|Dr. Susan Domchek|
Hereditary genetic tests for cancer have seen their heyday since a U.S. Supreme Court ruling invalidated two of Myriad Genetics' ($MYGN) patents for BRCA1 and BRCA2 genes, opening the door for competition from companies such as Invitae ($NVTA) and Illumina ($ILMN). But now, companies producing the tests are facing pushback from international scientists saying the tools should not be offered to patients until more is known about them.
As Reuters reports, a group of 17 genetics experts is arguing against using the panel tests, saying that "a genomic test should not be offered until its clinical validity has been established," according to a paper published Wednesday in The New England Journal of Medicine. Scientists pointed to lesser-known genes included in the tests, which some experts argue are important to gathering enough data to determine disease risk. But there are not always good risk estimates for mutations that occur in genes used in the tests, leaving doctors and patients wondering what the results mean, according to the Reuters story.
"It's been pretty widely assumed that all of these genes on all of these panels have clear clinical validity," Dr. Susan Domchek, University of Pennsylvania breast cancer expert and one of the paper's co-authors, told the news outlet. "The point of this article was to say, we're not finished with that step yet."
The backlash comes as the government and industry cast a wary eye toward hereditary tests for cancer. The FDA is weighing new regulations for lab-development diagnostic tests, including genetic tests. And earlier this month the U.S. Centers for Medicare and Medicaid Services issued a draft statement calling large panel tests for BRCA genes that include genes not relevant to the patient "not reasonable and necessary," Reuters notes, potentially dealing another blow to companies producing the tools.
Meanwhile, diagnostic companies continue to duke it out for dominance in a fiercely competitive market. Myriad still claims the top-dog role in the BRCA screening market, which accounts for about 80% of its sales. But the company has reported lower profits and waning sales for its cancer tests following the 2013 Supreme Court decision, with rivals such as Invitae and Quest Diagnostics ($DGX) nipping at its heels.