Patient population
From August of 2016 through March of 2017, 117 patients were treated at 18 study sites in Japan. The median age for the study population was 64 years (range 21–81) (Table 1). Thirty-three percent (39/117) of patients had cirrhosis. Fifty-seven percent (67/117) had a non-CC IL-28B genotype. Among patients with genotype 1 infection, 97% (92/95) had subtype 1b. Most patients (84%, 83/117) had undergone 2 or more prior DAA treatment regimens. The median (range) reported duration of the most recent prior DAA treatment was 14 (7–36) weeks in the 12-week group and 12 (6–36) in the 24-week group. Seventy-five percent (88/117) of patients were previously treated with both NS5A and NS3/4 inhibitors, including 8 patients who had also been treated with NS5B inhibitor. Among patients with genotype 1 HCV infection, the most common prior treatment regimen was daclatasvir plus asunaprevir (86%, 82/95), and, among patients with genotype 2 HCV infection, the most common prior DAA was sofosbuvir (91%, 20/22). Ninety-five percent of patients (110/116) had 1 or more NS5A RASs at baseline, including 71% (82/116) with 2 or more NS5A RASs. Of the 117 patients who were enrolled, 114 (97%) completed treatment (Fig. 1).
Table 1 Patient demographics and baseline characteristics
Efficacy
Overall, SVR12 rates were higher with 24 weeks versus 12 weeks of treatment (Table 2). In the 12- and 24-week treatment groups, 82% (47/57; 95% CI 70–91%) and 97% (58/60; 95% CI 88–100%) of patients achieved SVR12, respectively. Among patients with HCV genotype 1, SVR12 rates were 85% (40/47; 95% CI 72–94%) with 12 weeks and 98% (47/48; 95% CI 89–100%) with 24 weeks. The SVR12 rates of sofosbuvir–velpatasvir plus ribavirin for 12 weeks (p < 0.001) and 24 weeks (p < 0.001) in HCV genotype 1 patients were both statistically superior to the historical control rate of 50%. For patients with HCV genotype 2, SVR12 rates were 70% (7/10; 95% CI 35–93%) for 12 weeks and 92% (11/12; 95% CI 62–100%) for 24 weeks. Comparatively, the difference in SVR12 rate for the treatment groups overall was statistically significant (24 weeks compared with 12 weeks for all patients, p = 0.023); however, the differences in the SVR12 rates by genotype for the treatment groups were not statistically significant (for patients with genotype 1, p = 0.0548; for patients with genotype 2, p = 0.4511).
Table 2 Treatment response to sofosbuvir-velpatasvir + ribavirin Results were similar between patients with and without cirrhosis in both treatment groups (Table 3). In the 12 week group, SVR12 rates were 82% (32/39) for those without cirrhosis and 83% (15/18) for those with compensated cirrhosis. In the 24-week group, they were 95% (37/39) in patients without cirrhosis and 100% (21/21) in those with cirrhosis.
Table 3 SVR12 by cirrhosis, prior direct-acting antivirals, and baseline resistance-associated substitutions
The SVR12 rates for patients with genotype 1 HCV infection previously treated with both NS5A and NS3/4 inhibitors, including those who had also used NS5B inhibitor, were 86% (38/44) and 98% (40/41) in the 12- and 24-week groups, respectively. SVR12 rates were 86% (36/42) and 98% (39/40) with 12 and 24 weeks of treatment, respectively, in patients previously treated with daclatasvir plus asunaprevir, 100% (3/3) and 100% (11/11) in those previously treated with ledipasvir–sofosbuvir, and 100% (1/1) and 100% (4/4) in patients previously treated with daclatasvir plus asunaprevir and then ledipasvir–sofosbuvir. The SVR12 rates in the 12- and 24-week groups for patients with genotype 2 HCV infection previously treated with sofosbuvir were 67% (6/9) and 91% (10/11), respectively.
No patients had virologic nonresponse. A total of 11 patients relapsed, 9 of whom were in the 12-week grosup. One patient terminated treatment on day 8 because of an adverse event and did not achieve SVR12. In post hoc logistic regression analyses of relapse in the overall population (n = 116), the only factor that was statistically significant was treatment duration, where the likelihood for relapse was 5.5-fold higher with 12 weeks than with 24 weeks (p = 0.0399). For genotype 1 patients in both treatment groups (n = 95) and in the 12 week group alone (n = 47), no factor was statistically significant.
