Micallef, Ivana N.

Abstract Introduction: We previously reported that plerixafor + G-CSF was as safe as and more effective than placebo + G-CSF in mobilizing hematopoietic stem cell for autologous transplant in patients with multiple myeloma (MM) through 100 days follow-up (DiPersio ASH 2007). We report herein the 12 months data. Methods: This is a phase 3, multi-center, randomized (1:1), double-blind, placebocontrolled study. Multiple myeloma patients requiring an autologous hematopoietic stem cell transplant, in first or second complete or partial remission were eligible. Patients received G-CSF (10μg/kg/day) subcutaneously for up to 8 days. Beginning on evening of Day 4 and continuing daily for up to 4 days, patients received either plerixafor (240μg/kg) or placebo subcutaneously. Starting on Day 5, patients began daily apheresis for up to 4 days or until ≥ 6 x 106 CD34+cells/kg were collected. We report herein the 12 months graft durability and hematology data. Results: As reported previously, the primary endpoint of collecting ≥ 6 x 106 CD34+ cells/kg in ≤ 2 days of apheresis was met in 106/148 (71.6%) patients in the plerixafor group and 53/154 (34.4%) patients in the placebo group, p<0.001. 142 (96%) patients in plerixafor group and 136 (88%) patients in placebo group underwent transplantation. Median time to PMN and PLT engraftment was similar in both groups. Through 12 months follow-up, there were no differences in graft durability and hematology profiles between groups (Table 1). Over the 12 months, 6/142 (4.2%) patients in the plerixafor group and 5/136 (3.7%) patients in the placebo group died. Of the patients who died, 2 patients in the plerixafor group and 2 patients in the placebo grouped died due to disease progression. Plerixafor + G-CSF Placebo + G-CSF Hematology data presented as mean ± SD and n=number of patients with available data P values were NS for all variables at all time points between groups aAll patients who underwent transplantation bAll patients who underwent transplantation and had laboratory data at the study visit Graft durability (n, %) 100 daysa 140/142 (98.6%) 133/136 (97.8%) 6 monthsb 133/135 (98.5%) 125/127 (98.4%) 12 monthsb 127/128 (99.2%) 119/120 (99.2%) Platelet (x 109/L) 100 days 226 ± 80 (n=90) 210 ± 88 (n=87) 6 months 218 ± 67 (n=95) 209 ± 89 (n=93) 12 months 204 ± 69 (n=53) 205 ± 80 (n=54) Neutrophils (x 109/L) 100 days 3.3 ± 2.3 (n=88) 3.0 ± 1.7 (n=80) 6 months 3.4 ± 1.6 (n=90) 3.5 ± 1.8 (n=88) 12 months 3.1 ± 1.1 (n=52) 3.6 ± 2.1 (n=52) Hemoglobin (mg/dL) 100 days 12.5 ± 1.5 (n=89) 12.6 ± 1.3 (n=86) 6 months 12.7 ± 1.4 (n=94) 12.7 ± 1.6 (n=92) 12 months 12.9 ± 1.8 (n=53) 13.1 ± 1.5 (n=54) Conclusions: The addition of plerixafor to G-CSF resulted in higher CD34+ cell collection in fewer days of apheresis than G-CSF alone. Importantly, this 12 months report showed that transplants with cells collected with plerixafor resulted in graft durability rates that were similar to cells collected with G-CSF alone.

