In an Italian multicenter study on non-responders, patients received either 3 or 5 MU IFN alpha-2b for six or twelve months in combination with ribavirin. With the most aggressive treatment regime, sustained responses were significantly higher only among genotype 1 patients, not among patients with genotypes 2 or 3, but the sustained response was only 23%, even in patients treated with 5 MU IFN-alpha 3 times per week in combination with ribavirin for 12 months (Medscape Gastroenterology, 3(3) 2001).
Prolonged dosing has been used in patients with genotype 1b, with improved SVR. The treatment lasted for 72 weeks (J Gastroenterol. 2003;38(2):158-63.PMID: 12640530). A 3-year study was done in Japan with 12 non-responder genotype 1b patients. They were given 6 MU of natural IFN three times a week. One patient withdrew. Of the rest, 36% showed a sustained response and 45%, a biolchemical response (Hepatology Research Volume 27, Issue 4, December 2003, Pages 266-271).