Viral resistance analyses
Among the 116 patients included in the resistance analysis population, the prevalence of baseline NS5A RASs was high and similar between the two treatment groups irrespective of genotype. Overall, 96% (54/56) in the 12-week group and 93% (56/60) in the 24-week group had baseline NS5A RASs. Most patients with genotype 1 HCV had 2 or more NS5A RASs (overall 85%, 80/94), including Y93 alone or in combination with other substitutions (overall 85%, 80/94) and P32 deletions (overall 5%, 5/94). The majority of those with a Y93 RAS also had L31 RAS (overall 89%, 71/80). Eighty-six percent (71/80) of patients with genotype 2 infection had 1 or 2 NS5A RASs at baseline (overall 86%, 19/22; genotype 2a 87%, 13/15; genotype 2b 86%, 6/7). All patients with genotype 2 infection and NS5A RAVs had L31M.
SVR12 was achieved in 85% (46/54) and 96% (54/56) of patients with baseline NS5A RASs in the 12- and 24-week groups, respectively (Table 3). Among those with two or more baseline NS5A RASs, 85% (34/40) in the 12-week group and 98% (41/42) in the 24-week group achieved SVR12. For patients with HCV genotype 1, SVR12 was achieved in 85% (35/41) and 100% (39/39) of those with any Y93 RAS, 82% (28/34) and 100% (37/37) for those with Y93 combined with L31 RASs, and 100% (2/2) and 67% (2/3) in patients with P32 deletions, in the 12- and 24-week groups, respectively. Among patients with genotype 2 infection with L31M RASs, 78% (7/9) and 90% (9/10) achieved SVR12 in the 12- and 24-week groups, respectively.
Seven patients (n = 4 HCV genotype 1b infection, n = 3 HCV genotype 2b infection) had NS5B RASs at baseline (n = 3 in the 12-week group and n = 4 in the 24-week group). All achieved SVR12.
None of the 11 patients who relapsed across the treatment groups developed treatment-emergent RASs at a cutoff of 15% or 1%.
Safety
Eighty-one percent (46/57) of patients in the 12-week group and 75% (45/60) of patients in the 24-week group experienced an adverse event (Table 4). The most commonly reported adverse events were viral upper respiratory tract infection (28%), anemia (23%), and headache (11%). Anemia was reported at similar percentages in the 12- and 24-week treatment groups, 25% and 22%, respectively. Four patients, all in the 24-week group, experienced a Grade 3, serious adverse event; 2 had hepatocellular carcinoma, 1 had hepatic angiosarcoma, and 1 had pneumonia. None of the serious adverse events was considered related to study treatment.
Table 4 Adverse events and laboratory abnormalities Three patients had adverse events leading to premature discontinuation of treatment. One of them, in the 12-week group, discontinued on treatment day 8 because of rash and did not achieve SVR12. The rash was considered related to study treatment and resolved within 1 month. Another patient, in the 24-week group, had hepatic angiosarcoma that was considered unrelated to study treatment. This patient discontinued study drugs on day 97 of treatment and achieved SVR12. The third patient, also in the 24-week group, experienced moderately severe depression that was considered related to study treatment; the patient’s medical history was notable for a prior episode of depression related to treatment with peginterferon plus ribavirin. This patient discontinued after 5 weeks of treatment and achieved SVR12.
Ten patients had adverse events that led to ribavirin dose reduction (n = 9) or interruption (n = 1). All ten patients had anemia that was considered related to study treatment, and one also had headache considered related to study treatment. Seven of the ten reached SVR12; three experienced relapse. All three had genotype 2 HCV and were in the 12-week group.
No patients had Grade 4 laboratory abnormalities. The only Grade 3 laboratory abnormalities that occurred in more than one patient were hyperglycemia (n = 8), lymphocyte reduction (n = 8), and decreased hemoglobin levels (n = 6). All eight patients with Grade 3 hyperglycemia had a history of diabetes.