Abstract The peripheral blood absolute lymphocyte count (ALC) on day 15 after autologous stem cell transplantation (ASCT) has been shown to be an independent predictor for overall survival (OS) for many malignancies including acute myelogenous leukemia (AML), breast cancer, multiple myeloma (MM), primary systemic amyloidosis, and Hodgkin’s and non-Hodgkin’s lymphoma (NHL). A recent report (Dean et al. BMT2005; 36, 1049–1052) suggested that infused autograft dendritic cells (DC) affect survival post-ASCT in NHL. Thus, DC recovery at day 15 post-ASCT was assessed and correlated with OS. Preliminary data from an ongoing prospective study of 28 NHL patients post-ASCT are reported. Absolute DC at day 15 was analyzed by four color flow cytometry using antibodies to CD3, CD14, CD16, and CD19. In this approach lymphocytes and DCs were initially gated by their similar forward and side light scatter characteristics; DCs were then identified as cells in this gate that lacked staining for the lymphocyte antigens CD3, CD16, and CD19 and the monocyte antigen CD14. The percentage of antigen negative cells cells in the lymphocyte gate was then multiplied by the coincident peripheral blood absolute lymphocyte to determine the absolute DC count. Survival was then analyzed using the Kaplan-Meier method. With a median follow-up of 18 months, patients recovering a DC of 10 cells/μl or above experienced superior median OS versus those who did not (not reached vs 21 months, p < 0.02, Figure 1). This study shows that an immunocompetent immune system at day 15 (not only ALC recovery, but also DC recovery) correlates with survival in NHL patients undergoing ASCT. Figure Figure

Abstract Abstract 85 Background: Follicular lymphoma (FL) is an indolent non-Hodgkin lymphoma (NHL) with a highly variable natural history. Clinical variables describing either patient- or tumor-specific characteristics, many of which are included in the Follicular Lymphoma International Prognostic Index (FLIPI), are used to risk-stratify patients at the time of diagnosis. However, characteristics of non-malignant cells present within the tumor microenvironment provide important prognostic information. For example, both immunohistochemistry and gene expression profiling studies demonstrate that lymphoma-associated macrophages (LAMs) are prognostically important in FL. As LAMs are monocyte-derived, we sought to determine whether the absolute monocyte count (AMC) obtained from a CBC at diagnosis is an adverse prognostic factor in FL. Methods: Consecutive patients with FL who were evaluated and treated at the Mayo Clinic, Rochester between 1998 and 2007 were considered for study participation. Study approval was granted by the Mayo Clinic Institutional Review Board. The primary objective of the study was to determine the significance of the AMC, obtained at the time of diagnosis from a standard complete blood count with differential, in predicting overall survival. The secondary study objective was to determine whether the AMC is an independently significant prognostic factor when compared with the FLIPI. Results: The median follow-up was 4.2 years (range: 2 months to 11 years) for the 355 patients included in this study. At diagnosis, 43%, 34% and approximately 23% of patients were classified as low-, intermediate- or high-risk by the FLIPI. The median AMC at diagnosis was 510/μL, with 8% of patients presenting with an absolute monocytosis. At diagnosis, 45% of patients were initially observed, 42% received combination chemotherapy or immunochemotherapy alone, while the remaining 13% underwent surgery or radiation. The AMC was evaluated as both a continuous and dichotomized variable on univariate analysis. The optimal cut-point for the AMC was determined to be 570/μL by ROC analysis and was used when analyzing the AMC as a dichotomized variable. A relative elevation in the AMC was associated with inferior overall survival, whether analyzed as a continuous or dichotomized variable, with hazard ratios (HR) of 1.002 (HR per unit change in AMC; 95% confidence interval 1.001–1.002; p=0.0002) and 3.4 (95% confidence interval 2.0–6.0; p<0.0001), respectively. The median OS for patients with an AMC <570/μL at diagnosis has not been reached, whereas a median OS of 10.2 years (95% confidence interval 7.8–11.2 years; p<0.0001) was observed for those patients with an AMC ≥570/μL. For comparison, median OS has not been reached for high-risk patients identified by the FLIPI. Among those patients who were initially observed, the median time to progression (TTP) was 31 months (95% confidence interval 25–37 months) for those with an AMC <570/μL at diagnosis. In contrast, patients with an AMC ≥570/μL experienced a significantly shorter TTP following initial observation, with a median TTP of 18 months (95% confidence interval 8–28 months; p=0.03). When adjusting for prognostic factors included in the FLIPI on multivariate analysis, the association between the AMC as a dichotomized variable and survival remained significant with a HR of 2.6 (95% confidence interval 1.5–4.6; p=0.001). When the FLIPI alone (high vs. low/intermediate) was analyzed on multivariate analysis, the AMC remained an independent predictor of survival (p<0.0001). Furthermore, the AMC provided additional prognostic information when superimposed upon the FLIPI. For example, a subset of patients classified as high-risk by the FLIPI were observed to have an OS comparable to low/intermediate risk patients identified by the FLIPI upon further risk-stratification by the AMC, with a 6-year OS of 80%. In contrast, high-risk FLIPI patients with an AMC ≥570/uL were observed to have a median OS of 4.2 years (95% confidence interval 2.7–7.2) and 6-year OS of 47%. Conclusions: The AMC is associated with overall survival in FL and is independent from the FLIPI on multivariate analysis. While the AMC did not appear inferior to the FLIPI in identifying high-risk patients, it may be most helpful when used in conjunction with the FLIPI. These results further support the central role of nonneoplastic myeloid-lineage cells in FL biology. Disclosures: No relevant conflicts of interest to declare.

