Endometriosis: What is this “promising” and “innovative” saliva test that should soon become available?

To reduce the diagnostic bias faced by many women with endometriosis, the Higher Health Authority (HAS) is opening the door to saliva testing, which is considered “promising” but awaits new data before widespread reimbursement is possible. Developed by the Lyon biotech company Ziwig, the test, called Endotest, “showed very good diagnostic performance,” emphasizes HAS, which took steps to evaluate its effectiveness and clinical utility.

Endometriosis, a chronic condition that affects about one in ten women, usually results in severe pain during menstruation and/or fertility problems. Even today it is diagnosed, often by accident, with an average delay of seven years. Reducing that delay to just a few days with a saliva test aimed at symptomatic women is a “revolution,” the startup founder praises.

How does the test work?

“Our test allows us to put a name to common and disabling symptoms,” says Yahya El Mir, founder and president of Ziwig. “To do this, you need to take a little saliva, which contains microRNA,” he explains. Because endometriosis “is not a purely gynecological disease.”

By collecting saliva, one can “get as close as possible to the biological functioning of cells and obtain information that cannot be obtained through imaging or surgery, which allows for a reliable biological diagnosis,” he still claims.

What do doctors think?

“The technique used is attractive because the test is very simple,” says Louis Marcellin, a gynecologist at Cochin Hospital (AP-HP). The test then involves performing high-throughput sequencing and using an algorithm developed by artificial intelligence. A year ago, Inserm (National Institute for Health and Medical Research) remained cautious about the results of the first study, which included just 200 patients.

On Monday, the Supreme Health Authority published its conclusion, based on the extension of the same study to more than 1,000 women suffering from pelvic pain. Her evaluation found the diagnostic accuracy of the test, which she considers “promising” and “innovative,” to be 95%.

While acknowledging patients’ “high expectations” for this test, HAS emphasizes “the need for more research to assess its clinical utility in current practice.” Consequently, it initially offers early access through the so-called “innovation” package.

Free test? Are you paying?

Specifically, if the government follows HAS advice, women over 18 who are “strongly suspected of having endometriosis” will be able to take the test for free. Support is “conditional” for participation in new studies, which will allow a decision to be made in favor of long-term reimbursement or not. “We are especially looking forward to finding out whether this test will allow us to improve treatment strategies,” we explain to HAS.

For patients, marketing and paying for the test can be a “game changer,” says Priscilla Saracco, executive director of the Endomind Association. “In addition to delays in diagnosis, there are large spatial inequalities today: women do not have access to expert centers or trained radiologists,” she adds.

What are the results abroad?

Endotest has been sold in about ten countries in Europe and the Middle East for more than a year. For example, in Switzerland it sells for about 800 euros.

“There is no more accurate method than this test,” says Hervé Fernandez, a gynecological surgeon and professor emeritus at the University of Saclay in Paris. “But we have to ask ourselves what we will do with our results, what treatment we will be able to offer then.”

There is currently no definitive treatment for endometriosis, although hormone therapy and/or surgery can sometimes stop its progression. Sivig is working on a second version of the test, which will be able to clarify the characteristics of the disease depending on the patient (superficial form of endometriosis, increased risk of infertility, etc.), and adjust treatment.