Hepatitis C genotype 6: A concise review and response-guided therapy proposal

Table 1 Prevalence of hepatitis C virus genotype 6 in Asia

Country of origin	Population	Genotyping method	Prevalence of HCV genotype 6	Author
Thailand	n = 236; Blood donors throughout the country	Reverse hybridization	18.0%	Kanisanon et al[7]
	n = 58; Volunteers from four hospitals located in the North, North-east, South and Center of the country	Core sequencing	8.9%	Sunanchaikarn et al[8]
	n = 126; Blood donors in the Northern Thailand	Core sequencing	31.0%	Jutavigittum et al[9]
	n = 375; Blood donors in the Central Thailand	Core and NS5B sequencing	18.9%	Akkarathamrongsin et al[10]
	n = 40; Immigrant workers from Cambodia (n = 25) and Myanmar (n = 15) in Thailand	Core and NS5B sequencing	56% among Cambodian workers and 26.7% among Myanmar workers	Akkarathamrongsin et al[23]
Myanmar	n = 110; Blood donors in Yangon and its suburbs	NS5B sequencing	20.9%	Shinji et al[11]
	n = 145; Volunteers from four different border cities of Myanmar	Core sequencing	49% (Genotype 6 was mostly found in the Northern cities)	Lwin et al[12]
Vietnam	n = 308; Patients from urban community-based GI practice in Southern Vietnam	Core sequencing	31.5%	Nguyen et al[13]
	n = 135; Blood donors in Hanoi (Northern Vietnam	Core (n = 70) and NS5B (n = 65) sequencing	45.9%	Pham et al[14]
Lao PDRHong Kong	n = 45; Blood donors in Lao PDR	Core and NS5B sequencing	95.6%	Hübschen et al[22]
	n = 1055; 949 non-IVDU and 106 IVDU from all over Hong Kong	Core sequencing	27.1% (23.6% among non-IVDU and 58.5% among IVDU)	Zhou et al[26]
	n = 212; Blood donors	NA	27%	Prescott et al[25]
China	n = 148; Patients from nine regions in China	Core and NS5B sequencing	13% (Genotype 6 was only observed in the South)	Lu et al[24]

Source: Ref. [6], with permission. IVDU: Intravenous drug users; NA: Not available; HCV: Hepatitis C virus; GI: Gastrointestinal; PDR: People's Democratic Republic; NA: Not available.

Table 2 Treatment outcomes of hepatitis C virus genotype 6 (compared to other genotypes)

Ref.	Design/treatment	Genotype	n	SVR	P value1
Dev et al[36]	Retrospective IFN + RBV 52 wk	6	33	82.5%	NR
		1	17	61.9%
Hui et al[37]	Prospective IFN + RBV 52 wk	6	16	62.5%	0.04
		1	24	29.2%
Cheng et al[43]	Retrospective PEG-IFN + RBV (duration not reported)	6	13	69.2%	0.026
		1	61	32.8%
		2	18	77.8%
Fung et al[38]	Prospective PEG-IFN + RBV 52 wk	6	21	85.7%	0.019
		1	21	52.4%
Nguyen et al[40]	Retrospective PEG-IFN + RBV (48 wk for genotype 1 and 6; 24 wk for genotype 2/3)	6	34	74.0%	0.016
		1	70	49.0%
		2/3	63	75.0%
Seto et al[30]	Retrospective IFN/PEG-IFN + RBV 52 wkIFN/PEG-IFN + RBV 52 wk	6	26	92.3%	NR
		1	21	42.9%
Tsang et al[41]	Retrospective PEG-IFN + RBV 48 wk	6	70	75.7%	NR
		1	70	57.1%
Zhou et al[42]	Retrospective PEG-IFN + RBV (48 wk for genotype 1b; 24 wk for genotype 2/3 and 6)	6	22	81.8%	0.068
		1b	39	59.0%
		2/3	42	83.3%
Tangkijvanich et al[48]	Prospective PEG-IFN + RBV (RGT2 for genotype 6; 48 wk for genotype 1; 24 wk for genotype 3)	6	34	76.5%	0.309
		1	16	62.5%
		3	16	81.3%

¹P value between genotype 6 vs genotype 1;

²Response-guided therapy (RGT) define as 24 wk for patients with rapid virological response and 48 wk for those without. PEG-IFN: Pegylated interferon; RBV: Ribavirin; SVR: Sustained virological response.

Table 3 Treatment outcomes of hepatitis C virus genotype 6 by the treatment duration

Ref.	Design/treatment	Duration (wk)	n	SVR	P value
Nguyen et al[44]	Retrospective	24	23	39%	0.044
	PEG-IFN 2a/2b + WB-RBV	48	12	75%
Lam et al[45]	Randomized (1:1)	24	27	70%	0.450
	PEG-IFN 2a + WB-RBV	48	33	79%
Thu-Thuy et al[47]	Randomized (1:2)	24	35	60%	0.240
	PEG-IFN 2a + WB-RBV	48	70	71%
Tangkijvanich et al[48]	Prospective	24 if RVR achieved	25	88%	NR
	PEG-IFN 2a + WB-RBV	48 if no RVR	9	44%

PEG-IFN: Pegylated interferon; RBV: Ribavirin; WB: Weight-based; SVR: Sustained virological response; RVR: Rapid virological response.