Citations

Abstract Abstract 3047 Background: There is concern about the increased incidence of extramedullary plasmacytomas among patients with multiple myeloma (MM) in recent years (Varettoni et al Annals of Oncology 21: 325–330, 2010). There is controversy about whether novel agents increase the risk of extramedullary disease (EMD). EMD may be associated with decreased overall survival in MM. The purpose of this study was to determine the incidence of true, treatment-emergent EMD in MM among a cohort of patients who have been previously exposed to novel agent (thalidomide, lenalidomide, or bortezomib) therapy, and to evaluate the activity of pomalidomide in patients with EMD. Methods: We examined 174 consecutive patients with relapsed refractory multiple myeloma that were enrolled on a phase II clinical trial of pomalidomide plus low-dose dexamethasone. The study cohort was chosen since all patients had previously been exposed to novel agents, and were followed systematically. We adopted a strict definition of EMD which required that in order to be considered extramedullary, plasmacytomas must not have risen from any bone. Thus, masses arising from the bone with a soft tissue component were not considered extramedullary. Results: Of 174 patients studied, 16 patients (9.2%) had EMD prior to enrollment. In 3 of the 16 patients, EMD was present at time of diagnosis and was therefore not considered as treatment-emergent disease for this analysis. In 13 of 174 patients (7.5%) EMD developed during the course of MM, after starting therapy. All 13 patients by inclusion criteria were exposed to novel agents prior to the onset of EMD, including 100% to immunomodulatory agents (thalidomide or lenalidomide); and 78% (10 patients) were exposed to bortezomib prior to developing EMD. The median number of lines of prior therapy in these patients was 6, range 1–12). EMD occurred a median of 48 months following diagnosis (range, 16–183 months); the rate of EMD in the first 3 years following diagnosis of MM was 3%. Since all patients had prior exposure to immunomodulatory agents in this cohort, we were able to calculate the median length of time from initiation of immunomodulatory agents to onset of EMD as 24 months (range 7–119 months). The EMD sites involved included the temporal area soft tissue (3), muscle (3 [1 pt with 10 different areas of involvement, 1 pt with 5 muscles involved]), chest wall not attached to bone (3), abdominal/pelvic masses (3), kidney (2), scrotum (2), sinus (1), paraspinal (1), hilar/pleural based (1), paraesophageal (1), subcutaneous tissue (1), pancreas (1), spleen (1), mediastinum (1), pleural fluid (1), liver (1). Per protocol, all patients received pomalidomide (2-4 mg per day) and low dose dexamethasone (40 mg once a week). Of the 13 patients, there were 2 CR (with complete disappearance of EMD), 2 PR, 2 stable disease, 3 with progressive disease, and 4 patients who did not have their EMD re-evaluated. Thirty percent (n=4) of patients had a 50% or greater reduction in size of the EMD including one patient who received concomitant radiation. Overall survival from measured from trial entry was significantly shorter for patients who presented with EMD compared to those who did not have EMD, median 16 months versus not reached, p=0.002 (log-rank). Conclusion: We found that 7.5% of patients with relapsed refractory myeloma in the era of novel agents develop EMD during the course of their myeloma, including 3% within 3 years of diagnosis. The underlying reasons for the possible increased incidence of EMD may include better radiographic detection (the role of PET/CT scans and MRI), improved overall survival of patients in recent years, and the possibility that novel agents may increase the risk for strictly defined, true EMD among patients who did not have EMD at time of initial MM diagnosis. These need further study. Disclosures: Dispenzieri: Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Gertz:Celgene: Honoraria; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.

