The effect of mobilizing large numbers of CD34 + cells (super-mobilizers) on the engraftment and survival in patients undergoing autologous stem cell transplantation

With the use of plerixafor in addition to growth factor for peripheral blood stem cell mobilization, the yield of autologous stem cell harvest has been higher while the length of apheresis days has become shorter. There is still debate whether higher cell collection efficacy in autologous stem cell transplant (ASCT) affect outcomes. In this retrospective study, we defined two groups of patients, group 1, super-mobilizers, with more than double the target cell dose collected (n = 15), while group 2 included all other patients (n = 75). Multiple myeloma (MM) and lymphoma patients were combined. Patients with chemo-mobilization, those needed more than one day apheresis, or with less than 100 days after ASCT were excluded. Correlations were performed between cell collection efficacy and post thaw CD34 cell viability (by 7AAD flow cytometry method), product HCT, and engraftment of neutrophils and platelets. We performed multiple linear regression using the above variables in addition to age, sex and disease type. We used Kaplan Meier's curves to show effect of cell collection efficacy on 1-year overall survival (OS). Our results show that all super-mobilizers received plerixafor in addition to G-CSF, while 83% did in group 2. Correlations between cell collection efficacy and neutrophil and platelet engraftment in group 1 and 2 was modest and better in group 1 (R=0.449 Vs 0.233 for neutrophils; R=0.464 Vs 0.110 for platelets, respectively). However, multiple linear regression showed statistically significant association between cell collection, as a continuous variable, with disease type (P < 0.001), product HCT (P < 0.001), post thaw viability (P = 0.003), and age (P = 0.013). MM patients were more likely to be super-mobilizers, while the product HCT was higher in the super-mobilizers. No significant effect of cell collection efficacy was found on engraftment of neutrophils or platelets. With relatively short post ASCT follow up, 6 patients in group 2 died of any cause while no deaths were recorded in the super-mobilizers group (P = 0.1892 by log-rank test). In conclusion, stem cell collection efficacy in ASCT is more frequent in MM than lymphoma patients, but is not predictive of faster engraftment. On the other hand, 1-year OS was 100% in the super-mobilizers group versus 93% in the other group.

Genome-wide Association Study Identified Chromosome 8 Locus Associated with Medication-Related Osteonecrosis of the Jaw

Medication‐related osteonecrosis of the jaw (MRONJ) is a rare but serious drug‐related adverse event. To identify pharmacogenomic markers of MRONJ associated with bisphosphonate therapy, we conducted a genomewide association study (GWAS) meta‐analysis followed by functional analysis of 5,008 individuals of European ancestry treated with bisphosphonates, which includes the largest number of MRONJ cases to date (444 cases and 4,564 controls). Discovery GWAS was performed in randomly selected 70% of the patients with cancer and replication GWAS was performed in the remaining 30% of the patients with cancer treated with intravenous bisphosphonates followed by meta‐analysis of all 3,639 patients with cancer. GWAS was also performed in 1,369 patients with osteoporosis treated with oral bisphosphonates. The lead single‐nucleotide polymorphism (SNP), rs2736308 on chromosome 8, was associated with an increased risk of MRONJ with an odds ratio (OR) of 2.71 and 95% confidence interval (CI) of 1.90–3.86 (P = 3.57*10⁻⁸) in the meta‐analysis of patients with cancer. This SNP was validated in the MRONJ GWAS in patients with osteoporosis (OR: 2.82, 95% CI: 1.55–4.09, P = 6.84*10⁻⁴). The meta‐analysis combining patients with cancer and patients with osteoporosis yielded the same lead SNP rs2736308 on chromosome 8 as the top SNP (OR: 2.74, 95% CI: 2.09–3.39, P = 9.65*10⁻¹¹). This locus is associated with regulation of the BLK, CTSB, and FDFT1 genes, which had been associated with bone mineral density. FDFT1 encodes a membrane‐associated enzyme, which is implicated in the bisphosphonate pathway. This study provides insights into the potential mechanism of MRONJ.

Lactate Dehydrogenase B and Pyruvate Oxidation Pathway Associated With Carfilzomib-Related Cardiotoxicity in Multiple Myeloma Patients: Result of a Multi-Omics Integrative Analysis