Abstract Abstract 3095 Background: Although HDM is the standard conditioning for pts with MM undergoing ASCT, it is not sufficient for cure. In an effort to improve upon this standard, we added escalating doses of Y-90 Zevalin (a murine IgG1 kappa monoclonal antibody Ibritumomab conjugated to Y-90) to HDM in a standard 3+3 phase I trial design. Y-90 is a beta-emitting radioisotope with a path length of 5 mm allowing it to target CD20+ cells and bystander cells within 5 mm. Methods: Eligibility included being a candidate for ASCT. Consenting patients (pts) received: day -22, rituximab 250 mg/m2 with In2B8 for scanning; day -14, rituximab 250 mg/m2 with escalating doses of Y90-Zevalin; day -2 and -1, melphalan 100 mg/m2/day; day 0, at least 2 × 10(6) CD34/kg stem cells; and GM-CSF until ANC engraftment. The 6 dose levels (DL) were (in Gy): 10; 12; 14; 16; 18; and 20. Dose limiting toxicity (DLT) was defined as: sustained pulmonary or liver toxicity (grade3; 96 hours duration or VOD that does not resove by day 30); delayed engraftment (ANC < 500 at day 21 or platelet transfusion dependence at day 35); and non-hematologic grade (gr) 4 toxicity excluding gastrointestinal or constitutional. Responses were according to IMWG criteria. Accrual was between May 2005 and June 2011. Data was frozen as of August 2, 2011. Results: Thirty pts have been accrued: DL1, 3; DL2, 3; DL3, 3; DL4, 6, DL5, 6; DL6, 6. The median age of patients was 59 (range 32, 73), and 70% were male. 60% had ASCT as primary therapy. The other patients were transplanted in chemosensitive relapse (n=3), chemoresistant relapse (n=7), and untested relapse (n=2). Median time from diagnosis to protocol therapy was 10.4 months (range 3.5, 94.3). Five pts had prior radiation therapy, and 11 had prior ASCT. Maximum tolerated dose (MTD) of Zevalin with fixed dose melphalan 200 mg/m2 was DL 5 (18 Gy) which amounted to 168 mCi (124, 182) administered. No DLTs were observed at DL 1, 2, 3, or 5. There was 1 DLT at DL 4, comprising hepatic failure (gr 5) CMV viremia (gr 3), and delayed engraftment, in a 73 yo patient with chemoresistant relapsed disease, and 2 DLTs at DL 6. These DL 6 DLTs included: 1) fatal bowel necrosis (day 12 post ASCT) in a 67 yo patient with relapsed refractory MM and history of CAD, ischemic colitis, DM; and 2) fatal biopsy proven venoocclusive disease (gr 5), which began day 91 post ASCT in a 62 yo patient with primary refractory MM, peri-mobilization S. aureus bacteremia with septic embolic, and line associated venous thrombosis. Overall, gr 3 or higher AEs were observed in 100% of pts. Non-heme gr 4 AEs were seen in: DL1, 1; DL2, 2; DL3, 0; DL4, 1; DL5, 0; DL6, 4. Median time to ANC >=500 and plts>=50 was 11 (range 8, 17) and 15 days (range 11, 89). Confirmed response rates from immediately pre-protocol to best confirmed response were: CR, 5; VGPR, 5; continued VGPR, 4, and continued PR, 7. If one includes best confirmed response from baseline for those patients using transplant as primary consolidation, 4 PRs are upstaged to VGPRs. Median follow-up for all pts is 24.5 months (0.8, 64.8), and 10 pts have died. The median PFS for pts proceeding to early and delayed ASCT was 30.4 months (95%CI 4.1-NR) and 10.3 months (95%CI 2.8–21.7), respectively. The