Abstract Abstract 2797 Poster Board II-773 Background: Primary systemic amyloidosis (AL) is characterized by deposition of light chain derived amyloid fibrils in multiple organs leading to varying degree of dysfunction. Cardiac involvement is a common feature of AL, and when significant is highly predictive of poor outcome. The currently used prognostic classification is based on cardiac biomarkers troponin-T (cTnT) and N-terminal pro B-type Natriuretic peptide (NT-ProBNP) and is effective at predicting outcome in patients with AL. However, this is driven primarily by the degree of cardiac involvement and does not take into account the degree of plasma cell burden and its impact on the disease course. It is possible that some of the heterogeneity in outcome can be explained by the plasma cell characteristics rather than the degree of the end organ damage. Methods: We examined the baseline clinical and laboratory data from 2119 patients with AL who were seen at our institution with in 90 days of their diagnosis. The data were collected from a prospectively maintained data base, and additional testing was done for free light chain levels (FLC) on stored sera from patients seen before the routine introduction of FLC testing. Cox proportional hazards analysis was performed to estimate the prognostic values of different variables. Results: We first examined the impact of plasma cell clone related characteristics namely, difference between involved and uninvolved FLC (FLC-Diff), bone marrow plasma cell (BMPC) %, plasma cell labeling index (PCLI), beta 2 microglobulin (B2M), and presence of circulating plasma cells, on overall survival (OS) from diagnosis. All variables were dichotomized into high and low based on their median value (FLC-diff: 20 mg/dL, BMPC: 10%, PCLI as a continuous variable, B2M: 3 mg/dL and circulating cells: absent or present). While all were found to be prognostic for OS in univariate analysis; in a multivariate analysis incorporating a stepwise selection only B2M and FLC-diff were significant. We then used these two variables along with the cTnT and NT-ProBNP that are used in the current model to develop a staging system. The median values for all four variables were used for developing the scores. Patients were assigned a score of 1 for presence of each characteristic (FLC difference > 20 mg/dL, troponin-T > 0.02, NT-ProBNP > 1000, and B2M > 3) or 0 if the value was at or below the cutoff. The scores were added to obtain a composite prognostic score that grouped the 370 patients (who had all the variables available for analysis) into 5 groups with very different OS (4.4, 9.3, 24.4, 43, and not reached for stages 4, 3, 2, 1, and 0 respectively; Figure A). However, since the NT-ProBNP did not have independent impact on survival in a multivariable model incorporating all the four variables, we also examined a system that only included FLC-diff, cTnT and B2M. This system again allowed grouping of patients (n=450 with all three variables available) into four distinct groups with divergent outcome with OS of 4.6, 10.5, 36.8, and not reached for stages 3, 2, 1, and 0 respectively; (Figure B). Conclusion: Incorporation of plasma cell related measurements into the existing staging system using cardiac biomarkers allows better risk stratification of patients with AL amyloidosis. The system using FLC, B2M and troponin has the advantage of easily available laboratory values and can be widely adopted. Addition of NT-ProBNP into the system allows better refinement of the intermediate risk groups. This system will allow upfront risk stratification and development of risk-adapted therapies for patients with AL. Disclosures: Gertz: Genzyme: Research Funding.

