Theme: Epidemiology & Public Health Research Year: 2024
Background: Sustained virologic response at 12-weeks post-treatment completion (SVR12) is considered the gold standard clinical efficacy endpoint for Direct Acting Antiviral (DAA) hepatitis C (HCV) treatment. However, its origin dates back to interferon therapy which required close clinical observation and had cure rates closer to 60%, compared to DAA’s 90-95%. While serology from the SVR12 timepoint consistently predicts cure, it also requires patients to return for bloodwork three months after they complete treatment. This gap in time may contribute to loss to follow up, especially for those who often face instability in their life, such as people who inject drugs.
Methods: In an attempt to assess opportunities to tailor care to the needs these patients, we assessed concordance between the presence of HCV RNA in serum samples at end of treatment, 4-weeks post-treatment (SVR4), and SVR12 “cure” by calculating positive predictive values (PPV) and negative predictive values (NPV). Clinical data was used from a clinical trial (NCT03987503) of participants who received a standard 12 week course of the DAA sofosbuvir/velpatasvir (SOF/VEL).
Results: Of the eighty-seven (N=87) participants who initiated treatment in the trial, 71% were male, 97% had an income below the national poverty line, 80% had injected drugs in the past 3 months, and 43% were living outdoors or in a vehicle. Sixty-nine (79%) completed treatment and fifty-eight attained SVR12 or cure. Six participants were loss to follow-up between end of treatment and SVR12. Both the PPV and NPV of SVR4 for SVR12 were 100%. The PPV and NPV of end of treatment for SVR12 was 96% and 100%, respectively. Those with discordance between end of treatment and SVR12 (n=2) had different genotypes pre- and post-treatment, likely indicating new (re)infection.
Conclusion: Our analysis shows that among this cohort, serologic testing from end of treatment and SVR4 closely aligned with those at SVR12. Additionally, fewer participants were loss to follow-up at these timepoints which may strengthen the precision of HCV treatment outcome data. Broader DAA clinical trial data should be analyzed to assess if earlier timepoints consistently predict HCV cure outside of this cohort.
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