Effect of long-term lamivudine in chronic hepatitis B virus-infected children

To evaluate, retrospectively, biochemical, serological and histological responses in chronic hepatitis B (CHB)-infected children who received combination therapy and continued with prolonged treatment with lamivudine (3TC).

CHB infection was defined as the presence of hepatitis B surface antigen (HBsAg), hepatitis Be antigen (HBeAg) and hepatitis B virus (HBV) DNA in serum screened at 3-month intervals for at least 1 year, serum alanine aminotransferase (ALT) levels >1.5 times the normal limit and CHB with histological activity index (HAI) >5 by liver biopsy. A total of 99 children with CHB infection were treated with IFN-alpha (three times a week, 5 MU/m2) and 3TC (4 mg/kg/d) orally for 6 months. End of therapy response (CR) was defined as ALT normalization, HBV-DNA clearance and e seroconversion. Partial responders (PR) were defined as patients who had ALT normalization and HBV-DNA clearance, but who had not had e seroconversion. Forty-five children with PR at the end of the sixth month continued to receive 3TC alone thereafter. Breakthrough infection was determined as re-emergence of HBV DNA in serum after its clearance. The response rate, side effects and the breakthrough infection rate were examined on prolonged 3TC treatment. Liver biopsy was held in 29 patients at median 32 (14-66) months of 3TC; pre- and post-treatment liver histology was compared.

Pre- and post-treatment evaluation was carried out in 45 children [mean age: 11+/-4.2 years, 31 males (69%), 14 females (31%)] with PR at the end of the sixth month of combination therapy. The initial mean ALT values and HAI scores were 75.6+/-60 IU/l and 8+/-3.3, respectively. 3TC was continued for median 33 (14-66) months and CR was achieved in 15.6% (7/45) and 5.6% (2/36) at the end of first and second year, and 0% (none) at the end of third and fourth year, respectively. Breakthrough incidence was detected in six (13.3%) cases at 12 months and increased to 69.4% (n=25) and 82.4% (n=14) at the end of the second and third years, respectively. Patients with breakthrough continued to receive 3TC. Seroconversion and CR of the mutant virus was achieved in one patient (2.9%) at month 46 of treatment with 3TC. Liver biopsy was held in 29 cases at median 32 (14-66) months of 3TC. Pre- and post-treatment mean HAI scores were 8+/-3.3 and 3.9+/-2.1, respectively (P=0.000). Mean necrosing scores were not different at the beginning and end of therapy (P=1.0). Inflammation, bridging and fibrosis scores decreased to 0.8+/-0.6, 1.3+/-1.2 and 0.6+/-0.8, respectively (P=0.000, P=0.002, P=0.000).

The long-term 3TC usage in children with PR does not induce complete response and is associated with high breakthrough incidence. However, histological improvement is achieved and/or sustained even in children with HBV DNA breakthrough.