Abstract Abstract 1892 Background: Primary or light chain amyloidosis (AL) is a clonal plasma cell disorder characterized by a relatively low plasma cell burden and multi-organ deposition of immunoglobulin light chain derived amyloid fibrils. The survival of patients with amyloidosis is quite variable with median survival of 12–18 months in different series, and largely dependent on the number and severity of organs involved. In addition to new drugs, the combination of melphalan and dexamethasone is an effective regimen for AL and risk adapted approaches to SCT has decreased treatment related mortality. It is not clear if the recent progress in risk stratification and treatment approaches have translated into improved survival for these patients. Methods: We studied two separate cohorts of patients; the first cohort consisting of 2118 patients with AL seen at Mayo Clinic over a 40-year period between November 1967 and August 2006 was used to examine the trends in overall survival from diagnosis during this time period. The second cohort of 443 patients seen between September 2006 and August 2009 were examined only for the changes in early mortality and for validation of a model for predicting early mortality developed using the first cohort of patients. Results: The estimated median follow up for the entire group was 7.8 years (95% CI; 7.1, 8.5). The patients were divided into 4 cohorts based on date of diagnosis; 1966–1976 (n=121), 1977–1986 (n=343), 1987–1996 (n=636) and 1997–2006 (n=1017). The median OS from diagnosis for the four cohorts were 0.9, 1.2, 1.2 and 1.5 years respectively, P < 0.001 (Figure 1). More importantly there was steady improvement in the long-term survival among these patients with 4-year survival estimates of 16%, 21%, 24% and 33% respectively. Next, we specifically looked at the survival trends within the last cohort (1996-2006), dividing the patients into three time periods; 1996–1999 (n=263), 2000–2003 (n=291) and 2003–2006 (n=463). While the OS from diagnosis was relatively unchanged between the first and second time periods (28 vs. 30% 4 year survival), there was significant improvement in the last three year period (42% survival at 4 years); P =0.02. Given the high early mortality in this disease, we specifically examined the one-year mortality among the entire patient cohort and found no clear improvement in terms of one-year mortality. Using logistic regression analysis, we identified cTnT > 0.01, NT-ProBNP > 4200 and Uric Acid > 8.0 mg/dL to be the best predictors of death within one year of diagnosis. The probability of death within one year for those with none, 1, 2, and 3 risk factors was 19, 38, 61, and 78% respectively, P < 0.01 (Figure 2). This model was further validated among patients seen during the most recent three years, September 2006 and August 2009. Conclusion: Survival in AL amyloidosis has improved over time, particularly in the recent years and likely reflects the recent improvements in therapy. However, early mortality remains a problem and baseline factors can be used to identify patients at risk for early mortality, who then can be targeted for risk adapted therapy approaches in clinical trials. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding. Off Label Use: Lenalidomide for treatment of newly diagnosed myeloma. Dispenzieri:Celgene: Honoraria, Research Funding; Binding Site: Honoraria.

Abstract Abstract 1964 Background: Thalidomide (thal), lenalidomide (len) and pomalidomide (pom) have been shown to have considerable efficacy in patients with newly diagnosed as well as relapsed multiple myeloma (MM). They are often used as initial therapy in patients proceeding to stem cell transplant (SCT), and based on the initial response, are usually considered for salvage therapy during their disease course. However, the retreatment efficacy of these compounds is unknown. We conducted this study to ascertain the degree of response that can be obtained by retreatment with immunomodulatory compounds. Patients and Method: 410 patients with newly diagnosed MM who received either thalidomide-dexamethasone or lenalidomide-dexamethasone were studied. Of these, 183 patients received thalidomide, lenalidomide or pomalidomide (with or without dexamethasone) as one of the salvage regimens following relapse, and form the study group. We included all patients who received the repeat immunomodulatory therapy as salvage treatment at any time during the MM disease course. Results: The median (range) age of the MM patient group was 60 (29-80) years; 117 (64%) were male. Thalidomide and lenalidomide were used as initial therapy in 106 (58%) and 77 (42%) patients, respectively. Patients received a median of 2 treatments (range, 1–6) prior to salvage therapy; bortezomib was used as one of the salvage treatment (prior to the repeat immunomodulatory therapy) in 41 (22%) patients. An autologous stem cell transplant was performed in 118 (64%) patients after the initial immunomodulatory therapy. Almost one half (89; 49%) of the patients went off the first line therapy to undergo a SCT; whereas drug toxicity (26; 14%) and disease progression (21; 11%) were other causes requiring a treatment change. The compound used for salvage therapy was thalidomide, lenalidomide or pomalidomide in 40 (22%), 129 (70%) and 14 (8%) patients, respectively. The responses to salvage therapy based on the initial therapy and the salvage regimen are as shown in Table 1. Overall, 67 (37%) patients achieved a partial response or better and 73 (40%) patients achieved less than a partial response (stable and progressive disease) to repeat immunomodulatory therapy, while the remaining 43 (23%) had non evaluable disease response. Conclusions: Retreatment with an immunomodulatory therapy, especially a different compound, was associated with excellent response rates. Lowest response rates were seen in patients retreated with thalidomide after having received lenalidomide as their initial therapy after the diagnosis of MM. This information is valuable in deciding on the choice of repeat therapy with immunomodulatory compounds in patients with relapsed disease. Disclosures: Dispenzieri: Celgene: Honoraria, Research Funding; Binding Site: Honoraria. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding.