median OS for pts proceeding to early and delayed ASCT was not attained and 11.4 months (95%CI 2.8-NA), respectively. Conclusions: For patients with multiple myeloma, the MTD of Zevalin with fixed high-dose melphalan is 18 Gy. The combination of a VGPR plus continued VGPR rate of 60%, a median PFS of 13.1 months, and a 73% 1 year OS rate make this a regimen worthy of further study. Disclosures: Kumar: Merck: Consultancy, Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 4228 Background Peripheral blood stem cells (PBSC) are the preferred graft type for autologous stem cell transplantation (ASCT) and mobilization is typically done using growth factor (GF) alone or a combination of chemotherapy (CTX) and GF. The success of mobilization is influenced by several factors such as prior therapy, mobilization strategy, underlying disease, among others. Patients (Pts) failing to mobilize successfully often have GF dose increased and if unsuccessful, mobilization is reattempted with chemotherapy + GF or G-CSF (Granulocyte Colony-Stimulating factor) + GM-CSF (Granulocyte–Macrophage Colony-Stimulating factor). More recently, plerixafor, a CXCR4 inhibitor, has been found to enhance G-CSF based collection allowing potential early intervention in poor mobilizers. However, this approach requires valid cut-points for peripheral CD34 counts (pCD34) for cost efficient use. Methods We studied 656 first time, G-CSF based PBSC mobilizers with Non-Hodgkin Lymphoma (562; 86%), or Hodgkin's Disease (94; 14%). Salvage attempts were excluded, as were first attempts using CTX+GCSF, plerixafor or GF combinations. Sensitivity-specificity analysis (Receiver operating characteristic) was used to define ideal cut-points for predefined outcomes. We used a CD34 yield of 2 million/kg as the minimum required collection and 5 million/kg as the ideal collection for the current analysis. Our current practice is to initiate collection at a pCD34 of 10/uL. Results We first determined the best day 1 pCD34 cutoff for being able to collect at least 2 million/kg PBSC to be 9/uL. Among those with ≥9/uL, only 6.6 % failed to collect at least 2 million compared to 55% among the rest (P < 0.001). These numbers were 6.3% and 50% respectively using the traditional cutoff of 10/uL. We then examined how the pCD34 on day 2 predicted collection, among those failing to reach the current threshold of 10/uL. Among this group, a pCD34 on day 2 of 9.1/uL was the best cutoff to predict a collection of 2 million/kg. Among those with >=9.1/uL, only 22% failed to collect at least 2 million compared to 79% among the rest (P < 0.001). Among those with day 1 pCD34 < 10, 49% achieved a count of 9.1/uL on day 2. We then examined what pCD34 on day 1 can best predict a pCD34 ≥ 9.1 on day 2 and found this to be 5.2/uL. Among those with day 1 pCD34 ≥ 5.2/uL, 79% reached day 2 pCD34 ≥ 9.1 compared to 24% among the rest (P < 0.001). We then determined cutoffs based on ideal targets using only those patients achieving pCD34 count > 10/uL by day 2, since these patients would have started collection without any change in the mobilization technique. We used a maximum of 5 collections to achieve the goal as being ideal, taking into account the most commonly used practice of