Disclosures: Dahari reports no relevant financial disclosures. Etzion reports consulting for Abbvie and Gilead Sciences and receiving lecture fees from Abbvie, Gilead Sciences and MSD. Please see the study for all other authors’ relevant financial disclosures.
April 05, 2022
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These steps may identify patients eligible for shorter DAA therapy

Disclosures: Dahari reports no relevant financial disclosures. Etzion reports consulting for Abbvie and Gilead Sciences and receiving lecture fees from Abbvie, Gilead Sciences and MSD. Please see the study for all other authors’ relevant financial disclosures.
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Measuring hepatitis C virus at baseline and on days 7 and 14 of therapy — and eliminating blood draws on days 2 and 28 — can identify patients who may be eligible for a shorter duration of therapy, according to a study.

Direct-acting antivirals have “revolutionized” the treatment of HCV infection, leading to a cure in most patients, but their cost remains one of the barriers to elimination, according to Harel Dahari, PhD, an associate professor of hepatology in the Loyola University Chicago Stritch School of Medicine, and Ohad Etzion, MD, director of the department of gastroenterology and liver diseases at Soroka University Medical Center in Israel.

hepatitis c virus
Cutting out hepatitis C virus blood draws on days 2 and 28 can successfully identify patients eligible for shorter therapy duration. Source: Adobe Stock.
Harel Dahari

“The goal of our study was to examine whether response-guided therapy based on mathematical modeling of viral kinetics during the first 2 weeks of DAA therapy would enable optimization of the length of treatment on an individualized basis,” Dahari and Etzion told Healio in a joint email.

They said being able to shorten therapy duration in carefully selected patients would lead to substantial cost savings in HCV management. These patients may include people who inject drugs (PWID), who experience suboptimal adherence to therapy, and pregnant women.

Dahari and Etzion used a model that was based on an analysis of individual kinetic patterns of viral decline obtained from blood samples taken at baseline, day 2, week 1, week 2 and week 4 after initiation of DAA treatment.

Ohad Etzion

According to the researchers, for each patient, calculation of time to cure based on the mathematical model was done after the week 4 blood draw, and according to the model’s estimation, patients were instructed to either continue therapy according to standard of care or to shorten therapy as determined by the model. They then reanalyzed the results to determine whether omitting specific time points of viral load determination would be possible.

According to the study, the first confirmed time-to-cure for each of the 10 patients agreed with the reported estimated time-to-cure. In two of the 10 patients, HCV was detected at day 28 and was used for predicting time-to-cure. The researchers found that excluding day 28 in these two patients had “a limited effect” on time-to-cure projections, which led to underprediction by 2 days in one patient and overprediction by 6 days in the other.

Similarly, they determined that excluding the day 2 HCV measurement also had a limited effect on maximum time-to-cure projections, which they said remained accurate in eight of the 10 cases.

The study demonstrated that excluding day 7 disproportionality affected the maximum time-to-cure projections, resulting in skewed predictions by at least 1 week in six study participants and overprediction by nearly 5 weeks in two additional patients

Based on these findings, the researchers said omitting day 2 and week 4 blood draws did not significantly alter the accuracy of the model for determining expected time-to-cure.

“Treatment of HCV infection does not mandate a fixed duration in all patients. Treatment length can be individualized by utilizing a simple mathematical model for prediction of time-to-cure in a response guided approach,” Dahari and Etzion said. “Implementation of the approach on a larger scale could lead to significant cost saving and optimize therapy duration in specialized population such as PWID and pregnant women.”