Abstract Abstract 3211 Poster Board III-148 Although autologous stem cell transplantation (ASCT) has become standard of care for many patients with hematologic malignancies, many patients fail to collect a minimum number of CD34 + stem cells to support high dose chemotherapy and ASCT. Recently, plerixafor, a CXCR4 antagonist, was FDA approved for use in combination with G-CSF for autologous peripheral blood stem cell mobilization in patients with NHL or Multiple Myeloma. In February 2009, we commenced a risk adapted approach to the utilization of plerixafor. The study was restricted to patients mobilized with GCSF alone and patients undergoing chemotherapy primed PBSC mobilization were excluded. Peripheral blood stem cell mobilization was commenced with G-CSF at 10 mcg/kg/day. On day 4, a peripheral blood (PB) CD34 count was measured. For patients whose PB CD34 was ≥10/μL, apheresis was commenced the following morning. For patients whose PB CD34 was <10/μL, it was measured again on day 5; if ≥10/μL then apheresis was commenced the following morning. If PB CD34 was <10/μL on day 5, plerixafor (0.24 mg/kg sc) was administered on the evening of day 5 and apheresis was commenced the following day (Group A). In addition, during apheresis, for patients whose collection yield was < 0.5 × 106 CD34/kg, in the absence of instrument failure or problems with the collection procedure, plerixafor was added (Group B). Morning administration of G-CSF and evening dosing of plerixafor continued daily until apheresis was complete. From February to July 2009, 174 mobilization attempts occurred; 27 with chemotherapy and 147 with cytokines alone. The 147 pts who underwent mobilization with cytokines alone are presented here. The underlying diagnosis was as follows: Myeloma 61 pts, NHL 54 pts, Amyloid 17 pts, Hodgkin 10 pts, POEMS 4 pts and 1 pt with a solid tumor. For the entire group the median number of CD34 cells collected was 5.5 × 106 CD34/kg (range 0.1-17). The median number of apheresis was 3 (range 1-12). 67 patients (46%) received plerixafor; 37 patients started plerixafor during mobilization (Group A) and 30 patients during collections due to a poor yield (Group B). 12 pts of the 37 received plerixafor on day 4 because of prior mobilization failure or high risk of mobilization failure and are included in Group A. Table 1 outlines the details of mobilization and collection by groups. By disease category, of the 61 patients with MM, 28 (46%) received plerixafor (8 Group A and 20 Group B). Median apheresis in all the MM pts was 2 (range 1-12) with a total of 6.8 × 106 CD34/kg (2.2-16.7). In the 54 NHL pts, 32 (59%) received plerixafor (24 Group A and 8 Group B). Median apheresis for all pts with NHL was 3 (range 1-7) with a total of 4.6 × 106 CD34/kg (range 0-11.4). Overall, only 7 of 147 (5%) mobilization attempts failed to achieve a minimum of 2 × 106 CD34/kg. This compares to a 22% failure rate prior to institution of this risk adapted approach. In conclusion, implementing this risk adapted approach allows poor mobilizers to be identified promptly and for plerixafor to be initiated during mobilization and collection, thereby reducing the number of mobilization failures. In patients who predictably would not have successful collection based on a PB CD34 <10/μL, addition of plerixafor results in a majority of patients achieving an adequate collection. This risk adapted approach may be more cost effective than reattempting mobilization after a prior failure or utilizing combination G-CSF and plerixafor for upfront mobilization. Table 1. Mobilization and Collection data. All patients N=147 Group A1 N=37 Group B2 N=30 No Plerixafor N=80 PB CD34 day 4 Median 11 0 7 19 Range 0-331 0-7 0-32 0-331 PB CD34 day 5 Median 10 4.5 12 15 Range 0-51 2-9 11-23 9-51 Apheresis Yield Median 5.5 4.4 6.0 6.2 Range 0.1-17 3.1-12.7 3.0-12.2 2-17 Number of Apheresis Median 3 3 5 2 Range 1-12 1-7 4-12 1-8 Days of Plerixafor Median n/a 3 2 n/a Rang 1-7 1-8 1 Group A – Plerixafor initiated prior to apheresis 2 Group B – Plerixafor initiated during apheresis Disclosures No relevant conflicts of interest to declare.