collecting during weekdays. We examined cutoffs for a target of 5 million/kg for one transplant. The best day 1 or day 2 pCD34 predicting a 5 million/kg yield in 5 collections was 17/uL. Among those with day 1or 2 pCD34 ≥ 17/uL, 4% failed to reach 5 million in ≤ 5 days compared to 96% among the rest (P < 0.001). Conclusions This study provides an estimate of optimal pCD34 count thresholds for early identification of patients with lymphoma at high risk of collection failure. It is reasonable to use the first or second day pCD34 count, since a substantial proportion of patients will achieve the threshold value by day 2 and these patients appear to have similar outcome as those reaching the threshold by day 1. Based on the results here, interventions such as addition of plerixafor can be considered if pCD34 count is < 6/uL on day 1 or < 10/uL by day 2, to achieve the minimum collection of 2 million/kg. However, in order to achieve the ideal targets, a higher threshold should be considered and the recommendation based on the current study would be 17/uL for a target of 5 million. Such a target-adapted strategy may be more appropriate. Disclosures: Kumar: Celgene,Genzyme,Millenium,Novartis,Bayer,: Honoraria, Research Funding. Gertz:Genzyme: Research Funding. Micallef:Genzyme: Research Funding.

Abstract Peripheral blood infused total autograft absolute lymphocyte count (A-ALC) correlates with day 15 absolute lymphocyte count and is an independent prognostic factor for survival after autologous stem cell transplantation (ASCT) for non-Hodgkin lymphoma (NHL). Factors to enhance A-ALC collections are not well defined. We hypothesize that the number of peripheral blood apheresis collections (PBAC) directly correlates with A-ALC. 190 consecutive NHL patients who underwent ASCT at the Mayo Clinic between 1993 and 2001 were analyzed. The primary end point of the study was to assess the correlation between the number of PBAC and A-ALC. The secondary end point was to determine if the number of PBAC affected survival post-ASCT. Of the 190 patients, 18 patients underwent 1 PBAC, 23 patients 2 PBAC, 50 patients 3 PBAC, 37 patients 4 PBAC, 50 patients 5 PBAC, and 12 patients had ≥ 6 PBAC. There was no association between the number of PBAC and the number of CD34+ stem cells collected (p= 0.25). A strong association between number of PBAC and A-ALC (Kruskall Wallis test, p <0.0001)(Figure 1) was identified. Using a cut-off of 4 PBAC, superior overall survival (OS) and progression-free survival (PFS) were observed for patients that underwent 4 PBAC or more compared to patients that underwent less than 4 PBAC (86 months vs 18 months, p <0.0001; 76 months vs 10 months, p <0.0001, respectively). Multivariate analysis demonstrated PBAC ≥ 4 is an independent prognostic factor for OS (RR = 0.654, 95%CI: 0.529–0.804, p< 0.0001) and for PFS (RR = 0.682, 95%CI: 0.561–0.826, p< 0.0001) when compared with other significant factors including performance status, lactate dehydrogenase and extra nodal disease. These data suggest that increasing the number of PBAC beyond the minimum number required to meet CD34+ collection targets may result in improved overall and progression-free survival mediated by an increase in autograft absolute lymphocyte count.

