THERAPY OF HEPATITIS-C - INTERFERON ALFA-N1 TRIALS

Interferon alfa-n1 is produced from a lymphoid cell line and consists of multiple alpha interferon subtypes, Early studies indicated that in terferon alfa-n1 was effective against hepatitis C, and a meta-analysi s of published trials indicated that it was equally likely as recombin ant alpha interferons to produce an end-of-treatment biochemical and h istological response, However, there appeared to be a lower rate of po sttreatment relapse after a 6-month course of interferon alfa-n1, so t hat the sustained response rate was 25% compared with 16% for recombin ant alpha interferons, Subsequently, the efficacy of interferon alfa-n 1 has been compared with recombinant alpha interferon directly in two large multicenter studies, The 096 International Hepatitis Comparative Study compared alfa-n1 with interferon alfa-2b in doses of 3 million units (MU) three times weekly for 24 weeks In a total of 1,071 patient s. Biochemical end-of-treatment response rates were similar (35% for a lfa-n1; 38% for alfa-2b), as were virological and histological respons es. Relapse occurred more frequently after interferon alfa-2b, so that sustained biochemical (10.3% vs. 6.7%) and virological responses al 1 2 months were higher for alfa-n1, In a second study from Italy, interf eron alfa-n1 was compared with interferon alfa-2a, using higher doses (6 MU three times weekly) until a biochemical response was obtained, a nd then using 3 MU three times weekly for a total of 12 months, The co mbined biochemical and virological sustained response rates were highe r than reported with 6 months of treatment and were similar for alfa-n 1 (17%) as for alfa-2a (16%). The superiority of 12 versus 6 months of treatment was also confirmed in the large multicenter 091 European Co mparative Treatment Schedules study of 440 patients given four differe nt regimens of therapy, Sustained biochemical response rates were 6% i n patients who received 3 MU three times weekly for 6 months and 19% i n those who received this dose for 12 months, When given for 12 months , there was no advantage to a slightly higher dose of interferon alfa- n1 (5 MU three times weekly). Thus, therapy with interferon alfa-n1 pr oduces sustained response rates equivalent to the best obtained with r ecombinant alpha interferon. The optimal treatment regimen appears to be 3 MU given three times weekly For 12 months.