Abstract Background: The advent of high-dose therapy and autologous stem cell transplantation (HDT-ASCT) has significantly improved response rates and survival for patients with multiple myeloma (MM). However this form of therapy is potentially toxic and does not cure patients from their disease. The response to HDT-ASCT is variable and approximately 40% of patients achieve a complete response (CR). Patients with a CR have a significantly improved time to progression (TTP) compared to patients who do not achieve CR (nCR). Optimal timing of HDT-ASCT and considerations of the relapse kinetics may assist treatment planning for this disease. We analyzed myeloma tumor burden and kinetics before and after HDT-ASCT in order to define optimal timing of this therapy for the individual patient. Patients and Methods: A cohort of 265 patients with MM who underwent HDT-ASCT at Mayo Clinic Rochester was studied. Disease burden before and after HDT-ASCT was estimated from serial M-spike measurements. The estimated tumor burden data were fitted to the Gompertz function and its parameters alpha and beta estimated using a non-linear least squares method. Cohorts of patients with CR and nCR were studied separately. Functions that coupled disease burden and kinetics with TTP were derived and used to determine the optimal timing of single and tandem transplantation. Results: The Gompertz parameters alpha and beta for patients who achieved CR and for those who did not achieve CR with HDT were determined. Our values were lower than those of Sullivan and Salmon although the ratio of alpha/beta was of a similar order (implying the same carrying capacity). Using the idealized Gompertz parameters, simulations of single versus tandem transplants were performed. Our model predicts that tandem transplantation increases CR rate by approximately 10%. When the time between transplants was studied as a variable, our model suggests that the optimal time between transplants is 7 months. Conclusions: Our modeling provides a theoretical understanding of tumor burden and kinetics for patients with MM who undergo HDT-ASCT. Patients who achieve CR with the first episode of HDT-ASCT should not be routinely offered tandem transplantation but carefully monitored and re-transplanted at an optimal disease burden. If CR is not achieved with a first cycle of HDT-ASCT, the probability of CR after a second trial of HDT is ~10% (similar to that reported by Attal et al 2003) although this depends on the tumor burden before the second transplant. TTP after tandem transplants (with its higher associated mortality) cannot be superior to TTP achieved with optimally timed serial transplants. Individualized HDT-ASCT for patients with MM is possible and may improve results.

