1 INTRODUCTION

Chronic hepatitis C virus (HCV) infection is the main cause of liver pathologies and hepatocellular carcinoma (HCC) worldwide.¹ Globally, 71 million people infected with chronic hepatitis C (CHC) infection, with an estimated 3.5 to 5 million death annually.² According to recent estimates, Pakistan has the second-largest HCV burden in the world, with 4.5% to 8.2% HCV seroprevalence.^{3, 4} Out of the seven major HCV genotypes,⁵ the majority of HCV infections in Pakistan are GT3a (69.1%), followed by GT1 (7.1%), GT2 (4.2%), and GT4 (2.2%).^{4, 6} In Pakistan, HCV is transmitted by many risk factors, such as health care practices, that is injections and blood transfusion in health care professionals (27%-42.3%) and in the general population (7.8%-68%), community-based activities, that is ear and nose piercing, barbering, and injecting drug use.^{4, 7, 8}

Before the introduction of direct-acting antivirals (DAAs), the HCV treatment was interferon (IFN)-based that had many side effects, that is poorly tolerated and low sustained virological response (SVR) rate (50%).⁹ In spite of “Chief Minister's Program for Hepatitis B and C Control in Pakistan,” the IFN-based treatment was only effective in 67% to 74% of the infected population.^{10, 11}

Hepatitis C treatment has been transformed by the development of DAAs. HCV replication cycle is inhibited by these drugs mainly interfering with the activity of nonstructural proteins of HCV.¹² Three drug classes (inhibitors of the NS3/NS4A protease, inhibitors of the NS5A complex, and inhibitors of the NS5B polymerase) have been developed and approved by the FDA. Combinations of two or more drugs from three classes achieve high (>90%) SVR rates and are well tolerated.¹²

In Pakistan, the treatment for CHC infection is changing to the new DAAs. Since November 2014, sofosbuvir and ribavirin were the registered and widely available DAAs in Pakistan.^{13, 14} Sofosbuvir (SOF) inhibits the NS5B region of HCV which encodes RNA-dependent RNA polymerase enzyme for viral replication. SOF has pangenotypic action with less side effects as compared with IFN-based therapy.¹⁵ Pakistan is among the high-burden countries for HCV where the majority of the HCV-infected population fall in the lower-income category. They are unable to buy high priced branded SOF for their treatment. Therefore, the government of Pakistan and the pharmaceutical companies started manufacturing SOF generics at low prices to control the HCV prevalence.¹⁶

The inclusion of SOF-based DAAs in the “National Guidelines for HCV Treatment in Pakistan” has increased its use by clinicians. Recently, daclatasvir (DCV; HCV NS5A replication complex inhibitor) the new DAAs are also available in Pakistan and added in the national treatment program with a combination of SOF against GT3. Such additions will certainly offer a better safety profile with improving patient compliance to treatment.^{15, 17}

However, these DAAs are designed on the basis of the structure of the protein of GT1HCV. Also, the registration trials for these drugs contained few patients infected with GT3HCV, which is highly prevalent in Pakistan. This raises a concern about the effectiveness of these drugs on Pakistani patients. Given the limited data on treatment of chronic GT3 HCV infection with DAAs and the above concerns, this study was conducted to gather data on the antiviral efficacy of generic DAAs with respect to treatment outcome in chronic HCV Pakistani patients. The predictors of SVR at 12 weeks and the safety profile of DAAs were also determined in this cohort.

2 MATERIALS AND METHODS

2.2 Medications

Treatment and management of patients at study centers were as per the national guidelines. Generic SOF was given in a dose of 400 mg/day, DCV in a dose of 60 mg/day, both in a single daily dose and patients were advised to take them after breakfast for 12 weeks. Ribavirin 1000 mg (in patients < 75 kg) or 1200 mg (in patients >75 kg) was added to the regimen (Figure 1).

