Evaluation of therapeutic efficacy of ifn treatments in hcv infected svr and non-svr patients

Abstract

Hepatitis C Virus (HCV) causes one of the most lethal kinds of infections of the liver. Nearly 200 million all over the world are infected with this virus making it a major health burden. During chronic infection, HCV leads to liver cirrhosis in 70% of the cases and can also cause hepatocellular carcinoma which has a mortality rate of 50%. A member of the Flaviviridae family, HCV has eluded researchers for a long time due to its highly mutative nature which makes it difficult to design effective antiviral strategies and vaccines against this major menace. There is no systematic national level survey or monitoring strategy for HCV infection. Therefore one has to rely on small scale studies conducted from different regions of Pakistan. Prevalence data that focuses on underdeveloped urban and remote rural areas of Pakistan is severely lacking. Therefore, the present study has been conducted in the rural side of Sindh to estimate the spread of HCV. The study screened 31560 individuals from different areas of Gambat in interior Sindh, from July 2010 to March 2015 at Atta-ur-Rehman School of Applied Biosciences (ASAB), in collaboration with Gambat Institute of Medical Sciences. The participants were asked about their exposure to numerous potential risk factors of HCV and later tested by ELISA (Enzyme-linked Immunosorbant Assay) and RT-PCR to confirm the presence of HCV infection. Clinicopathological data, like viral RNA load, HCV genotype, ALT (Alanine-aminotransferase), RBC (Red blood cell), WBC (White blood cell), platelet and hemoglobin levels in HCV positive cases was determined before, during and after the completion of therapy. Later, treatment response was assessed based on different combinations of therapy which included both standard regimens of pegInterferon-α+Ribavirin and newly approved drugs. To the best of our knowledge, this study is the first of its kind that has assessed the efficacy of ___________________________________________________________________Abstract 2 Sofosbuvir therapy, a NS5B RNA dependent RNA Polymerase inhibitor, in HCV infected population in Pakistan. Furthermore, the current study also analyzed the rate of mutations in the ISDR (Interferon sensitivity determining region), PKRBD (Protein Kinase R binding domain) and ex-PKRBD regions of the NS5A gene of HCV. After confirmation with RT-PCR, 4314 individuals were found positive for HCV viremia, implying a prevalence of 13.7%. The frequency of HCV antibodies was higher in males (14.98%) than in female (11.74%), moreover the age group of 41-50 years had the highest number of HCV infections. It was observed that multiple risk factors were strongly associated with HCV infection, like use/reuse of syringes and sexual contact. As compared to other genotypes; genotypes 3a was the most prevalent genotype in our study group, accounting for 70% of the sample. Overall Sustained Virologic Response (SVR) was observed in 924 (72.65%) patients with the pegInterferon-α+Ribavirin therapy.It was observed that pegInterferon-α+Ribavirin therapy was less efficacious, SVR 70%, compared to sofosbuvir+pegInterferon-α+Ribavirin therapy which achieved SVR of 97%. Overall treatment response was better in genotype 2 or 3 compared with genotype 1 or 4. It was further concluded that viral load during the course of therapy and significant association with the outcome of treatment. In the patients who showed sustained response to therapy, the changes in ALT levels were associated with the therapy outcome whereas in non-responders no such correlation with ALT levels was observed. While this study did not observe WBC, RBC and hemoglobin levels to be correlated with treatment response, platelet count was a significant factor in determining sustained response to therapy. We found that platelet count < 140000/L showed less response to therapy whereas platelet count ≥ 140000/L signified better treatment outcome. ___________________________________________________________________Abstract 3 A 579 bp fragment from NS5A gene was sequenced from some SVR and NR patients of HCV genotype 3a. The number of mutations in the non-responders was found greater in the ISDR than the responders, whereas, in the PKRBD region the number of mutations was higher in SVR group compared to the non-SVR. With each region, the number of mutations had significant correlation with the outcome of treatment. Moreover, specific amino acid substitutions were also found outside the PKRBD region. In summation, the present study brings to light the extremely high rate of active HCV infection in the interior Sindh region. This finding highlights that most of the studies on urban population underestimate the real rate of HCV prevalence in Pakistan. The likely possibility of HCV transmission via sexual contact has also been reported in this study where the sexual route has been considered an inefficient mode of transmission in past studies. Additionally the efficacy of the newly approved sofosbuvir therapy in achieving higher sustained response rates has been demonstrated which leads to the possibility of further studies that explore its potential in the more resistant genotypes like, genotype 1b. Additionally we found that number of mutations in ISDR and PKRBD regions of NS5A were associated to some level with response to treatment. Together all these findings will contribute to forming better awareness, management and treatment strategies for HCV infection.