Abstract Abstract 4359 Routine serial chimerism analysis after allogeneic stem cell transplantation (Allo-SCT) has been used as a risk factor for post-Allo-SCT cancer relapse. In non-Hodgkin lymphoma (NHL) patients treated with autologous peripheral blood hematopoietic stem cell transplantation (APHSCT), a specific predictor during routine follow-up that could be used to ascertain risk for post-APHSCT relapse has not been identified. Thus, we set out to investigate if absolute lymphocyte count (ALC) measured at post APHSCT follow-up could serve as a marker of post-APHSCT NHL relapse. ALC was obtained at the time of confirmed relapse at follow-up and at last no evidence of relapse follow-up. From 1993 until 2005, 269 patients treated with APHSCT for diffuse large B-cell lymphoma (DLBCL), were included in this study. Patients at last follow-up with no relapse (N=137) had a higher ALC compared with those with confirmed relapsed at follow-up post-APHSCT (N= 132) [median ALC x 109/L of 1.66 (range: 0.13-3.69) vs 0.71 (range: 0.03-4.75), p <0.0001, respectively]. ALC at follow-up was a strong predictor for relapse with an area under the curve (AUC) = 0.86 (p<0.0001). An ALC of 1.0 × 109/L was identified as the optimal cut-off point. An ALC < 1.0 × 109/L at the time of confirmed relapse had a positive predictive value of 89% and a positive likelihood ratio of 8.4 to predict relapse post-APHSCT. Patients with an ALC ≥ 1.0 × 109/L (N = 147) had a cumulative incidence of relapse of 19% versus 92% for patients with an ALC < 1.0 × 109/L (N = 122) (p<0.0001) at follow-up post-APHSCT. This study suggests that ALC at follow-up can be used as a marker to assess risk of DLBCL relapse during routine follow-up after APHSCT. Disclosures: No relevant conflicts of interest to declare.

Abstract Purpose: Primary colorectal large B-cell lymphoma is rare and accounts for less than 1% of all malignancies in the colon. Standard treatment for limited stage diffuse large B-cell lymphomas (DLBCL) includes systemic therapy combined with involved field radiation therapy. However, radiation therapy may often not be feasible in patients with primary colon lymphoma. For primary DLBCL of the colon particularly the cecum, surgical resection prior to the administration of systemic chemotherapy has been considered to improve local control. The goal of this study was therefore to determine whether surgical resection improves the outcome of patients with primary DLBCL of the colon. Methods: Clinical information and outcomes on all the patients with primary DLBCL of the colon seen at Mayo Clinic, Rochester, between January 1980 and June 2005 were retrospectively reviewed. Results: There were 28 patients identified with primary colon DLBCL. Pre-existing conditions like colon polyps, Crohn’s disease and diverticulosis were uncommon. The most common presenting symptom was bleeding per rectum seen in 13 patients (46.5%). Other symptoms included abdominal pain, diarrhea and anemia. All patients had early stage disease (stage1–22 patients, stage2–6 patients) at diagnosis. Of the 28 patients, 16 underwent initial surgery followed by chemotherapy, 7 were treated with chemotherapy alone, and 5 patients had inadequate data to determine time to progression or overall survival. Chemotherapy was anthracycline based, with the most common regimen being CHOP (Cyclophosphamide, Doxorubicin, Vincristine, Prednisone). There was no difference in overall survival or time to progression between the 16 patients who received combined modality therapy compared to the 7 patients who received chemotherapy alone. Of the 16 patients who underwent surgical resection followed by chemotherapy, all 5 patients who relapsed, relapsed at other sites in the colon. Conclusion: Surgery as part of combined modality therapy did not appear to improve the outcome of patients with primary DLBCL of the colon. Systemic chemotherapy with an anthracycline-based regimen in combination with rituximab is therefore likely to be sufficient treatment for these patients. Follow-up for these patients should include a colonoscopy to monitor for recurrences at other sites in the colon.