3 RESULTS

4 DISCUSSION

Development of DAA agents is the landmark in the treatment of HCV infection. This IFN-free treatment provides high SVR rates and tends to prevent liver disease progression. The availability of DAA regimens replaced IFN treatment for HCV therapy across the globe.¹² A notable decline was observed in the prices of DAAs by the DAAs generics availability in 101 developing countries,²⁰ but the scientific assessment is required for the efficacy of these generics. However, to design and to implement strategies regarding the treatment of HCV on a large scale, it is necessary to review the existing experience with DAAs in Pakistani population.

We report here a real-world experience with generic DCV and SOF with or without RBV as combination therapy and SOF with RBV as monotherapy for treating the patient with HCV-GT3. This is one of the largest reports presenting real-life data using this combination in treating HCV-GT3 patients from Pakistan. More than 90% of patients in Pakistan are infected with HCV-GT3,⁶ therefore, subgenotyping was not performed at baseline, thus this report is taken to represent results of HCV-GT3 treatment. DCV and SOF with or without RBV is recommended by both US treatment guidelines and European guidelines against HCV-GT3 irrespective of HCV treatment experience or cirrhosis status and subgenotype.²¹

In this study, the overall clinical effectiveness (SVR12) of DCV + SOF ( ± RBV) treatment was 98% (98.8% without RBV and 90.2% with RBV). These findings are comparable with the Indian study where SVR12 rate was 96% in GT3.²² Likewise, also, these results are aligned with ALLY-3+ studies where ≥96% SVR12 rates achieved in GT3 patients.²³ This response rate is in agreement with the results of Sulkowski et al²⁴ where HCV-GT1, 2 and 3 achieved 89% to 98% SVR12 rate depending on the genotype. Another large cohort of Egypt with GT4 was analyzed by Omar et al²⁵ with 95.1% SVR12 rate (95.4% without RBV and 94.7% with RBV). Belperio et al²⁶ reported SVR12 rate in GT2 (94.5% without RBV and 88.1% with RBV) and GT3 (90.8% without RBV and 88.1% with RBV). In comparison to our response rate, similar findings are reported in other studies.^{22, 27-30} These results supported that the chance of achieving a cure was higher with DCV + SOF then the DCV + SOF + RBV. It shows the use of RBV did not improve the SVR rate. Moreover, a study reported that RBV should be avoided due to its associated adverse effects and anemia.³¹

In our study, the regimen DCV and SOF found to be superior to the previous standard of care SOF and RBV that shows lower SVR12 (75%) in the treatment of CHC GT3. This is in agreement with the results of the study conducted by del Rio-Valencia et al³⁰ where the response rate was 75% and Jacobson et al³² where they reported 78% SVR12. This indicates that only SOF is less effective than other combinational therapies. Thus, a longer period of therapy is required to remove remaining viral reservoirs or the addition of other DAAs to the treatment.

For HCV patients with GT3, prior treatment experience and advanced liver disease are found to be significant predictors of SVR rate in multiple studies. In the current study, treatment-naive patients treated with DCV + SOF achieved higher SVR12 (99%) as compared with pretreated patients (90%) of GT3. This is in line with the results published by Nelson et al²⁸ where SVR12 rates were 90% in treatment-naive and 86% in pretreated patients and SVR12 was 84% and 80% in treatment-naive and pretreated patients, respectively, in a study by Umar et al.³³ Similarly, in our study, cirrhotic patients treated with DCV + SOF achieved (92% SVR12) as compared with non-cirrhotic patients (98% SVR12). In compliance with our study findings, SVR12 rates greater than 90% in cirrhotic patients was reported in respective studies conducted elsewhere.^{22, 27-29, 31, 34} The present data indicate that DCV + SOF achieved high SVR rates even among cirrhotic patients irrespective of RBV use.

