High-dose chemotherapy with autologous stem cell transplantation as first-line therapy for primary CNS lymphoma in patients younger than 60 years: a multicenter phase II study of the GOELAMS group.

The optimum treatment of primary CNS lymphoma (PCNSL) is not yet determined. The objective of this study was to assess the safety and efficacy of initial methotrexate-based chemotherapy followed by high-dose chemotherapy (HDT) with autologous stem cell transplantation (ASCT) in patients with newly diagnosed PCNSL. Twenty-five patients received two courses of initial chemotherapy combining methotrexate, etoposide, carmustine and methylprednisolone, and one course of ifosfamide-cytarabine followed by peripheral stem cell collection. Seventeen responsive patients then received HDT using carmustine, etoposide, cytarabine and melphalan with autologous stem cell rescue. After ASCT for responding patients or after salvage therapy for non-responders, whole brain radiation therapy at a dose of 30 Gy was delivered. The objective response rate to the induction chemotherapy was 84%. Four of the 21 responding patients did not have ASCT because of toxicity or refusal. With a median follow-up time of 34 months, the projected event free survival rate is 46% at 4 years. Projected overall survival is 64% at 4 years. Sixteen patients are actually in continuous complete response. No evidence of late treatment-related toxicity was observed. This treatment approach appears feasible in newly diagnosed PCNSL with encouraging results.

Proliferation of human progenitor cells in a long-term culture system is more efficiently sustained by the addition of Flt-3 ligand or megakaryocyte growth and development factor than by Kit ligand.

INTRODUCTION: We compared the effects of the early-acting growth factors (GF), Flt-3 ligand (FL), c-Kit ligand (KL), and leukemia inhibitory factor (LIF), and the late-acting GF, granulocyte-colony stimulating factor (G-CSF) and megakaryocyte growth and development factor (MGDF), added alone in human long-term marrow culture (LTMC). MATERIALS AND METHODS: The GF were used in primary cultures of mononuclear cells (MNC) and in cocultures of CD34+ cells on murine preestablished MS-5 stromal layers. GF activity was assessed as nonadherent and adherent progenitor cell production and cobblestone area formation at week 5. RESULTS: In this system, only FL, KL, and MGDF significantly stimulated early stages of hematopoiesis, whereas only G-CSF stimulated the proliferation of mature progenitor cells within the granulo-monocyte lineage and no effect was observed with LIF. FL displayed the strongest activity, and MGDF was more efficient than KL, both in primary cultures of MNC and in cocultures of CD34+ cells. However, the stimulatory effects of these GF used alone were dependent on the presence of a stromal layer. CONCLUSION: These LTMC data emphasize the particular roles for FL and MGDF in the stimulation of primitive hematopoiesis.