<qa>  What is the phase II multicentre study of sofosbuvir plus lediThis is a non-randomized, a single arm, phase II multicentre study of sofosbuvir plus ledipasvir genotype 1 and 4 or sofosbuvir plus velpatasvir genotype 2 and 3 for patients with hepatitis C virus-associated indolent B-cell lymphomas HCV-RNA positive. 