UrSure Seeks to Boost PrEP Adherence with Urine Tests

Giffin Daughtridge, MD

A new startup is aiming to make it easier for physicians to know if patients at high risk for HIV are taking pre-exposure prophylaxis regularly. UrSure Inc. says its urine test will also give patients peace of mind from the confirmation that PrEP is working.

Giffin Daughtridge, MD, UrSure’s co-founder and CEO, said the company’s PrEP adherence urine test is designed to be a simple solution to a problem that can be difficult to solve—knowing for sure whether a patient is actually taking the pill as prescribed.

“By far the most common way of doing it right now is patient self-reports—just asking a patient,” he told MD Magazine®. “Obviously that’s an issue both because it’s tedious and because it’s incredibly inaccurate.”

There are other ways to test if a patient has taken PrEP recently, such as dry blood spot tests, hair tests, and plasma tests, but he said those are more costly and inconvenient than a urine test.

UrSure’s solution is a mass spectrometry test, by which the company analyzes a patient’s urine sample and reports back to providers within 3 days. Daughtridge says their urine test stood up well against a plasma test in a proof-of-concept study published in 2017.

In that study, which was funded in part by the National Institutes of Health, the urine test was able to distinguish the presence of PrEP with a greater sensitivity than plasma tests.

Specifically, a concentration of the drug of greater than 1,000 nanograms per milliliter of urine was found to correlate with a presence in the plasma of at least 10 ng/mL, an amount that suggests the pill was taken within the past 48 hours. The study also demonstrated that a concentration of less than 10 ng/mL in the urine was solid evidence of nonadherence (defined as taking no doses within the past 7 days).

In other words, the test can show physicians 3 possible scenarios: patient adherence, partial adherence (PrEP within the past week but not the past 48 hours), and non-adherence.

That information can help providers tailor interventions to the patient, Daughtridge said. He said non-adherent patients in the high-risk category for HIV, such as young men of color who have sex with men, often fall into 1 of 2 categories: people who have trouble accessing the medication and people who can access it but have trouble sticking with the plan.

In the case of the first category, Daughtridge said, the problems could be related to insurance or transportation, among other causes. In many communities, services are available to solve both problems, but a physician would first need to know such services are needed by the particular patient. An adherence test like UrSure’s can help initiate such a conversation.

In the second category—access without adherence—the lack of adherence could be due to issues such as homelessness, drug addiction, or stigma. Again, interventions are available in many communities that could alleviate or solve such problems.

One concern Daughtridge and colleagues had as they developed the test was that some patients might think of it as a “lie detector” or a means by which a suspicious doctor could catch a non-adherent patient. However, Daughtridge said that perception hasn’t materialized in the way he and his colleagues feared. He noted that patients typically don’t feel any different when taking PrEP, causing some to worry whether the drug is working. The urine test can prove that it is.

“The test gives them a piece of mind that they didn’t have before,” Daughtridge said.

The company is currently launching pilot programs with the public health departments in Houston and Washington, DC, to gauge the test’s effect on adherence and also to better understand physician and patient sentiments.

Going forward, Daughtridge said, the company is also working to develop a point-of-care test that could give same-day in-clinic results, as well as a smartphone scanner that would allow a patient to take the test at home and upload a scan of the test strip directly into their electronic health record.

Daughtridge said a goal of the urine test is to be affordable and easy to use so that it doesn’t add additional inconvenience or expense for patients already on the high-cost PrEP treatment. He noted that many patients are adherent in the period immediately after they are initially prescribed PrEP but then become less adherent as time goes on. He hopes UrSure’s tests will make it more feasible to track and improve adherence over the long term.

“It’s probably even more valuable the further you go along on the medication,” Daughtridge said.