Efficacy of shorter duration HCV treatment in injection drug users (IDUs)

Purpose of the study

The standard duration of HCV treatment is 24–48 weeks, based on the genotype. New Canadian guidelines allow for a shorter duration to be considered, especially in the absence of predictors of a poor response and in the presence of a rapid virologic response (RVR). With this in mind, we have compared the efficacy of shorter vs. standard duration of HCV treatment in IDUs enrolled in an observational modified directly observed therapy (DOT) inner city cohort.

Methods

All HCV-infected patients enrolled in the Pender Community Health Center HCV program were considered for enrolment in this study. Patients eligible for treatment according to contemporary Provincial guidelines were initiated on weekly pegylated interferon along with ribavirin 800–1200 mg/day (according to weight/genotype) with the interferon administered as DOT and the ribavirin dispensed weekly. Adherence and toxicity were monitored weekly, while efficacy was monitored by measurement of HCV-RNA at weeks 4, 12, at end of treatment (ETR), and 6 months later (to document a sustained virologic response, SVR). Patients completing the standard course of treatment constituted the control group, while those discontinuing early due to toxicity or other factors were the non-randomized experimental group, with SVR documented 6 months after the actual termination of therapy.

Summary of results

Among the 32 patients who received treatment (27 males, 20 geno 2/3), 19 (59%) achieved SVR (16 male, 15 geno 2/3), 14/32 received standard and 18/32 received shorter course of therapy. In the latter group, success rate was 8/18 (44%) and was higher in those with genotype 2/3 (6/9 vs. 2/9 for geno 1); 3/4 who had RVR achieved SVR and 4/4 who had no RVR did not achieve SVR. In contrast, in those completing a standard course of therapy, success rate was 9/14 (64%) and was comparable in geno 2/3 (9/11) vs. geno 1 (2/3). The median duration of therapy in the short course group was 15.5 weeks (range 1–6). The main reasons for early discontinuation were toxicity (eight), lack of virologic response (five), addiction-related issues (five).

Conclusion

Shorter duration of treatment of HCV can be successful in IDUs, particularly if the infection is with HCV genotype 2/3 and an RVR can be documented. Although the shorter duration of therapy cannot yet be recommended as a standard of care, these data may help inform therapeutic decisions in the face of inevitable premature discontinuation of therapy.