HCV genotype 4a has been reported as the predominant subtype in Egypt in some studies [18,19,20]. In a study conducted in Damietta, El-Tahan et al. [21] found that HCV genotype 4a represents 93.3% (28/30) and genotype 1 represents 6.7% (2/30). However, we found that all 59 patients were infected with genotype 4a without any baseline RASs at NS34A regions that reflect the high prevalence of HCV genotype 4a in Upper Egypt and the absence of baseline RASs in NS34A regions in Egyptian chronic hepatitis C (CHC) patients, and this is unlike other regions in the world, whereas the prevalence of Q80K in HCV genotype 1 in North America was 34% [9]. To the best of our knowledge, we had conducted the first study that reported the prevalence of baseline NS34A RASs in patients treated with DAAs in routine clinical practice in Upper Egypt.
In the present study, the virological response agrees with the results of another study conducted by El-Khayat et al. [22] who assessed SVR12 for 583 Egyptian patients with HCV genotype 4 infections after receiving SMV/SOF without ribavirin for 12 weeks, and the SVR12 rate in their study was 95.7% and was lower among cirrhotic patients (80.8%). Our results are also consistent with a study conducted by Eletreby et al. [23] who revealed the SVR12 rate achieved among a cohort of 6211 patients with genotype 4 HCV infection was 94%. Besides, we found that patients who achieved SVR12 were still a viremic 72 weeks after EOT.
RAS testing was done in the two patients who did not achieve SVR, and this revealed the presence of Q80K RAS in one patient (50%). Due to the small number of patients who did not achieve SVR12, only two patients, we could not discover the possible predictors of the development of emerging NS34A RASs. We just observed that the female patient who developed Q80K after SMV/SOF therapy had leucopenia at baseline [TLC (Total leucocytic count) = 2.5 K/cm] while the other male patient who did not develop Q80K had normal TLC (4.5 K/cm).
ALT is a biochemical marker for hepatocyte injury. Persistent ALT elevation is associated with chronic hepatitis C progression and increased risk for cirrhosis and an indication for treatment [24]. In the present study, there was a highly significant difference between ALT levels before treatment versus the ALT level after treatment at week 4, week 8, EOT, and 12 weeks after EOT (p value = 0.001). These results agree with De Pace et al. [25] who found that AST and ALT decreased during therapy: baseline mean AST = 52 (32–81) UI/mL and mean ALT = 52.5 (34–83.2) UI/mL vs EOT AST = 21 (18–28) UI/mL and ALT = 17 (13–24.2). These results show the rapid improvement of the inflammatory process and hepatocyte injury accompanying HCV infection.
Also, our study showed that non-invasive biomarkers of liver fibrosis as APRI score and FIB-4 index improved significantly in most of the patients. Unexpectedly, they improved in patients who did not achieve SVR. Also, we found that the possible predictors of APRI score improvement were lower baseline platelet, higher baseline AST, and higher baseline APRI score. In addition, we found that higher baseline AST was a possible predictor of Fib-4 index improvement. These results go in concordance with De Pace et al. [25] who found a significant dropping of APRI score and a moderate improvement in platelet values from baseline to EOT. In our study, platelet count increased significantly after treating patients with SMV/SOF combination therapy, and this agrees with Sayyar et al. [26]. Unexpectedly in our study, PLT count increased even in patients who did not achieve SVR.
Lower baseline platelet count, higher baseline APRI score, Fib-4 index, lower baseline prothrombin, and higher baseline AFP (alfa-fetoprorein) were associated with the increased PLT (platelet) count after treatment. Nevertheless, linear regression analysis showed that lower baseline platelet count is the main predictor of the platelet count increase after treatment. This result may be explained by Amer et al. who studied the relation between platelet viral load and the possible response after antiviral therapy; low baseline platelet count and low platelet viral load may explain the better response in platelet count after antiviral therapy [27].
