- Patient in 1st relapse or refractory to 1st line therapy. Relapse is defined by M-component increase of ≥25% from baseline, in serum and/or urine (the absolute increase in serum must be ≥ 5 g/l - the absolute increase of BJ proteins in urine must be ≥200 mg/24 h). (It is recommended to treat only symptomatic or rapidly evolutive relapses)