* Authors on the Steering Committee contributed equally to the oversight of the study, including study design and maintaining the quality of study conduct. CONTRIBUTORS Owen O'Connor, Barbara Pro, Tim Illidge and Lorenz Trumper formed the ECHELON-2 steering committee and contributed equally to the oversight of the study, including study design and maintaining the quality of study conduct.

2153 Poster Board II-130 Hematopoietic progenitor and stem cells (HSC) reside in the bone marrow and have to be mobilized into the circulation prior to being collected by apheresis. The number of apheresis procedures needed and the success of transplantation are determined by the efficiency of stem cell mobilization. Between January 2004 to December 2008, 840 patients (pt) with the following diagnoses were scheduled to undergo leukapheresis for autologous transplantations: multiple myeloma (MM, n=602) and non-Hodgkin's lymphoma (NHL, n=238). Mobilization data and transplantation outcome were analyzed retrospectively. Most of the pt mobilized readily: close to 85% of the pt had a level of 20/μL to >500/μL of CD34+ cells at the peak of stimulation. Of the 840 pt, 129 (15.3%) were considered to be “Poor Mobilizers” (PM), defined as pt who had a peak concentration of <20/μL of CD34+ cells upon stimulation with G-CSF subsequent to induction chemotherapy appropriate for the respective disease. Among them, 38 (4.5%) pt had CD34+ levels of between 11-19/μL at maximum stimulation, defined as borderline PM, 49 (5.8%) pt had CD34+ levels of between 6-10/μL, defined as relative PM and 42 pt (5%) with levels of <5/μL, defined as absolute PM. We have analyzed the relationship between poor mobilizations with types of disease (MM versus NHL), sex, age, body weight, previous irradiation, number of cycles of previous combination chemotherapy, and pretreatment with melphalan. There was no difference in the incidence of PM between pt with MM versus those with NHL. Sex, age, body weight and previous irradiation therapy did not make any significant difference. Only the number of cycles of previous chemotherapy (p=0.0034), and previous treatment with melphalan (p=0.0078) had a significant impact on the ability to mobilize. Secondary strategies to mobilize HSC from the 33 who failed included: (1) Administration of another cycle of induction chemotherapy + G-CSF. The goal of harvesting 2.0 × 10exp6 CD34+ cells/kg body weight could be accomplished in 7 of 21 of these patients. (2) G-CSF alone for 4 days (up to 8 days of stimulation) after hematopoietic recovery from previous induction chemotherapy. The goal could be achieved in 2 of the 9 patients thus mobilized. (3) Plerixafor within the compassionate use program. The goal was accomplished in 7 of 8 patients within one cycle of mobilization. All 8 could be transplanted successfully. (4) Bone marrow harvest in lieu of collection of peripheral HSC in 5 patients. For the good mobilizers, the median time to recovery of the WBC to 1.0/nL or granulocyte of 0.5/nL (whichever is sooner) was 13 days with a range of 7 to 22 days, whereas for the PM group it was 14 days with a range of 8 to 37 days. This difference was statistically not significant. The median time to recovery of the platelets counts to an unmaintained level of >20/nL was 11 days with a range of 6 to 17 days for the good mobilizers, whereas for the PM it was 11 days with a range of 7 to 32 days. Again this difference was statistically not significant. The majority of the patients nowadays intended for autologous transplantations were able to mobilize readily. According to the criteria proposed in this study, 15.3% were considered to be “Poor Mobilizers”, 4.5% borderline PM, 5.8% relative PM and 5% absolute PM. No significant difference was found between patients with NHL versus MM. Sex, age, body weight and previous irradiation therapy did not make any difference. Only the number of cycles of previous chemotherapy (p=0.0034), and previous treatment with melphalan (p=0.0078) had a significant impact. Above all, as long as 2.0 × 10exp6 of CD34+ cells per kg of body weight have been collected, poor mobilization was not associated with inferior engraftment. Disclosures: No relevant conflicts of interest to declare.

Background Six cycles of R-CHOP (rituximab plus cyclophosphamide, doxorubicin, vincristine, and prednisone) are the standard treatment for aggressive B-cell non-Hodgkin lymphoma. In the FLYER trial, we assessed whether four cycles of CHOP plus six applications of rituximab are non-inferior to six cycles of R-CHOP in a population of patients with B-cell non-Hodgkin lymphoma with favourable prognosis. Methods This two-arm, open-label, international, multicentre, prospective, randomised phase 3 non-inferiority trial was done at 138 clinical sites in Denmark, Israel, Italy, Norway, and Germany. We enrolled patients aged 18-60 years, with stage I-II disease, normal serum lactate dehydrogenase concentration, ECOG performance status 0-1, and without bulky disease (maximal tumour diameter <7•5 cm). Randomisation was computer-based and done centrally in a 1:1 ratio using the Pocock minimisation algorithm after stratification for centres, stage (I vs II), and extralymphatic sites (no vs yes). Patients were assigned to receive either six cycles of R-CHOP or four cycles of R-CHOP plus two doses of rituximab. CHOP comprised cyclophosphamide (750 mg/m²), doxorubicin (50 mg/m²), and vincristine (1•4 mg/m², with a maximum total dose of 2 mg), all administered intravenously on day 1, plus oral prednisone or prednisolone at the discretion of the investigator (100 mg) administered on days 1-5. Rituximab was given at a dose of 375 mg/m² of body surface area. Cycles were repeated every 21 days. No radiotherapy was planned except for testicular lymphoma treatment. The primary endpoint was progression-free survival after 3 years. The primary analysis was done in the intention-to-treat population. Safety was assessed in all patients who received at least one dose of assigned treatment. A non-inferiority margin of-5•5% was chosen. The trial, which is completed, was prospectively registered at ClinicalTrials.gov, NCT00278421.

In a previous systematic review and meta-analysis of five randomized controlled trials comparing rituximab maintenance with no maintenance (observation or rituximab at progression) for patients with follicular lymphoma, we reported that rituximab maintenance treatment improved the overall survival of patients. In this study, we did a similar search of the electronic databases updated through December 31, 2010, and included nine trials and 2586 follicular lymphoma patients. Hazard ratios (HRs) for time-to-event data were estimated and pooled using the inverse variance method. Risk ratios for dichotomous data were pooled using a fixed effect model. Patients treated with rituximab maintenance had improved overall survival (pooled HR of death = 0.76, 95% confidence interval [CI] = 0.62 to 0.92) compared with patients in the no maintenance group. Patients with refractory or relapsed (ie, previously treated) follicular lymphoma treated with rituximab maintenance had improved overall survival (pooled HR of death = 0.72, 95% CI = 0.57 to 0.91), whereas previously untreated patients had no survival benefit (pooled HR of death = 0.86, 95% CI = 0.60 to 1.25). The rate of infection-related adverse events was higher in the rituximab maintenance group (pooled risk ratio = 1.67, 95% CI = 1.40 to 2.00). These results further support the use of rituximab maintenance in the standard of care for refractory or relapsed follicular lymphoma.