Long-term lamivudine therapy for children with HBeAg-positive chronic hepatitis B.

One year of lamivudine treatment results in increased hepatitis B e antigen (HBeAg) seroconversion and serum hepatitis B virus (HBV) DNA negativity in children with chronic hepatitis B and high serum alanine aminotransferase concentrations. Two hundred seventy-six children who participated in a 1-year randomized, placebo-controlled study of lamivudine were enrolled in a 24-month, open-label extension. Patients were stratified into two groups based on HBeAg status at week 48 of the previous study: 213 HBeAg-positive children were entered into a treatment arm, and 63 HBeAg-negative children were entered into an observation arm to evaluate durability of HBeAg loss. In the treatment arm, 28 of 133 (21%) children previously treated with lamivudine and 23 of 77 (30%) children who previously received placebo achieved the primary end point: virological response (VR) (HBeAg loss and HBV DNA negativity) at month 24. The incidence of YMDD (tyrosine, methionine, aspartate, aspartate) mutations at month 24 was 64% (66/103) in the children previously treated with lamivudine and 49% (34/70) in those previously treated with placebo. The incidence of VR at month 24 was 5% (5/100) for patients with YMDD mutant HBV and 54% (39/72) for patients without. The durability of response in the observation arm was 89% (48/54) at month 24. In conclusion, further clinical response was seen over the 24-month open-label study period in children who had not initially achieved a VR after 12 months of lamivudine treatment. However, the incidence of YMMD mutations increased over time and resulted in lower response rates. VR was maintained in most patients who had initially responded to lamivudine in the first 12 months.

Clinical trial of lamivudine in children with chronic hepatitis B.

BACKGROUND: Lamivudine therapy is effective for chronic hepatitis B infection in adults. We evaluated the efficacy and tolerability of lamivudine as a treatment for chronic infection with hepatitis B virus (HBV) in children. METHODS: Children with chronic hepatitis B were randomly assigned in a 2:1 ratio to receive either oral lamivudine (3 mg per kilogram of body weight; maximum, 100 mg) or placebo once daily for 52 weeks. The primary end point was virologic response (defined by the absence of serum hepatitis B e antigen and serum HBV DNA) at week 52 of treatment. RESULTS: Of the 403 children screened, 191 were randomly assigned to receive lamivudine and 97 to receive placebo. The rate of virologic response at week 52 was higher among children who received lamivudine than among those who received placebo (23 percent vs. 13 percent, P=0.04). Lamivudine therapy was well tolerated and was also associated with higher rates of seroconversion from hepatitis B e antigen to hepatitis B e antibody, normalization of alanine aminotransferase levels, and suppression of HBV DNA. CONCLUSIONS: In children with chronic hepatitis B, 52 weeks of treatment with lamivudine was associated with a significantly higher rate of virologic response than was placebo.

Caracterización genotípica de la infección por el virus de hepatitis C en niños / Genotype characterization of hepatitis C virus infection in children

Hepatitis C virus (HCV) infection in children was assessed by RT-nested PCR of the 5'untranslated region (5'UTR) of the viral genome combined with virus genotyping, performed by restriction fragment length polymorphism (RFLP). We analysed HCV infection in 64 children and in 9 HCV chronically infected mothers corresponding to 10 of them. Thirty two children were positive for serum HCV RNA as determined by RT-nested PCR. The viremia was analysed in consecutive samples of 25 children. Nine children (36 per cent) were always positive for HCV RNA, in 5 (20 per cent) a positive RT-nested PCR turned negative in subsequent samples, other 9 (36 per cent) showed alternating RT-nested PCR results and in 2 (8 per cent) the RT-nested PCR turned positive after an initial negative result. The HCV genotype distribution was studied in 27/32 children and in 9 mothers, and it was similar to that reported in the literature for adult and pediatric patients in our country. Genotype 1 was predominant in our population. HCV genotype did not change in the same patient during the time of this study. HCV genotype was the same in mother-infant pairs. We could not establish a correlation between HCV genotype and vertical transmission of HCV. This study will be helpful to further analyze HCV behavior during pediatric infection and the host's response in the initial stages of it.

Caracterización genotípica de la infección por el virus de hepatitis C en niños / Genotype characterization of hepatitis C virus infection in children

Hepatitis C virus (HCV) infection in children was assessed by RT-nested PCR of the 5untranslated region (5UTR) of the viral genome combined with virus genotyping, performed by restriction fragment length polymorphism (RFLP). We analysed HCV infection in 64 children and in 9 HCV chronically infected mothers corresponding to 10 of them. Thirty two children were positive for serum HCV RNA as determined by RT-nested PCR. The viremia was analysed in consecutive samples of 25 children. Nine children (36 per cent) were always positive for HCV RNA, in 5 (20 per cent) a positive RT-nested PCR turned negative in subsequent samples, other 9 (36 per cent) showed alternating RT-nested PCR results and in 2 (8 per cent) the RT-nested PCR turned positive after an initial negative result. The HCV genotype distribution was studied in 27/32 children and in 9 mothers, and it was similar to that reported in the literature for adult and pediatric patients in our country. Genotype 1 was predominant in our population. HCV genotype did not change in the same patient during the time of this study. HCV genotype was the same in mother-infant pairs. We could not establish a correlation between HCV genotype and vertical transmission of HCV. This study will be helpful to further analyze HCV behavior during pediatric infection and the hosts response in the initial stages of it. (Au)

Genomic and phylogenetic analysis of hapatitis C virus strains from Argentina

HCV genomic characterization was performed by nucleotide sequence analysis (n=50) combined with restriction fragment length polymorphism (RFLP) of the 5'UTR region in 82 isolates coresponding to different Argentine groups. Genotype 1 was detected in 70.7 percent of the samples (58 out of 82), genotype 2 in 21.9 percent (18 of 82) and genotypes 3 in the remaining 6 sera (7.3 percent). HCV ib subtype contributed with 35.3 percent to the whole population studied (29 of 82) and was detected in 6 out of 21 sporadic cases. Besides their epidemiological significance, these results should be taken into account when future vaccines are considered on the basis of geographical HCV genotypic prevalence.

Genomic and phylogenetic analysis of hapatitis C virus strains from Argentina

HCV genomic characterization was performed by nucleotide sequence analysis (n=50) combined with restriction fragment length polymorphism (RFLP) of the 5UTR region in 82 isolates coresponding to different Argentine groups. Genotype 1 was detected in 70.7 percent of the samples (58 out of 82), genotype 2 in 21.9 percent (18 of 82) and genotypes 3 in the remaining 6 sera (7.3 percent). HCV ib subtype contributed with 35.3 percent to the whole population studied (29 of 82) and was detected in 6 out of 21 sporadic cases. Besides their epidemiological significance, these results should be taken into account when future vaccines are considered on the basis of geographical HCV genotypic prevalence. (AU)