Mantle cell lymphoma is considered to have the worst outcome of all non-Hodgkins lymphomas. Since 1997, the Nordic Lymphoma Group has conducted phase II studies in order to improve the results for this lymphoma subtype. The first study included high-dose therapy with autologous stem cell support in the first line of treatment. The results showed the importance of a high quality response to pre-transplant induction treatment, and that CHOP-based regimen alone did not achieve this. Thus, the second trial was designed to improve remissions by including Rituximab and high-dose Ara-C. Results now show that a high rate of molecular remission in the bone marrow was achieved, and the 3-year FFS was improved in comparison to the first study (80% vs 24%). Furthermore, patient who had a molecular relapse (t(11;14) or IgV-gene) were treated with 4 doses of Rituximab and many converted back to be PCR negative.