New Test Can Assist in Fight Against HIV

A new test that can effectively estimate HIV-negative patients’ adherence to prescribed drugs to prevent the transmission of human immunodeficiency virus (HIV) during sexual intercourse has been discovered by researchers at the Skaggs School of Pharmacy and Pharmaceutical Sciences at CU Anschutz, according to a press release.

HIV attacks the body’s immune system, and if left untreated, the virus can develop into AIDS. The virus remains a major global health threat in that an estimated 1.2 million individuals, over 13 years of age, living in the United States alone are HIV-positive, including 156,300 individuals who had not been diagnosed, according to the Centers for Disease Control and Prevention (CDC). There is no cure for HIV, and once an individual becomes infected with the virus, he/she will have it for life. However, it can be controlled through antiretroviral therapy (ART).

As with most treatment plans though, the effectiveness depends on patients’ adherence to the treatment regimens. According to an article on the challenge of patient adherence, study authors write, “Patient nonadherence can be a pervasive threat to health and wellbeing and carry on appreciable economic burden as well. In some disease conditions, more than 40% of patient sustain significant risks by misunderstanding, forgetting, or ignoring healthcare advice.”

In order to test the amount of pre-exposure prophylactic, or PrEP, medicine a patient used, researchers have created a “blood spot test.” Using just a spot of blood from the patient, it is able to measure the amount of antiretroviral drugs the patient had used. According to the press release, when it comes to HIV prevention, the antiretroviral PrEP drug, Truvada, is the only drug thus far, that has been approved by the Food and Drug Administration (FDA) and it has been proven to be “more than 90 percent effective in stopping HIV transmission during sex-in those who use it consistently.” In fact, on Truvada’s official website, the tag line reads, “TRUVADA for PrEP can help, but only if taken daily. Studies show a strong link between taking TRUVADA for PrEP every day and how well the medicine works.”

This new test provides a way for healthcare officials to see if HIV-negative patients are using Truvada consistently, and thus, are receiving adequate protection from HIV transmission through sexual intercourse.

Pete Anderson, PharmD and professor of pharmaceutical sciences at the CU Skaggs School of Pharmacy, said, “There’s a need to objectively measure PrEP adherence because traditional ways have not been very effective. This assay takes advantage of the long half-life of PrEP medication in red blood cells. This means the drug builds up in these cells only if the patient takes it consistently.”

The method consists of taking a “spot” of blood from the patient and putting it on an “absorbent paper-like card.” The card is then sent out to the lab where researchers are able to isolate and measure the amount of PrEP drugs found in the blood cells. By measuring the amount of the drug in the blood cells, researchers are able to estimate how many doses of the drug taken in the last month or two, according to the press release.

Lane Bushman, lab manager at the CU Skaggs School of Pharmacy who had developed the test, said, “Most cell sample collections require significant effort for processing, but the dried blood spot is an easy sample collection technique. This helps with implementing the test in most settings.”

In the press release, Anderson further stressed the need for a test like this worldwide. He said, “This assay has been in high demand for PrEP studies. We recently helped a South African lab to develop the method to help with testing demand in that region.”

The test is now being used by researchers internationally and the developers feel that it can be applied to measuring patient adherence pertaining to other drugs as well.

When speaking of future research, Anderson said, “We now have a grant to develop a way to do the testing at bedside. We also see applications for other medications. For example, our colleague Dr. Jennifer Kiser is evaluating if a similar test could work for Hepatitis-C medications.”