FDA Hepatitis Update/ VIEKIRA XR - DOSAGE AND ADMINISTRATION

FDA Hepatitis Update

On July 22, 2016 FDA approved VIEKIRA XR extended release tablets. VIEKIRA XR is a fixed dose combination tablet of previously approved antiviral drugs containing dasabuvir, a hepatitis C virus non-nucleoside NS5B palm polymerase inhibitor, ombitasvir, a hepatitis C virus NS5A inhibitor, paritaprevir, a hepatitis C virus NS3/4A protease inhibitor, and ritonavir, a CYP3A inhibitor, indicated for the treatment of adult patients with chronic hepatitis C virus (HCV):

• genotype 1b infection without cirrhosis or with compensated cirrhosis
• genotype 1a infection without cirrhosis or with compensated cirrhosis for use in combination with ribavirin.

VIEKIRA XR differs from VIEKIRA Pak in that all of the HCV antiviral drugs are now combined in one fixed dose combination tablet for once daily dosing. The daily mg dose of dasabuvir is higher, and dasabuvir is administered once daily as part of the fixed dose combination.

The recommended dosage of VIEKIRA XR is three tablets taken orally once daily. VIEKIRA XR must be taken with a meal.

The approval of VIEKIRA XR is based on comparability of bioavailability for each of the components in VIEKIRA XR compared to that of the previously approved formulations in VIEKIRA Pak. A clinical trial to evaluate the efficacy and safety of Viekira XR FDC was not required because the efficacy and safety of the components of VIEKIRA XR were established previously in six clinical trials enrolling 2,308 Chronic Hepatitis C patients with and without cirrhosis.

DOSAGE AND ADMINISTRATION
Testing Prior to Initiation of VIEKIRA XR
Prior to initiation of VIEKIRA XR, assess for laboratory and clinical evidence of hepatic decompensation.

Recommended Dosage in Adults
VIEKIRA XR is a 4-drug fixed-dose combination, extended-release tablet containing 200 mg of dasabuvir, 8.33 mg of ombitasvir, 50 mg of paritaprevir, and 33.33 mg of ritonavir. The recommended dosage of VIEKIRA XR is three tablets taken orally once daily.

• VIEKIRA XR must be taken with a meal because administration under fasting conditions may result in reduced virologic response and possible development of resistance.
• Swallow tablets whole. Splitting, crushing, or chewing tablets may compromise the extended-release performance, efficacy, and/or safety of VIEKIRA XR.
• For optimal release of dasabuvir, alcohol should not be consumed within 4 hours of taking VIEKIRA XR.   

VIEKIRA XR is used in combination with ribavirin (RBV) in certain patient populations (see Table 1). When administered with VIEKIRA XR, the recommended dosage of RBV is based on weight: 1000 mg/day for subjects

For patients with HCV/HIV-1 co-infection, follow the dosage recommendations in Table 1.
Table 1 shows the recommended VIEKIRA XR treatment regimen and duration based on patient population.

Table 1. Treatment Regimen and Duration by Patient Population (Treatment-Naïve or Interferon-Experienced)

Patient Population	Treatment*	Duration
Genotype 1a, without cirrhosis	VIEKIRA XR + ribavirin	12 weeks
Genotype 1a, with compensated cirrhosis (Child-Pugh A)	VIEKIRA XR + ribavirin	24 weeks**
Genotype 1b, with or without compensated cirrhosis (Child-Pugh A)	VIEKIRA XR	12 weeks

*Note: Follow the genotype 1a dosing recommendations in patients with an unknown genotype 1 subtype or with mixed genotype 1 infection.
**VIEKIRA XR administered with ribavirin for 12 weeks may be considered for some patients based on prior treatment history

Use in Liver Transplant Recipients
In liver transplant recipients with normal hepatic function and mild fibrosis (Metavir fibrosis score 2 or lower), the recommended duration of VIEKIRA XR with ribavirin is 24 weeks, irrespective of HCV genotype 1 subtype. When VIEKIRA XR is administered with calcineurin inhibitors in liver transplant recipients, dosage adjustment of calcineurin inhibitors is needed.

Hepatic Impairment
VIEKIRA XR is contraindicated in patients with moderate to severe hepatic impairment (Child Pugh B and C)
The complete label for VIEKIRA XR is available at Drugs@FDA.

VIEKIRA XR full Prescribing Information, including the Medication Guide.
VIEKIRA PAK full Prescribing Information, including the Medication Guide.

AbbVie Press Release
AbbVie Receives U.S. FDA Approval of Once-Daily VIEKIRA XR™ (dasabuvir, ombitasvir, paritaprevir and ritonavir) for the Treatment of Genotype 1 Chronic Hepatitis C