Carter, Shelly L.

Abstract Abstract 2877 FLC assay measures circulating unbound k and l light chains and is of diagnostic and prognostic value in plasma cell disorders. Normalization of FLC ratio is considered a higher level of complete response (CR) in MM but this has not been well validated prospectively. HLC is a novel antibody based assay that targets the unique junctional epitopes between the heavy chain and light chain constant regions of intact immunoglobulin (Ig) molecules. It separately measures in pairs the light chain types of each immunoglobulin class generating ratios of monoclonal Ig/background polyclonal Ig concentrations (i.e IgGκ/IgGλ, IgAκ/IgAλ and IgMκ/IgMλ); potentially simplifying assessment of monoclonal protein response. To assess the prognostic impact of these assays and to correlate them with electrophoretic/immunofixation (SPE/IFE) assessment, we analyzed 497 stored serum samples from patients enrolled in the Blood and Marrow Transplant Clinical Trials Network (BMT CTN) 0102 clinical trial, sponsored by the NHLBI and NCI, of tandem autologous (autoHCT) vs. tandem autoHCT- allogeneic (alloHCT). Samples were collected prior to the first autoHCT and analyzed for FLC (Freelite™) and HLC (Hevylite™) at The Binding Site, UK. Corresponding disease status determination was centrally performed by an expert data review committee using uniform response criteria and correlated with FLC and HLC results. HLC remission was defined as normalization of composite heavy and light chain ratios across all 3 measured heavy/light chain pairs or the normalization of clonal isotype with normal ratios of uninvolved pairs. The demographics of 497 patients with HLC/FLC samples at baseline were concordant with the main study and showed similar patient proportions from the 2 study arms. Of the 211 pts with baseline SPE response better than or equal to a very good partial response (>VGPR), 188 also had an HLC remission (Sensitivity=89%). Comparison of the HLC remission with the >VGPR disease state also identified a specificity of 52%, positive predictive value (PPV) of 58% and a negative predictive value (NPV) of 87%. Similarly, all 56 patients in complete remission (CR) by SPE/IFE were in HLC remission. Compared with conventional CR assessment, sensitivity of HLC remission was 100%, specificity 39%, PPV and NPV values of 17% and 100% respectively. FLC remission correlated with >VGPR disease state had a sensitivity of 47%, specificity of 81% and a PPV and NPV of 64% and 67% respectively. Multivariate models for post transplant progression free survival (PFS) indicated that baseline disease response (>VGPR vs. partial remission (PR) or<PR) was associated with longer PFS. Adjusted models including baseline response, myeloma stage and study arm were used to compare the predictive utility of HLC and FLC assays. There was a lower risk of treatment failure (HR 0.74, p=0.02) and superior PFS for patients who achieved an HLC remission. When stratified by baseline disease response states, there was no additional prognostic impact for HLC remissions on PFS. Normalization of FLC ratio among patients with >VGPR disease state did not impact PFS (HR 0.96, p=0.83). Abnormal HLC after induction therapy has a high negative predictive value (100%) for identifying patients not achieving CR by uniform response criteria and is also associated with shorter PFS after transplant. FLC ratio normalization had no impact suggesting that stringent CR criteria may need further validation. Disclosures: Krishnan: Celgene: Speakers Bureau; Millenium: Speakers Bureau. Alvi:the binding site: Employment. Harding:The Binding Site Group Ltd: Employment. Maloney:Cellgene: Consultancy.

Abstract Abstract 3009FN2 Objective: To determine toxicity and efficacy of adding fludarabine (FLU) to a regimen of total body irradiation (TBI), anti-thymocyte globulin (ATG) and cyclophosphamide (CY), with de-escalation of the CY dose. The goal is to minimize CY-related toxicities while preserving (or improving) engraftment and survival in patients with SAA receiving an unrelated donor marrow transplant. Patients and Methods: Since May 2006, the Blood and Marrow Transplant Clinical Trials Network (BMT CTN), sponsored by the NHLBI and NCI, has conducted a prospective Phase I/II clinical trial of unrelated donor marrow transplantation in SAA (BMT CTN 0301). Patients with SAA are eligible if they are < 65 years, have adequate organ function, and have an available unrelated marrow donor matched 7 of 8 HLA-A, B, C, DRB1 loci. Patients with Fanconi anemia and other marrow failure syndromes are excluded. All patients receive TBI 200 cGy, ATG (either thymoglobulin: 3 mg/kg IV or ATGAM 30 mg/kg IV daily × 3, days –4 to –2), FLU (30 mg/m2 IV daily × 4, days –5 to –2). The Phase I portion of the trial sequentially tested four CY dose levels: 150 mg/kg (administered days –4 to –2); 100 mg/kg (days –3 to –2); 50 mg/kg (day –2); and, 0 mg/kg, and allowed enrollment of up to six patients at each CY dose level unless toxicity or graft failure boundaries were crossed. In the Phase II portion of the trial, patients enroll onto the optimal CY dose level, which is chosen using adaptive Bayesian criteria to rank desirability of the CY doses. All patients are followed for two years after transplantation. Early stopping guidelines are used to monitor for graft failure and early transplant-related mortality through day 100. Results: Twenty-one patients accrued to the Phase I portion of the trial. CY dose level 0 mg/kg was closed after all three enrolled patients developed secondary graft failure. All received a second allograft. One patient remains alive at 23 months after the first transplantation. The other two died from adult respiratory distress syndrome (ARDS) at 114 days after the first transplant and idiopathic pneumonia at 200 days after the first transplant. Review of Phase