Multiple myeloma (MM) is the second most frequent hematologic cancer in the United States. Carfilzomib (CFZ), an irreversible proteasome inhibitor being used to treat relapsed and refractory MM, has been associated with cardiotoxicity, including heart failure. We hypothesized that a multi-omics approach integrating data from different omics would provide insights into the mechanisms of CFZ-related cardiovascular adverse events (CVAEs). Plasma samples were collected from 13 MM patients treated with CFZ (including 7 with CVAEs and 6 with no CVAEs) at the University of Florida Health Cancer Center. These samples were evaluated in global metabolomic profiling, global proteomic profiling, and microRNA (miRNA) profiling. Integrative pathway analysis was performed to identify genes and pathways differentially expressed between patients with and without CVAEs. The proteomics analysis identified the up-regulation of lactate dehydrogenase B (LDHB) [fold change (FC) = 8.2, p = 0.01] in patients who experienced CVAEs. The metabolomics analysis identified lower plasma abundance of pyruvate (FC = 0.16, p = 0.0004) and higher abundance of lactate (FC = 2.4, p = 0.0001) in patients with CVAEs. Differential expression analysis of miRNAs profiling identified mir-146b to be up-regulatein (FC = 14, p = 0.046) in patients with CVAE. Pathway analysis suggested that the pyruvate fermentation to lactate pathway is associated with CFZ-CVAEs. In this pilot multi-omics integrative analysis, we observed the down-regulation of pyruvate and up-regulation of LDHB among patients who experienced CVAEs, suggesting the importance of the pyruvate oxidation pathway associated with mitochondrial dysfunction. Validation and further investigation in a larger independent cohort are warranted to better understand the mechanisms of CFZ-CVAEs.

Melflufen and Dexamethasone in Heavily Pretreated Relapsed and Refractory Multiple Myeloma

PURPOSE

Melphalan flufenamide (melflufen) is a first-in-class peptide-drug conjugate that targets aminopeptidases and rapidly and selectively releases alkylating agents into tumor cells. The phase II HORIZON trial evaluated the efficacy of melflufen plus dexamethasone in relapsed and refractory multiple myeloma (RRMM), a population with an important unmet medical need.

PATIENTS AND METHODS

Patients with RRMM refractory to pomalidomide and/or an anti-CD38 monoclonal antibody received melflufen 40 mg intravenously on day 1 of each 28-day cycle plus once weekly oral dexamethasone at a dose of 40 mg (20 mg in patients older than 75 years). The primary end point was overall response rate (partial response or better) assessed by the investigator and confirmed by independent review. Secondary end points included duration of response, progression-free survival, overall survival, and safety. The primary analysis is complete with long-term follow-up ongoing.

RESULTS

Of 157 patients (median age 65 years; median five prior lines of therapy) enrolled and treated, 119 patients (76%) had triple-class-refractory disease, 55 (35%) had extramedullary disease, and 92 (59%) were refractory to previous alkylator therapy. The overall response rate was 29% in the all-treated population, with 26% in the triple-class-refractory population. In the all-treated population, median duration of response was 5.5 months, median progression-free survival was 4.2 months, and median overall survival was 11.6 months at a median follow-up of 14 months. Grade ≥ 3 treatment-emergent adverse events occurred in 96% of patients, most commonly neutropenia (79%), thrombocytopenia (76%), and anemia (43%). Pneumonia (10%) was the most common grade 3/4 nonhematologic event. Thrombocytopenia and bleeding (both grade 3/4 but fully reversible) occurred concomitantly in four patients. GI events, reported in 97 patients (62%), were predominantly grade 1/2 (93%); none were grade 4.

CONCLUSION

Melflufen plus dexamethasone showed clinically meaningful efficacy and a manageable safety profile in patients with heavily pretreated RRMM, including those with triple-class-refractory and extramedullary disease.

Functional Improvement of Chimeric Antigen Receptor Through Intrinsic Interleukin-15Rα Signaling

INTRODUCTION

Recent studies on CD19-specific chimeric antigen receptor (CAR)-modified T cells (CARTs) have demonstrated unprecedented successes in treating refractory and relapsed B cell malignancies. The key to the latest CART therapy advances can be attributed to the improved costimulatory signals in the CAR design.

METHODS

Here, we established several novel CARs by incorporating T cell signaling domains of CD28 in conjunction with intracellular signaling motif of 4-1BB, CD27, OX40, ICOS, and IL-15Rα. These novel CARs were functionally assessed based on a simple target cell killing assay.

RESULTS

The results showed that the CD28/IL-15Rα co-signaling (153z) CAR demonstrated the fastest T cell expansion potential and cytotoxic activities. IL-15 is a key cytokine that mediates immune effector activities. The 153z CARTs maintained prolonged killing activities after repetitive rounds of target cell engagement. Consistent with the enhanced target killing function, the 153z CARTs produced increased amount of effector cytokines including IFN-γ, TNFα and IL-2 upon interaction with the target cells.

CONCLUSION

In a follow-up clinical study, an acute lymphoblastic leukemia (ALL) patient, who experienced multiple relapses of central nervous system leukemia (CNSL) and failed all conventional therapies, was enrolled to receive the CD19-specific 153z CART treatment. The patient achieved complete remission after the 153z CART cell infusion. The translational outcome supports further investigation into the safety and enhanced therapeutic efficacy of the IL-15Rα-modified CART cells in cancer patients.

