The purpose of this study is to evaluate the efficacy, safety, tolerability and pharmacokinetics of VX-147 in high risk APOL1 genotypes and proteinuric kidney disease. 

The purpose of this study is to evaluate the efficacy, safety, tolerability, and pharmacokinetics (PK) of VX-147 in adult and pediatric participants with apolipoprotein L1 (APOL1)-mediated proteinuric kidney disease.

This is a multicenter, double-blind, randomized, placebo-controlled study to evaluate the safety and efficacy of oral difelikefalin administered as a 1 mg tablet once daily compared to placebo in reducing the intensity of itch in advanced chronic kidney disease (CKD) patients with moderate-to-severe pruritus. This study is comprised of an Efficacy Assessment Phase and a Long-term Extension Phase. The Efficacy Assessment Phase includes a double-blind 12-week Treatment Period (Treatment Period 1), and the Long-term Extension Phase includes a double-blind Treatment Period (Treatment Period 2) of up to 52 weeks.