I results for the other three dose levels suggested CY dose 150 mg/kg as the optimal dose level for Phase II testing. However, after an additional eight patients were treated at this dose, the level was closed to further accrual because of excess toxicity. Seven of the 14 patients receiving 150 mg/kg of CY (and 7 of the last 8 enrolled) died. Causes of death were cardiac/pulmonary/multi-organ failure (n=4), ARDS (n=2), and parainfluenza virus type 3 pneumonia (n=1). Bayesian evaluation of the two remaining dose levels indicates very similar desirability scores and accrual continues at both the CY 100 mg/kg and 50 mg/kg levels. As of July 15, 2011, a total of 61 patients have been enrolled, 17 on the two closed levels, 33 on the 100 mg/kg level and 11 on the 50 mg/kg level. Conclusions: Early analysis of this trial, made necessary by these unexpected severe adverse events, revealed two important findings among patients receiving low-dose TBI, ATG, and FLU at the doses outlined: 1) CY dose 0 mg/kg is associated with higher than expected graft failure; and, 2) CY dose 150 mg/kg is associated with excess transplant-related toxicity. Neither CY dose level should be tested further in the context of the regimen used in this trial. To date, the two intermediate CY dose levels (100 mg/kg and 50 mg/kg) have not crossed the graft failure or fatality stopping boundaries and accrual is in progress. Disclosures: Pulsipher: Genzyme: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 230 The prognosis for patients (pts) with acute myeloid leukemia (AML) who are aged 60 years or older at the time of initial diagnosis is poor. Even for pts achieving a first complete remission (CR1), prospects for long-term survival are poor due to the very high risk of relapse. Conventional myeloablative conditioning followed by allogeneic blood or marrow transplantation is associated with significantly less relapse compared with conventional chemotherapy when performed in younger pts with AML in CR1. However, the toxicity of this approach in older pts is prohibitive. A reduced intensity conditioning (RIC) regimen may mitigate the risk of early toxicity and while early results in older AML pts have been encouraging and suggest disease free survival (DFS) rates above 30% at 3 yrs (Farag et al, Biol Blood Marrow Transplant 2011), most data are retrospective and pts have not been treated uniformly. We therefore sought to determine the effectiveness of a uniform RIC regimen given to older pts with AML in CR1 on a prospective multi-center phase II trial conducted by the Alliance (formerly Cancer and Leukemia Group B (CALGB)) and the Blood and Marrow Transplant Clinical Trials Network (BMT CTN). The study, activated in 2004, was initially limited to recipients of a matched related donor (MRD) graft but was amended in 2006 to include matched unrelated donor grafts (URD). The primary endpoint of the study was 2-year DFS. We hypothesized that DFS at 2-years would exceed 20% and powered the study to detect a 2-year DFS probability of 35% for URD recipients. We focused the primary analysis on URD recipients since the majority of older pts require an URD graft. Eligible pts were from 60–74 years old inclusive, had AML in CR1 following induction chemotherapy, availability of a 6/6 MRD or 8/8 URD, and absence of significant end-organ damage prior to transplantation. Adverse events (AE) were initially recorded according to NCI-CTCAE v3.0, amended to v4.0 in 10/2010. Accrual was completed in 12/2011. 132 pts were registered at 21 centers and 123 transplanted (MRD (47%); URD (53%). All donor grafts were mobilized and collected following G-CSF (PBSC). The median age of pts was 65 (range 60–74) and 76 pts (62%) were male. At diagnosis, 67% had an intermediate risk karyotype, 20% adverse risk, <1% favorable, and in 11% data were missing. More than 90% achieved CR following standard “7+3” based induction. CR1 was achieved after 1 (59%) or 2 (41%) induction cycles. Consolidation therapy was administered for one (50%) or two (24%) cycles and 17% received no consolidation with data missing in 9%. All but the initial 8 MRD recipients (who received fludarabine and busulfan alone) were conditioned with the same regimen containing fludarabine (30mg/m2/day × 5), busulfan (6.4mg/kg IV total dose), and antithymocyte globulin (ATG; thymoglobulin) (7.5mg/kg total dose). Only one case of primary graft failure was reported. With a median follow-up of 3.3 yrs, the results in the 123 transplanted pts are depicted below: Event Cumulative incidence at 100 days* or 2yrs† 95% CI Acute GVHD 2-4 9.4%* 4.1–15% Acute GVHD 3-4 3.4%* 1.2–6.7% Chronic GVHD 26%† 17–34% Relapse 47%† 37–57% Treatment related mortality (TRM) 14%† 7.2–21% Event Probability at 2 yrs 95% CI DFS 39% 30–50% DFS URD only 38% 26–55% Overall survival (all pts) 46% 36–57% The rates of both acute and chronic GVHD as well as TRM were relatively low. There were 81 grade 3–5 non-hematologic AE recorded, including 7 grade 5 (4 infections, 1 each cardiac, pulmonary, and second malignancy). Relapse was the most common cause of death. In conclusion, the results of this first prospective US cooperative group trial conducted in a homogeneously treated group of older AML patients in CR1 demonstrate the feasibility and effectiveness of RIC allografting using MRD or URD PBSC grafts. DFS appears better following a RIC allograft compared to results achieved historically after conventional therapies, warranting prospective comparison in pts with contemporary cytogenetic and molecular disease characterization. Future research should also focus on preventing disease relapse after RIC allografting in this population. Disclosures: Devine: Sanofi: Honoraria, Research Funding. Off Label Use: Antithymocyte globulin for GVHD prophylaxis is included in the abstract. Vij:Millennium: Speakers Bureau. Shea:Otsuka: Research Funding.

