Rituximab based therapy followed by autologous stem cell transplantation leads to superior outcome and high rates of PCR negativity in patients with indolent B-cell lymphoproliferative disorders.

Autologous stem cell transplantation (ASCT) and rituximab based therapy represent effective treatments of indolent B-cell lymphoproliferative disorders (B-LPDs) that often induce molecular remission (MR). We assessed the impact of MR after treatment on prognosis of 57 patients with indolent B-LPDs. We also evaluated the impact of therapy on patients' outcome. Failure to achieve MR was identified as an independent risk factor regardless of treatment modality. PCR positive patients had shorter progression free survival (PFS) in contrast with patients in MR after rituximab (median 0.75 and 2.5 years respectively; p=0.006) or patients in MR after rituximab followed by ASCT (median 3.3 years; p=0.0032). PCR positive patients had a 5-year overall survival (OS) of only 40% compared to a 5-year OS of 76% for PCR negative patients after rituximab (p=0.0186) and 86% PCR negative patients after rituximab with ASCT (p=0.003). All nine patients transplanted with PCR positive graft relapsed (p=0.0023) with shorter PFS (p=0.0008). Rituximab based therapy induced MR in 25 (64%) compared to 18 (100%) patients after rituximab followed by ASCT (p=0.0025). We observed no difference in PFS between the transplant group (3.3 years) and rituximab based treatment (1.9 years), but the 5-year OS of patients with transplant was 85 and 59% respectively (p=0.0271). Patients with indolent B-LPDs who achieve MR have better prognosis. Rituximab based therapy induces MR in high number of patients, which can be further improved by ASCT and patients have an excellent outcome. PCR positive harvest represents a high risk of relapse after ASCT.