Cure rates above 90% have been reported using different combinations of all-oral DAAs in CHC patients treated in several clinical trials.^{35, 36} Initial real-world results support these findings, but the efficacy tends to be lower mainly due to predictors of lower SVR rate in registration trials. Furthermore, doctor's limited expertise using these new DAAs led to the impairment of their success.^35-42 Given the high SVR rates with DAAs, treatment failure studies are comparatively low and largely influenced by treatment strategies explored and drug combinations.^{41, 43, 44} Furthermore, predictors of SVR rates are not uniform in different trials making it difficult to make comparisons. Baseline variables associated with a lower SVR rate includes the presence of natural polymorphisms at the viral nonstructural genes that reduce drug susceptibility, infection with HCV GT1 and GT3, liver cirrhosis, prior treatment experience, and elevated viral load.^{5, 43, 44}

In our multivariate models, significant predictors of SVR12 were patients’ education status, treatment regimen, viral load, and ALT. Educated patients achieved a higher rate of SVR12 as compared with uneducated patients. During therapy, uneducated people with an incomplete profile (n = 198) were excluded from the study due to the premature drug cessation. However, among the included study participants, 13 of 20 treatment failure cases were uneducated due to recurrent missing doses. In agreement with our results, various studies reported that higher education level is associated with better compliance and treatment outcomes.^45-48

In our study, those patients who were treated with DCV + SOF significantly achieved higher SVR12 (P = .011) than those who were treated with other treatments like DCV + SOF + RBV and SOF + RBV. These findings are in alliance with the results of a study by Welzel et al.²⁹ Patients with viral load <800.000 IU/mL significantly achieved higher SVR12 (P = .022) than viral load ≥800.000 IU/mL. These findings are comparable with the results of a Brazilian study¹⁸ and Lourianne study.¹⁵ In our study, the negative predictor of SVR12 was elevated ALT level. Those patients who had elevated ALT levels were less likely to achieve higher SVR12 (P = .013). Our findings are supported by a study conducted by Huynh et al⁴⁹ where ALT levels were associated with SVR rate. In another study, the authors reported that ALT can serve as a potential biochemical marker for HCV treatment response.⁵⁰ A study conducted by Khan et al⁵¹ reported that baseline ALT level was significantly associated with SVR rate in multivariate analysis.

As the treatment with generic DAAs is a safe and effective alternative toward the elimination of HCV,⁵² the safety profile of these generic DAAs in our study was well tolerated. The most common AEs were skin rash, insomnia, oral ulcers, and fatigue which is comparable with study findings conducted by Leroy et al,²³ where fatigue and insomnia were major side effects. In our study apart from these major AEs, the patient also complained of skin rash (43.8%) and oral ulcers (30.2%). A study from Egypt reported a skin rash up to 9.8% of the patients using generic sofosbuvir and daclatasvir.²⁰ Oral ulcers have been found 8.8% with this combination in Pakistani population.³³

5 CONCLUSIONS

The findings of the current study confirmed that second-generation generic DAAs (sofosbuvir with daclatasvir) are highly effective for CHC patient's treatment in Pakistan, particularly for genotype 3. Current SVR rates with sofosbuvir-based DAAs were higher as compared with previous therapies. Host factors like education level, treatment strategy, viral load, and ALT were seemed to be the predictors of SVR rate. The safety profile of these DAAs was well tolerated and safe. A large multicenter prospective study is recommended to confirm the present findings.

6 STUDY LIMITATIONS

This study was limited to only 3 months follow-up. A multicenter study with a longer follow-up of 6 months is recommended. Furthermore, only host factors being assessed in this study, the viral factors (resistance-associated substitutions) need to be assessed for the efficacy of the therapeutic regimens.

AUTHOR CONTRIBUTIONS

All authors (SM, AM, MU, AK, SS, and SM) made substantial contributions to the conception and design of this study. SM and AK made substantial contributions to the acquisition and analysis of the data. SM drafted the manuscript and AM, MU, SS, and SM were involved in critical revision for important intellectual content. All authors read and approved the final manuscript. Study is supervised by SM.

ETHICS STATEMENT

The study was approved by the ethical review board of Rawalpindi Medical University, Holy family, Institute of Biomedical and Genetic Engineering and National University of Science and Technology (IRB-130). All procedures performed in studies involving human participants were in accordance with the ethical standards of the institutional and/or national research committee and with the 1964 Helsinki declaration and its later amendments or comparable ethical standards.