18 PHARMACOLOGY Gene mutation predicts response to IFN-a in chronic HCV infection

A correlation between responses to interferon-a therapy for chronic hepatitis C virus (HeV) type 1 b infection and mutations in an amino acid sequence of the non structural protein (NS) 5A of the genomic sequence of HCV-l b has been identified by researchers in Japan.

They consider that this finding may be useful in predicting responses to interferon-a therapy in this indication; HCV-l b has been known to be resistant to interferon-a, with complete response rates ranging between 10 and 40% of treated patients. While interferon-a is the only currently available treatment for chronic HCV infection, the researchers suggest that interferon-a therapy is unsuitable for patients infected with interferon-resistant HCV-l b with wild-type or intermediate-type NS5A2209_2248 sequences.

Oear difference in responses Their study involved 84 patients with chronic

HCV-l b infection who had received treatment with human lymphoblastoid interferon-a or recombinant interferon-a-2a or -2b. Nucleotide sequencing of the NS5A2209-2248 region revealed 3 distinct types of amino acid sequences among these patients: wild-type (30 patients), mutant-type (16) and intermediate-type (38).

All 16 patients with the mutant-type amino acid sequence had complete responses, whereas all 30 patients with the wild-type sequence had no response to therapy. 33/38 patients with intermediate-type amino acid sequences had no response to therapy. Enomoto N. Salruma I. Asahina Y. Kurosaki M. Murakami T. et aI. Mutations in the nonstructural protein SA gene and response to interferon in patients with chronic hepatitis C virus Ib infection. New England Journal of Medicine 334: 77·81. II Jan 1996 Il0041....,

20 Jan 1996 INPHARMA- 0156-270319611020·000181$01.00° Adialmernatlonal Limltad 1996. All rights reMrVed