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Title: Mutation Analysis of Resistance Associated Variants in Chronic Hepatitis C Patients using Direct Acting Antivirals
Authors: , Abdul Majid
Keywords: Biological & Medical Sciences
Issue Date: 2022
Publisher: University of Peshawar, Peshawar.
Abstract: Recently the use of direct-acting antivirals (DAA’s) for the treatment of both treatment naïve (patients with no previous record of HCV treatment) and treatment-experienced (patients previously treated with conventional interferon/PEG-interferon in combination with or without ribavirin) patients has shown outstanding response. Various studies have reported excellent sustain virologic response among such patients to DAA’s in 85% to 99% population. On the other hand, approximately among 16%± number of patients, treatment failure to DAA’s have also been observed. Maybe these treatment failures are connected to the existence of resistant viral variants in the population. These resistant variants are the products of mutations in amino acids in the viral target protein; such resistant viral variants may lead to compromise the efficacy of various DAA’s therapies. The presence of resistance-associated variants among HCV-infected populations is due to the high genomic diversity of the virus. The present study was designed to evaluate the treatment response of Sofosbuvir and Ribavirin in Chronic Hepatitis C Virus (HCV) patients, and detailed analysis of patients failed to attain sustain virologic response/resistance-associated variants (RAVs). Ethical agreement for the current study was taken from Institutional Review Board, Peshawar Medical College, Peshawar. A total of 270 chronic HCV infected patients visiting Prime Teaching Hospital, Peshawar with HCV genotype 1a, 2a, and 3a both treatment naïve (those patients who had never been through any treatment for HCV) and treatment-experienced (those patients who have already gone through Interferon therapy but failed to treatment) were included in this research project. Patients infected with HCV genotype 1a and 2a received sofosbuvir in combination with ribavirin for 12 weeks and patients infected with HCV genotype 3a for 24 weeks. Blood samples of all enrolled patients were collected before the start of treatment (for HCV RNA detection xiii and genotyping through multiplex PCR) and after completion of therapy for detection of HCV RNA and HCV NS5B gene sequencing (Sanger Method). The RNA samples (collected before the start of treatment and collected after completion of treatment) of those patients who failed to achieve end treatment response(ETR)/sustain virologic response after 24 weeks of treatment (SVR24) were amplified and sequenced to compare both sequences in search for possible resistance-associated mutations. HCV RNA presence in serum was used as a marker for ETR and SVR24 in each case. The primary end point was a sustained virologic response at 24 weeks after the end of treatment. A total of 256 HCV patients were treated; among these, 145(56.64%) were treatment naïve, 111(43.36%) were treatment-experienced, and 24(9.38%) had liver cirrhosis. The standard for a sustained virologic response in treatment-experienced patients was obtained among 135 out 145 patients (93.10%; 95% confidence interval (CI), 88 to 98), amongst treatment-experienced patients in 94 out of 111 patients (84.68%; 95% CI, 78 to 92). Among patients with cirrhotic liver, 31.81% were not responding to treatment, while 46.66% relapsed. In patients with HCV genotype 3a infection, response rates were 91.17%, genotype 2a 100%, and 80.85% among genotype 1a. From the blood samples obtained before the start of the treatment, the HCV NS5B gene of the patients who failed to achieve ETR/SVR24 was sequenced through Sanger Method baseline mutations such as S282T 10/27(37.03%), V321A 07(25.92%), L159F 05(18.51%) and N142T 03(11.11%) were reported in this study. HCV NS5B gene from the blood of RAV’s collected after treatment was again sequenced, and novel mutation such as F145S 05/27(18.51%), R250G 08/27(29.62%), R259L 06/27(22.22%), G556A 09/27(33.33%) and I119S 04/27(14.81%) was reported by this study. Randomly 37 samples were selected for sequencing from the patients who achieved good ETR and xiv SVR24 where none of the patient were detected with substitution. The most common adverse events experienced by the study population during SOF+RBV therapy were fatigue, restlessness, nausea, headache, diarrhea, and burning body sensations. It can be concluded from the results of the present study that Sofosbuvir(DAA) therapy in combination with Ribavirin is the best choice for both treatment naïve and treatment experienced chronic HCV patients in Pakistan. However, patients who failed to achieve sustained virologic response and various baseline/novel substitutions reported in the current study are alarming. These mutations need further detailed analysis, whether such substitutions are responsible for DAA’s resistance in HCV patients. We must not stop here because DAA’s may face the same destiny in time to come like earlier remedies. Keywords: HCV, DAA’s, Sofosbuvir, Ribavirin, NS5B
Gov't Doc #: 25700
Appears in Collections:PhD Thesis of All Public / Private Sector Universities / DAIs.

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