Amer et al. were investigating platelets as a possible reservoir of HCV and predictor of response to treatment, and they found that the platelet count tended to be lower among those with rapid virological response (RVR) compared to those with non-RVR throughout the follow-up. In addition, they found that among individuals with RVR, platelet counts declined slightly by week 4 and week 12 then gradually increased to reach pre-treatment levels by week 48, but there was no similar decline among patients who did not achieve RVR. Also, they found that platelet count remained almost constant over time, among non-SVR, but among SVR, it should have a steady small decline until week 12, then it started to increase to pre-treatment levels, and also, they found that platelet counts did not correlate with platelet or serum viral loads or treatment responses [27].
Regarding the effect of antiviral therapy on the degree of hepatic fibrosis in our cohort, there was a significant difference between the degree of liver stiffness by fibroscan before and after therapy. According to literatures, a more accurate evaluation of fibrosis regression using fibroscan needs longer duration after EOT. Liver stiffness measurement can be influenced by inflammatory activity. Transient elastography improves within a short period of time following SVR, likely reflecting resolution of inflammation rather than regression of fibrosis. However, for patients evaluated at later time points post-SVR, elastography appears to have good performance characteristics. Thus, delaying the post SVR assessment of liver stiffness for at least 1 year post SVR would seem prudent [28,29,30]. So we decided to choose a point of time which is of longer duration than 1 year for a better and more accurate evaluation of liver fibrosis regression.
Pons et al. [31] reported that the improvement of liver stiffness was found 4 weeks after starting DAAs therapy, which most probably reflects a reduction in inflammation rather than in fibrosis. We found that there was a significant difference between those patients who achieved liver stiffness improvement and those who did not achieve liver stiffness improvement regarding treatment status before treatment and the improvement occurring in the Fib-4 index after treatment. Patients who were naïve or who showed post-treatment Fib-4 improvement were more liable for improvement of LSM after SMV/SOF therapy. These parameters may be possible predictors of liver stiffness improvement.
Tag-Adeen et al. [32], in a study conducted in Qena University Hospital that enrolled 80 CHC patients who received different DAAs regimens, found that LSM dropped from 15.6 ± 10.8 to 12.1 ±8 .7 kPa post-SVR; the maximum change of − 5.8 occurred in F4 versus − 2.79, − 1.28, and + 0.08 in F3, F2, and F0–F1, respectively (p < 0.0001). Also, those patients showed significant improvement in the APRI score and Fib-4 index after achieving SVR. They found that younger age, male gender, raised baseline ALT, and raised AST were possible predictors of LSM improvement. Concerning the safety profile in this cohort, the combination of SOF and SMV appeared to be well tolerated in the majority of patients, where no deaths or serious side effects leading to the stoppage of the therapy had been reported. The incidence and degree of the adverse effects are comparable to those reported in the published international trials using the same regimen and with the same doses.
The safety profile seen in this study is in-line with the OPTIMIST-1 and OPTIMIST-2 studies [33]. Among the fifty-nine patients, minor clinical side effects as fatigue and bleeding gums were reported in one case for each (1.7%). Headache and photosensitivity were reported in 2 patients for each (3.4%). After EOT, all the dermatological manifestations gradually disappeared with a complete resolution with no residual sequels.
Raised bilirubin > 1.2 mg/dl was the most frequent adverse effect where it occurred in 32/59 (54.2%). Total serum bilirubin level exceeded 2 mg/dl in nine patients (9/59) (17.3%). This rise was reversible and the bilirubin level began to improve at week 8 of therapy, improved significantly at EOT, and returned to normal 12 weeks after EOT.
These findings came in agreement with the findings observed by El-Khayat et al. [22]; photosensitivity occurred in 18 patients among 583 patients (3%) and hyperbilirubinemia occurred in 44 patients (7.2%).
The current work had some limitations: (1) the small sample size was one of the drawbacks of the present cohort; (2) although the absence of baseline NS34A RASs is a good indicator of its low prevalence in Egypt, this made it difficult to study the effect of baseline NS34A RASs on the virological response after receiving the NS34A inhibitor-containing regimen (SMV/SOF combination therapy); (3) we could not study the efficacy of SMV/SOF combination therapy on other HCV genotypes because we found that all patients were infected with HCV genotype 4a only, although this is a good indicator of the high prevalence of genotype 4 in Egypt; and (4) another limitation is that our cohort is a Single Center Experience.