Abstract Abstract 739 The combination of a calcineurin inhibitor and methotrexate has been the standard of care in graft-vs.-host disease (GVHD) prophylaxis for over 25 years, with resultant rates of grade II-IV acute GVHD between 30–50%. The mTOR inhibitor, sirolimus, has demonstrated promise in a number of Phase II trials as an immunosuppressant used for GVHD prophylaxis. The BMT CTN, sponsored by the NHLBI and NCI, conducted a multicenter, randomized controlled trial comparing the combination of tacrolimus and sirolimus (Tac/Sir) with tacrolimus and methotrexate (Tac/Mtx) as GVHD prophylaxis after matched, related donor (MRD) hematopoietic stem cell transplantation (HSCT). Methods: Eligible patients were between ages 2 – 60 years, and had acute leukemia in remission, myelodysplasia or chronic myeloid leukemia in chronic or accelerated phase. All had adequate organ function, and a 6/6 HLA-A, B, DRB1 matched sibling donor. 304 patients were randomly assigned to either Tac/Sir (n = 151) or Tac/Mtx (n = 153) as GVHD prophylaxis after TBI-based conditioning and MRD HSCT. An intent-to-treat analysis was performed on the primary endpoint of Grade II-IV GVHD-free survival 114 days from randomization. Ten subjects who received busulfan-based conditioning and were previously reported were excluded from analysis. Three subjects who did not undergo HSCT are included in the primary analysis, but not secondary analyses. Results: Treatment groups were well balanced. The median age of participants was 44 years (range 13 – 59) and 83% had acute leukemia. Neutrophil and platelet engraftment were both faster in the Tac/Sir group (14 vs. 16 days, p < 0.001; 16 vs. 19 days, p = 0.03, respectively), but this did not affect the time to first hospital discharge (20 vs. 21 days, p = 0.37). The incidence of grade II-IV and grade III-IV acute GVHD at 100 days were lower in the Tac/Sir group (26 vs. 34%, p = 0.17; 8 vs. 15%, p = 0.05). Day 100 treatment-related mortality was no different between groups (7 vs. 7%, p = 0.43). The primary endpoint of 114-day acute GVHD-free survival was not statistically different between groups (67 vs. 62%, p = 0.38, Figure). The cumulative incidence of relapse at 2 years from transplantation was not different between groups (27 vs. 30%, p = 0.81). The competing-risk cumulative incidence of chronic GVHD was higher in the Tac/Sir arm (54 vs. 43%, p =0.044). Overall toxicities were not different between groups, with two notable exceptions. The peak and average OMAS oral mucositis scores were lower in the Tac/Sir arm (peak 0.70 vs. 0.96, p < 0.001; average 0.31 vs. 0.47, p < 0.001), however, there was an increased rate of the endothelial injury syndromes, veno-occlusive disease (11 vs. 4%, p = 0.03), and thrombotic microangiopathy (5 vs. 1%, p = 0.05) in the Tac/Sir arm. Causes of death were not different between groups. At 2 years from transplantation, disease-free (DFS) and overall survival (OS) were not different between study arms (DFS 53 vs. 53%, p = 0.76; OS 60 vs. 61%, p = 0.44). Conclusions: No difference in 114-day acute GVHD-free survival was noted between treatment arms. Compared with Tac/Mtx in MRD HSCT, Tac/Sir is associated with more rapid engraftment, less severe acute GVHD and oral mucositis, excess chronic GVHD and endothelial injury syndromes, and similar long-term outcomes. Understanding the trade-offs between regimens, Tac/Sir can be used as an alternative to Tac/Mtx in MRD HSCT. Disclosures: Cutler: Pfizer, inc: Research Funding; Astellas, Inc: Consultancy, Research Funding. Off Label Use: Sirolimus - Prevention of GVHD Tacrolimus - Prevention of GVHD. Waller:Outsuka: Research Funding.

Key Points Tac/Sir prophylaxis provides equivalent GVHD-free survival when compared with Tac/Mtx in MRD transplantation. Tac/Sir is associated with more rapid engraftment and reduced oropharyngeal mucositis after MRD transplantation.