Abstract Introduction: We report the SVR12 final analysis of a phase 3 study of telaprevir in combination with peginterferon (P)/ribavirin (R) in HCV-genotype 1, treatment-naïve and -experienced patients with HCV/HIV co-infection (INSIGHT). Materials and Methods: Patients receiving stable, suppressive HIV antiretroviral (ARV) therapy, containing atazanavir/ritonavir, efavirenz, darunavir/ritonavir, raltegravir, etravirine or rilpivirine, received telaprevir 750 mg q8h (1125 mg q8h if on efavirenz) plus P (180 µg once-weekly) and R (800 mg/day) for 12 weeks, followed by an additional 12 weeks (non-cirrhotic HCV treatment-naïve and relapse patients with extended rapid viral response [eRVR]) or 36 weeks (all others) of PR alone. Analysis was performed when all patients had completed the follow-up visit of 12 weeks after last planned dose. Results: One hundred sixty-two patients were enrolled and treated (65 efavirenz, 59 atazanavir/ritonavir, 17 darunavir/ritonavir, 17 raltegravir, 4 etravirine). Mean age was 45 years, 78% were male, 92% were Caucasian; mean CD4 count was 687 cells/mm3. Sixty four patients (40%) were HCV treatment-naïve and 98 (60%) were treatment experienced (29 relapsers, 18 partial responders and 51 null responders). 64% were subtype 1a. 30% had bridging fibrosis (17%) or cirrhosis (13%). 19% of patients discontinued telaprevir, including 9% due to an adverse event (AE), 8% reaching a virologic endpoint and 2% for other reasons (non compliance or not defined). Treatment responses are shown in Table 1. There were no HIV RNA breakthroughs. Most frequently reported (≥20% patients) AEs were pruritus 43%; fatigue 27%; rash 34%, anorectal events 30% and influenza-like illness (25%). Anemia was reported in 15% of patients; grade ≥3 haemoglobin decrease occurred in 2.5% of patients. 6% of patients experienced serious AEs. Conclusions: In this phase 3 study of HIV-infected, HCV treatment-naïve and -experienced patients, 49% achieved eRVR and 57% reached SVR12. In patients with an eRVR, SVR12 rates were >80%, irrespective of prior treatment history.