The FDA proved recommended adult dose for interferon be 30-35 MIU/week or 5MIU daily or 10 MIU TIW × 16-26 weeks, which was not based on Kg body weight or body surface area. As per our clinical experience we found this dose quite unreasonable for Indian adults. Thus based on ICMR recommenda-tions for reference Indian male(2), mean weight 57.5 Kg, an interferon dose of 3-5 MIU TIW equivalent to 52, 173 to 86, 456 IU/Kg body weight was calculated. Due to unavailability of standard pediatric IFN dose, we agreed to use an estimated dose per Kg body weight from our standardized adult dose under a protocol. Keeping in mind the normal variance of ±2 SD in the ideal body weights and unknown nature of adverse experiences in Indian children we agreed to use IFN only in a "titrated dose" of 50-75000 IU/Kg body weight. Subsequently we conducted a pilot study to monitor the adverse experiences and therapeutic effect of IFN in children in a clinical trial(3). Further consecutive pediatric patients of chronic HBV were enrolled in this study.

We agree with Poddar et al. on the advantages of calculating drug doses based on the body surface area (BSA) in children. But in absence of approved recommendations for BSA nomograms specific for Indian children, any BSA based protocol using calculation based on formulae (which could have been fallacious) did not seem convincing. We disagree with Poddar et al. for recommending the pediatric dose of 3-10 MIU/m2 in chronic HBV infection. The stated references in support of it are reviews and individual experiences. The present recommendations for children (6 MIU/m2 TIW with maximum limit of 10 MIU/week × 16-24 weeks) by the FDA(4,5) stands since 1998-2000 and is based on a single multinational RCT by Sokal et al.(6) as detailed in our discussion. The mean therapeutic dose utilized in our clinical trial was very much below this safety limit. However, BSA standardization of specific therapeutic doses Indian children needs to be done. Presently, standardized body weight based titrated dose seems to work fine.

We would also like to remind Poddar et al. that, we have only included compensated Child’s staged A and B chronic liver disease patients. Thus, the possibility of an inappropriate body weight calculation seems to be remote. Moreover in view of limited adverse experiences and the high anti viral responses seen, we believe the titrated IFN dosing was therapeutically adequate. It is also being highlighted that we strictly included children below 12 years of age in the range of 2-12 years and not as erroneously printed.

We agree on the possibility of delayed responses to interferon therapy in children which improved from 44% to 52% in the mean follow up period of 16 months (unpublished data). As a point of note to the readers, we would like to detail the 6 cases with problematic histological diagnosis. Out of these, 3 (horizontally transmitted group) had inadequate liver tissue but sufficient to warrant possible cirrhosis. All the remaining three (2 vertically + 1 horizontally transmitted group) children had a history suggestive of chronic hepatitis and no apparent clinical features or cirrhosis.

It is further brought to the notice that, the mean ALT in the vertically and horizontally transmitted groups was more than 1.5 times the normal, none had a normal ALT on inclusion, thus it would be inappropriate to assume that an "immune tolerant" type of infection plagued our group of patients. We also do not warrant caution against IFN therapy in "immune tolerant" infection. Many recent reports suggest a decreased immediate antiviral response in them, but not without long-term benefits(7).

Guptan RC,
Thakur V,
Sarin SK,
Department of Gastroenterology,
G.B. Pant Hospital,
New Delhi 110 002, India.