In REALIZE, treatment-experienced patients randomized to the lead-in telaprevir arm received 4 weeks of PegIFN-¦Á-2a (180 ¦Ìg/week) and ribavirin (1000-1200 mg/day), then 12 weeks of telaprevir (750 mg every 8 h) plus PegIFN-¦Á-2a/ribavirin, followed by 32 weeks of PegIFN-¦Á-2a/ribavirin. This subanalysis only included patients in the lead-in telaprevir arm with available week 4 on-treatment response data (n = 240).
After 4 weeks of PegIFN/ribavirin, 90 % of relapsers, 60 % of partial responders, and 41 % of null responders in the lead-in telaprevir arm had ?1 log10 HCV RNA reduction. Sustained virologic response (SVR) rates for telaprevir-treated patients with ?1 versus <1 log10 HCV RNA reduction after the PegIFN/ribavirin lead-in were 94 % versus 62 % in relapsers, 59 % versus 56 % in partial responders and 54 % versus 15 % in null responders.
In prior relapsers and partial responders there is no apparent benefit of assessing response after a PegIFN/ribavirin lead-in with the aim of guiding telaprevir-based treatment. For patients known to be prior null responders, on-treatment response after a 4-week PegIFN/ribavirin lead-in may provide clinically useful prognostic information. However, withholding telaprevir-containing therapy in uncategorised treatment-experienced patient populations (i.e., that could include prior relapsers or partial responders), using response after a PegIFN/ribavirin lead-in could potentially exclude some patients with a high chance of SVR.