Abstract Abstract 2142 Poster Board II-119 High-dose chemotherapy in conjunction with autologous SCT is the preferred treatment of relapsed Hodgkin disease and non-Hodgkin lymphoma and newly diagnosed multiple myeloma. Failure to achieve optimal stem cell mobilization results in multiple subsequent attempts, which consumes large amounts of growth factors and potentially requires antibiotics and transfusions. We retrospectively reviewed the natural history of stem cell mobilization attempts at our institution from 2001 through 2007 to determine the frequency of suboptimal mobilization in patients with hematologic malignancy undergoing autologous transplant and analyzed the subsequent resource utilization in patients with initially failed attempts. Of 1,775 patients undergoing mobilization during the study period, stem cell collection (defined by the number of CD34+ cells/kg) was “ optimal” (≥5×106) in 53%, “low” (≥2 to 5×106) in 25%,“ poor” (<2×106) in 10%, and “failed” (<10 CD34+ cells/mL) in 12%. In the 47% of collections that were less than optimal, increased resource consumption included increased use of growth factors and antibiotics, subsequent chemotherapy mobilization, increased transfusional support, more apheresis procedures, and more frequent hospitalization. Other costs often omitted include the need for hospitalization, which was seen in 5% to 11% of the patients in our study. Parenteral antibiotics were needed when fever developed in 7% of patients with Hodgkin disease, 4% with non-Hodgkin lymphoma, and 24% with multiple myeloma who underwent mobilization using a chemotherapy pulse. When stem cell mobilization was not immediately optimal, subsequent attempts to mobilize failed completely in 3 of 42 patients (7%) with Hodgkin disease (3% of the original Hodgkin disease cohort), 56 of 157 (36%) with multiple myeloma (6% of the original myeloma cohort), and 50 of 328 (15%) with non-Hodgkin lymphoma (7% of the original non-Hodgkin lymphoma cohort). These usually unappreciated costs of stem cell mobilization failure highlight the need for more effective mobilization strategies. Disclosures: Gertz: genzyme: Research Funding.

Abstract Abstract 2803 Poster Board II-779 Background. The rate of asymptomatic amyloidosis (asym-amyloidosis) detected in patients with newly diagnosed multiple myeloma (MM) or smoldering multiple myeloma (SMM) is unknown. This topic is significant because unrecognized AL may be associated with increased mortality may change the patient's management. The objective of the present investigation was to evaluate the number and clinical significance of asym-amyloidosis in MM and SM patients at the time of the diagnostic bone marrow (BM) biopsy for MM. Materials and Methods. The study population was selected from the Mayo Clinic Dysproteinemia database and consisted of consecutive patients with an established diagnosis of MM or SMM without recognition of symptomatic AL. Bone marrow biopsies at diagnosis of MM or SMM were retrospectively stained with Congo Red and reviewed by a single pathologist. A patient was considered to have asym-amyloid if Congo Red staining with apple green birefringence was found. Results. Biopsies from 144 (M 84, F 59) patients were evaluated: 77 had a diagnosis of MM and 67 of SMM. The median age was 59 (range 26-84) years. No differences were found regarding hemoglobin, platelets, prothrombin time, serum and urine proteins, serum albumin, alkaline phosphate, creatinine and β2-microglobulin among MM and SMM patients. At a median follow-up 76 months (range 0-216), 32% patients were alive, 65% dead and 2.7% lost to follow-up. Immunoglobulin isotypes were as follows: 96/144 (67%) had IgG 23/144 (16%) IgA, 12/144 (8%) had light chain only, 1/77 (1%) had IgD, none had IgM and 12/144 (8%) had biclonal or indeterminate; 84/144 (58%) were κ restricted. The presence of amyloid was found in only 2 cases (1%, 95% CI – 0.6 to 3.2), 1 in MM and 1 in SMM group. Neither of these patients had or developed signs or symptoms suggestive of organ involvement by amyloid. Among the 142 other patients without amyloid deposition in their index bone marrow, 1 (0.7%, 95% CI -0.6 to 2.0) developed symptomatic AL after 119 months of follow-up. Characteristics of these three patients are shown in table 1. Conclusions. We found only 2 cases (1%) of amyloidosis in the 144 cases of MM or SMM. Our estimates are lower than the rates which have been reported by others, perhaps because of our high level of suspicion for amyloid at our Amyloidosis Center. These data do not support the need for searching for asym-amyloidosis in patients with newly diagnosed MM or SMM as long as they have no clinical features of AL. Disclosures: Off Label Use: Hydroxyurea use in myelofibrosis. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Witzig:Novartis: Research Funding. Kumar:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract Background: High dose therapy with autologous stem cell transplantation (HDT-ASCT) has prolonged survival in patients with multiple myeloma. Patients who achieve a complete response (CR) benefit the most from this form of therapy. Thus, achieving a CR is an important goal of therapy and it will be beneficial if the probability of achieving CR can be determined for any patient before transplant. Patients and Methods: A large cohort of patients with myeloma who received HDT-ASCT at Mayo Clinic Rochester was studied. The impact of various demographic, clinical and laboratory characteristics relating to the patients and their disease acquired were studied for their impact on response to HDT-ASCT, especially CR. Patients with a serum M-protein <0.1g/dL were excluded. Response definitions were as defined by established criteria. Survival analysis was performed according to the Kaplan-Meier method while univariate and multivariate analyses were performed with the proportional hazards method. We utilized knowledge of the rate of M-protein production by myeloma cells together with the clearance of the protein to estimate the pre-transplant disease burden. Results: We studied 224 patients with a median age of 56.5 years (32.6 – 71). Patients were transplanted a median of 8.7 months after diagnosis. Almost all patients had a response to HDT-ASCT and 78 (35%) achieved a CR. Those patients who achieved a CR had a longer time to progression (TTP) compared to those who did not achieve CR (Figure 1). The cohort was thus divided into two groups: patients who achieved CR and those that did not. The clinical and laboratory characteristics of the two groups were compared. Among the pre-transplant parameters tested, only the size of the serum M-spike was a predictor for CR (p<0.0001). A simple function that describes the probability of achieving CR based on the serum M-spike before HDT-ASCT is described. The estimated rate of tumor re-growth after HDT-ASCT in patients who obtain a CR and in patients who only get a partial response are presented. Conclusions: The pre-transplant disease burden in myeloma is the main determinant of response to HDT-ASCT. The individual probability of achieving CR can be estimated from simple clinical parameters providing a quantitative risk assessment prior to such a high-risk procedure. There is significant expansion of myeloma cells after HDT-ASCT. The design of clinical trials may benefit from knowledge of the kinetic aspects of the disease. Figure Figure

Abstract Background: High dose melphalan followed by autologous stem cell transplant (ASCT) is an effective treatment of immunoglobulin light chain amyloidosis (AL). However, the high treatment related mortality (TRM, death before day 100) remains a serious concern and is the major drawback of this therapy. A better understanding the risk factors contributing to TRM could help physicians choose the most appropriate therapy for these patients. We performed a retrospective study to identify risk factors that contribute to TRM after ASCT in AL patients. Methods: All patients who underwent ASCT for AL at our institution from 7/96 to 12/04 were studied. Data were collected on age, sex, septal thickness, glomerular filtration rate (GFR), B2M, CRP, proteinuria, albumin, cardiac troponin T (cTnT) and alkaline phosphate. Results: A total of 218 patients underwent ASCT for AL during this time period. One patient refused consent for this study. Pretransplant cTnT was available on 161 (73.9%) patients. The overall TRM rate for the 217 patients was 12.4%. By univariate analysis, septal thickness, GFR, albumin, alkaline phosphatase and cTnT were found to be associated with TRM. In the multivariate analysis, only albumin, alkaline phosphatase and cTnT remained independent predictors of TRM. Cutoffs were identified using receiver-operator characteristic (ROC) curve. The cutoff for albumin was 2.85 g/dL, 249 U/L for alkaline phosphatase and 0.02 ng/mL for cTnT. The percentage of patients with low albumin, elevated cTnT and alkaline phosphatase were 51.1%, 20.5% and 12.4% respectively. The TRM rate of patients with low albumin was 18.0%, 27.3% for elevated cTnT and 29.6% for high alkaline phosphatase. Risk of TRM increased significantly with each additional risk factor (Table). Discussion: In our AL population, low serum albumin, elevated alkaline phosphatase and cTnT were independent risk factors of TRM after ASCT. Patients with 2 or more risk factors are at significant risk of TRM during ASCT. In these high risk patients, alternative therapy should be considered in order to avoid excessively high incidence of TRM. Treatment Related Mortality by Number of Risk Factors Risk Factors 0 1 2 3 Rate of TRM 1.8% 8.4% 35.0% 66.0% Odds Ratio 5.0 29.1 108.0