AbbVie announced that results from part one of the phase 2 portion of its phase2/3 open-label study, TURQUOISE-I, in genotype 1 chronic hepatitis C patients with human immunodeficiency virus type 1 (HIV-1) co-infection were published online in The Journal of the American Medical Association (JAMA). Additional sub-analyses also will be presented in both oral and poster presentations on Feb. 26, at the Annual Conference on Retroviruses and Opportunistic Infections (CROI) in Seattle, Wash.

As published recently in JAMA, and originally presented at The Liver Meeting 2014, the TURQUOISE-I study showed patients co-infected with genotype 1 (GT1) hepatitis C virus (HCV) and HIV-1 receiving VIEKIRA PAK and ribavirin (RBV) for 12 weeks or 24 weeks achieved sustained virologic response rates 12 weeks post-treatment (SVR12) of 94 per cent (n=29/31) and 91 per cent (n=29/32), respectively. The SVR12 rates were 91 per cent (n=51/56) for subjects with HCV GT1a infection and 100 percent (n=7/7) for those with HCV GT1b infection.

"It is common for people to live with both GT1 chronic HCV and HIV, but data supporting treatment of chronic HCV in these co-infected patients have been limited," says Michael Severino, MD, executive vice president, research and development and chief scientific officer, AbbVie. "TURQUOISE-I is one of the few dedicated studies looking specifically at this historically difficult-to-treat population and we are proud to offer the HCV community an important new treatment option."

VIEKIRA PAK is contraindicated with efavirenz (Sustiva) because co-administration is poorly tolerated and results in liver enzyme elevations. The ritonavir component of VIEKIRA PAK is an HIV-1 protease inhibitor and can select for HIV-1 protease inhibitor resistance.

To reduce this risk, HCV/HIV-1 co-infected patients should also be on a suppressive antiretroviral (ART) drug regimen. The most common adverse events occurring in at least 10 percent of patients in TURQUOISE-I were fatigue (48 per cent), insomnia (19 per cent), nausea (17 per cent), headache (16 per cent), itching (13 per cent), cough (11 per cent), irritability (10 per cent), and yellowing of the eyes (10 per cent). In this analysis of the TURQUOISE-I study, certain laboratory values in patients taking paritaprevir/r/ombitasvir and dasabuvir with RBV were examined, including hemoglobin, CD4+ T cells, and lymphocyte count

TURQUOISE-I is an ongoing phase 2/3, multi-center, randomised, open-label study evaluating the efficacy and safety of VIEKIRA PAK (ombitasvir, paritaprevir, ritonavir (25/150/100 mg once daily) and dasabuvir (250 mg twice daily) with RBV (weight based dosing of 1000 mg or 1200 mg per day divided twice daily) for 12 or 24 weeks in adult patients with chronic GT1 HCV infection with or without compensated liver cirrhosis who are also infected with HIV-1.

Study patients were either new to therapy (treatment-naïve) or had failed previous treatment with pegylated interferon and RBV (treatment-experienced), had a stable immune status (CD4+ counts of =200 cells/mm3 or CD4+ per cent =14 per cent). Patients were on a stable HIV-1 ART regimen that included tenofovir disoproxil fumarate plus emtricitabine or lamivudine, administered with ritonavir-boosted atazanavir or raltegravir. Patients on atazanavir stopped the ritonavir component of their HIV-1 ART regimen upon initiating treatment with VIEKIRA PAK + RBV. Atazanavir was taken with the morning dose of VIEKIRA PAK. The ritonavir component of the HIV-1 ART regimen was restarted after completion of treatment with VIEKIRA PAK and RBV. Of the five patients who were non-responders, one experienced virologic failure, one discontinued treatment, one experienced relapse and two patients had evidence of HCV reinfection post-treatment. Based on the results of this study, prescribers should follow the same dosing recommendations for mono-infected patients as outlined in the VIEKIRA PAK prescribing information.

Elevations in total bilirubin were the most common laboratory abnormality, were mainly composed of indirect bilirubin, and were not associated with elevations in commonly measured liver enzymes. Reductions in RBV dose because of anaemia or reduced haemoglobin occurred in 10 per cent of patients (n=6/63); all six patients achieved SVR12.

VIEKIRA PAK (ombitasvir, paritaprevir, ritonavir tablets; dasabuvir tablets) has been studied in a broad range of genotype 1 (GT1) patients with chronic hepatitis C virus (HCV) infection, ranging from treatment-naïve to some of the most difficult to treat, such as patients with compensated (mild, Child-Pugh A) cirrhosis of the liver, HCV/HIV-1 co-infection, liver transplant recipients with normal hepatic function and mild fibrosis, and those who have failed previous treatment with pegylated interferon (pegIFN) and ribavirin (RBV). VIEKIRA PAK is not recommended in patients with moderate hepatic impairment (Child-Pugh B), and is contraindicated in patients with severe hepatic impairment (Child-Pugh C). VIEKIRA PAK consists of the fixed-dose combination of ombitasvir 25mg (an NS5A inhibitor), paritaprevir 150mg (an NS3/4A protease inhibitor), and ritonavir 100mg (an inhibitor of an enzyme that breaks down paritaprevir), dosed once daily with a meal, and dasabuvir 250mg (a non-nucleoside NS5B palm polymerase inhibitor), dosed twice daily with a meal. VIEKIRA PAK is taken for 12 weeks, except in GT1a patients with cirrhosis, who should take it for 24 weeks. Ribavirin should be co-administered in GT1a patients, and in all patients who have cirrhosis or who have received a liver transplant.

Paritaprevir was discovered during the ongoing collaboration between AbbVie and Enanta Pharmaceuticals for HCV protease inhibitors and regimens that include protease inhibitors. Paritaprevir is being investigated by AbbVie for use in combination with AbbVie's other investigational medicines for the treatment of hepatitis C.

VIEKIRA PAK was granted priority review and designated as a Breakthrough Therapy by the US FDA, a status given to medicines or regimens that may offer substantial improvement over available therapies.