Regulatory Decision Summary for GALEXOS

Health Canada considers that the benefit of Galexos in combination with sofosbuvir for the treatment of genotype 1 chronic HCV in patients with compensated liver disease outweighs the known risks associated with each drug.

Galexos is formulated as a 150 mg caplet and sofosbuvir is formulated as a 400 mg tablet. The recommended dose of this regimen is 150 mg Galexos once daily and 400 mg sofosbuvir once daily. Treatment duration is based on the patient population.

The clinical safety and efficacy of Galexos in combination with sofosbuvir were assessed in two, multicentre, open label, Phase III studies in patients with HCV genotype 1. The efficacy of Galexos in combination with sofosbuvir was assessed by measuring the sustained virologic response rates at follow-up Week 12 (SVR12). The benefits of Galexos in combination with sofosbuvir include high SVR12 rates (95%) in patients without compensated liver disease and a favorable safety profile in difficult-to-treat populations, including peginterferon/ribavirin treatment-experienced patients and patients with compensated liver disease, following 12 weeks of treatment. Based on previous Phase II studies, prolonging the treatment duration to 24 weeks increased the SVR12 rate to >90% in patients with compensated liver disease. A 24 week treatment duration is recommended when Galexos is co-administered with sofosbuvir in this patient population. The SVR12 rates were high regardless of baseline factors such as interleukin 28B genotype, HCV genotype subtype (1a or 1b) or the presence or absence of a Q80K polymorphism in patients without compensated liver disease.

The potential harm associated with Galexos in combination with sofosbuvir consists of a risk of symptomatic bradycardia in patients receiving amiodarorone, especially those also receiving beta blockers or those with underlying cardiac comorbidities and/or advanced liver diseases. An uncertainty associated with the use of Galexos in combination with sofosbuvir is the clinical relevance of the elevations in amylase and lipase levels in the post-market patient population. The potential harms and uncertainties associated with the use of Galexos co-administered with sofosbuvir are described in the Product Monograph for Galexos.

In conclusion, the data presented supported the removal of the conditions for Galexos in combination with sofosbuvir for the treatment of genotype 1 chronic HCV in patients with compensated liver disease.