Health Risk reports, customers must specifically choose for themselves if and when they want to receive this information. The report also includes an education module to ensure customers are fully informed on what they can learn from this report and how to use the results.
As part of the review process in order to establish safety and effectiveness for this authorization, 23andMe reportedly demonstrated a high level of accuracy (greater than 99% concordance to Sanger sequencing) and precision (demonstrated by studies yielding greater than 99% reproducibility and repeatability).
FDA took pains to spell out what consumers should not do with test results. “Consumers and health care professionals should not use the test results to determine any treatments, including anti-hormone therapies and prophylactic removal of the breasts or ovaries. Such decisions require confirmatory testing and genetic counseling,” the FDA statement reads. “The test also does not provide information on a person’s overall risk of developing any type of cancer. The use of the test carries significant risks if individuals use the test results without consulting a physician or genetic counselor.”
23andMe did its part, cautioning in its press release that the test does not preclude regular cancer screenings. “It’s important to understand that the majority of cancer is not hereditary, our test does not account for all genetic variants that can cause a higher risk of cancer, and people should continue with their recommended cancer screenings.”
But 23andMe contends that broader testing—regardless of known family history or ancestry—is important. And it is in good company. Current clinical guidelines for genetic risk evaluation are based primarily on personal and/or family history of certain cancers. However, a perspective by Mary Claire-King, Ph.D published in The Journal of the American Medical Association has argued for broader access, citing a study where “50 percent of families found to harbor BRCA1 or BRCA2 mutations had no history of breast or ovarian cancer that would have triggered clinical attention.
Consistent with those previous findings, 23andMe found that of those BRCA carriers who gave family medical history, about half reported no history of cancer in first-degree relatives. 23andMe has also observed that many of its customers for whom Ashkenazi Jewish ancestry was detected, did not self-report any Jewish ancestry. These individuals might fall outside the guidelines of clinical testing.
This authorization is the third de novo authorization granted by the FDA to 23andMe. In February 2015, 23andMe was granted authorization by the FDA to market the first direct-to-consumer genetic test for Bloom Syndrome under the de novo pathway which has since enabled the company to bring 40+ carrier status reports directly to customers. These reports convey risk for diseases that may be passed to offspring. In April 2017, 23andMe was granted authorization by the FDA to market the first direct-to-consumer genetic health risk reports, to date the company has launched 9 reports for a variety of genetic health risks.