There are no data on the use of Viekirax and ribavirin in patients with HCV genotype 4 infection with compensated cirrhosis and therefore the optimal treatment duration has not been established. Based on in vitro antiviral activity and available clinical data in HCV genotype 1, a conservative treatment duration of 24 weeks is recommended for patients with HCV genotype 4 and compensated cirrhosis.

Co-administration with other direct-acting antivirals against HCV

Viekirax safety and efficacy have been established in combination with dasabuvir and/or ribavirin. Co-administration of Viekirax with other antivirals has not been studied and therefore cannot be recommended.

Retreatment

The efficacy of Viekirax in patients previously exposed to Viekirax, or to medicinal products of the same classes as those of Viekirax (NS3/4A- or NS5A inhibitors), has not been demonstrated. Concerning cross-resistance, see also section 5.1.

Pregnancy and concomitant use with ribavirin

When Viekirax is used in combination with ribavirin, women of childbearing potential or their male partners must use an effective form of contraception during the treatment and for 6 months after the treatment as recommended in the Summary of Product Characteristics for ribavirin. Refer to the Summary of Product Characteristics for ribavirin for additional information.

ALT elevations

During clinical trials with Viekirax and dasabuvir with or without ribavirin, transient elevations of ALT to greater than 5 times the upper limit of normal occurred in approximately 1% of subjects (35 of 3,039). ALT elevations were asymptomatic and generally occurred during the first 4 weeks of treatment, without concomitant elevations of bilirubin, and declined within approximately two weeks of onset with continued dosing of Viekirax and dasabuvir with or without ribavirin.

These ALT elevations were significantly more frequent in the subgroup of subjects who were using ethinylestradiol-containing medicinal products such as combined oral contraceptives or contraceptive vaginal rings (6 of 25 subjects); (see section 4.3). In contrast, the rate of ALT elevations in subjects using other types of estrogens as typically used in hormonal replacement therapy (i.e., oral and topical estradiol and conjugated estrogens) was similar to the rate observed in subjects who were not using estrogen-containing products (approximately 1% in each group).

Patients who are taking ethinylestradiol-containing medicinal products (i.e. most combined oral contraceptives or contraceptive vaginal rings) must switch to an alternative method of contraception (e.g., progestin only contraception or non-hormonal methods) prior to initiating Viekirax and dasabuvir therapy (see sections 4.3 and 4.5).

Although ALT elevations associated with Viekirax and dasabuvir have been asymptomatic, patients should be instructed to watch for early warning signs of liver inflammation, such as fatigue, weakness, lack of appetite, nausea and vomiting, as well as later signs such as jaundice and discoloured faeces, and to consult a doctor without delay if such symptoms occur. Routine monitoring of liver enzymes is not necessary. Early discontinuation may result in drug resistance, but implicati