Abstract Background: The phosphatidylinositol 3-kinase/mammalian target of rapamycin (mTOR) signal transduction pathway integrates signals from multiple receptor tyrosine kinases to control cell proliferation and survival. Everolimus (RAD001, Novartis Pharmaceuticals) is an oral investigational antineoplastic agent that targets mTOR. Objectives: To learn the anti-tumor activity and toxicity of single-agent RAD001 in pts with relapsed/refractory aggressive NHL. Patients and Methods: Patients were eligible if they had measurable disease, a platelet count >75,000, an absolute neutrophil count >1,000, and a creatinine and bilirubin <2x laboratory upper limit of normal. Patients received RAD001 10 mg PO daily and were evaluated monthly. Dose reductions to 5 mg daily and 5 mg every other day were allowed. Response was assessed after 2 cycles and periodically thereafter. Patients could remain on drug until progression or toxicity. Results: Thirty-seven pts were treated - 20 (54%) with relapsed diffuse large cell (DLC), 14 (38%) with relapsed mantle cell (MCL), 2 high grade, and 1 follicular grade III. The median age was 72 years (range, 45–92). Patients had received a median of 4 prior therapies (range, 1–15). The overall response rate was 32% (12/37; 95% CI:20–49%) with 1 complete response and 11 partial responses. The ORR was 35% (7/20) in the DLC group and 29% (4/14) in the MCL patients. Patients have received a median of 2 cycles (range, 1–16+) of therapy. The median time to progression for all 37 patients is 3.1 months (95%CI; 2.0 – 4.7). The median duration of response for the 12 responders is 5.5 months (95% CI; 2.3 – 9.2) and 5 pts remained progression free at 6 months. Three patients are currently maintaining a response with a median time of 10.5 months (range, 2.9–15.6+months). RAD001 was well tolerated. The incidence of grade 3 anemia, neutropenia, and thrombocytopenia in this heavily pretreated pt population was 11%, 16%, and 30%. Two pts developed grade 4 neutropenia. Grade 2 hypercholesterolemia occurred in 11%; grade 2 hyperglycemia in 16%; grade 3 hyperglycemia in 11% and 1 pt had grade 4 hypertriglyceridemia. Summary: RAD001 has single-agent activity in relapsed aggressive NHL and provides proof-of-concept that targeting the mTOR pathway in NHL is clinically relevant.

Background: High-dose chemotherapy and hematopoietic stem cell (HSC) transplantation is considered standard therapy in patients with chemosensitive relapsed diffuse large B cell lymphoma (DLBCL). BCNU, etoposide, cytarabine and melphalan (BEAM) is a standard widely used DLBCL conditioning regimen. Chemotherapy doses, both standard and high dose, are traditionally based in body surface area (BSA) and are often calculated using the corrected ideal body weight. However, this practice is empirical and the best way to dose chemotherapy is unknown. Weight-based dosing has been suggested to better predict toxicity of the conditioning regimen. We correlate the BEAM dose/actual weight ratio with toxicity and overall outcome in a uniform cohort of patients receiving HSC transplant for relapsed DLBCL Methods: Retrospective analysis of 80 consecutive patients treated at Mayo Clinic, Rochester, MN between 2001 and 2006 who received a HSC transplant following BEAM conditioning was performed. All doses were based on BSA calculated using the corrected ideal body weight. Weight-based dose intensity was retrospectively calculated utilizing the melphalan dose/Kg as a surrogate for the entire regimen. Weight-based dose intensity was correlated with toxicity in the first 30 days after transplant and survival outcome. Results: Median age at the time of transplant was 62 (interquartile range 53–65; range 26–77); 65% were males; median number of prior chemotherapy regimens was 2. Median dose of melphalan was 3.2 mg/Kg (interquartile range 2.9–3.6; range 2.2–4.5). Only one patient died within 30 days of the transplant. Patients who received > 3.6 mg/Kg of melphalan were more likely to have Grade 3 or 4 mucositis (44.4% v. 9.8%, P=0.001) than the remaining patients. Median numbers of days spent in the hospital in the first 30 days after transplant was 13 (3–18) for melphalan dose >3.6 mg/kg vs. 7 (0.5–10.5) for the remaining patients (P=0.043). Weight based dose intensity did not correlate with survival (P=0.8) or disease-free survival (P=0.3). Conclusion: Weight based dose intensity of BEAM correlates with toxicity post autologous HSC transplant. Patients receiving doses corresponding to >3.6 mg/kg of melphalan are at increased risk of high-grade mucositis and prolonged hospitalization. Figure Figure