Pharmacogenomics of osteonecrosis of the jaw

Osteonecrosis of the jaw (ONJ) is a rare but serious drug induced adverse event, mainly associated with the use of antiresorptive medications, such as intravenous (IV) bisphosphonates (BPs) in cancer patients. In this review, we evaluated all the pharmacogenomic association studies for ONJ published up to December 2018. To date, two SNPs (CYP2C8 rs1934951 and RBMS3 rs17024608) were identified to be associated with ONJ by two genome-wide association studies (GWAS). However, all six subsequent candidate gene studies failed to replicate these results. In addition, six discovery candidate gene studies tried to identify the genetic markers in several genes associated with bone remodeling, bone mineral density, or osteoporosis. After evaluating the results of these 6 studies, none of the SNPs was significantly associated with ONJ. Recently, two whole-exome sequencing (WES) analysis (including one from our group) were performed to identify variants associated with ONJ. So far, only our study successfully replicated discovery result indicating SIRT1 SNP rs7896005 to be associated with ONJ. However, this SNP also did not reach genome-wide significance. The major limitations of these studies include lack of replication phases and limited sample sizes. Even though some studies had larger sample sizes, they recruited healthy individuals as controls, not subjects treated with BPs. We conclude that a GWAS with a larger sample size followed by replication phase will be needed to fully investigate the pharmacogenomic markers of ONJ.

Cardiotoxicity due to targeted anticancer agents: a growing challenge

The emergence of various targeted anticancer agents has led us to uncharted territory secondary to their cardiotoxic potential with many burning questions, which in turn has led to the evolution of the cardio-oncology field. These targeted agents differ in their cardiovascular complication (CVC) potential even within the same class and it is very difficult to design screening tests that can predict CVCs. Moreover, there is a need for more research to answer many crucial questions, since these toxicities are unanticipated and can lead to poor overall survival of cancer patients. We still do not clearly understand the mechanism for such toxicity, risk factors, and natural history. A better understanding of the underlying risk factors and identification of biomarkers would help us develop protocols for appropriate monitoring strategies which in turn would help capture these toxicities at early stages. In this succinct review, we try to focus on CVC definition, summarize some published research, and point to areas of unmet need in this new field.

Efficacy and safety of carfilzomib in relapsed and/or refractory multiple myeloma: systematic review and meta-analysis of 14 trials

OBJECTIVE

Carfilzomib (Carf) is a second-generation proteasome inhibitor approved for patients with relapsed and/or refractory multiple myeloma (RRMM) who failed ≥ 1 prior lines of therapy. We performed a systematic review of Carf literature with meta-analysis to determine the efficacy and safety in RRMM patients.

METHODS

Based on literature search, we included a total of 14 eligible phase I/II, phase II and phase III Carf based clinical trials. The cumulative incidence and odds ratios (OR) were calculated with random effect model, using ''R'' software with metaphor package.

RESULTS

2906 evaluable RRMM patients from published clinical trials included. The pooled overall response rate (ORR) was 45% (95% CI: 29-62). The pooled clinical benefit rate (CBR) was 56% (95% CI: 41-71). OR from 3 randomized clinical trials showed that Carf significantly improved ORR and CBR compared to control groups (OR 2.4, P < 0.0001; 2.02, P = 0.0007, respectively). Subgroup analysis showed significantly better ORR (P < 0.0001) and CBR (P < 0.001) with combination regimens compared to monotherapy. Response was significantly higher with high dose of Carf (>20/27 mg/m2) compared to standard dose (ORR 65% vs. 35%, P = 0.03). Compared to control group, the OR of developing cardiotoxicity (P = 0.002) and hypertension (P < 0.0001) were significantly higher with Carf, while no difference in peripheral neuropathy (P = 0.28).

CONCLUSIONS

Carf produces significantly better responses with acceptable safety profile in RRMM patients. Combination regimens and higher dose Carf offers better response with no significant extra toxicity. Its efficacy is regardless of cytogenetics or disease stage. Incidences of cardiotoxicity and hypertension seem higher with Carf.

Cardiotoxicity associated with carfilzomib: systematic review and meta-analysis

Carfilzomib is a second-generation proteasome inhibitor (PI) that is approved for patients with relapsed or refractory multiple myeloma (RRMM) who failed ≥1 prior lines of therapy. We performed a systematic review of carfilzomib literature with meta-analysis to determine cumulative incidence of cardiotoxicity. After the literature search, we included a total of 29 eligible phase I/II, phase II and phase III clinical trials which used carfilzomib. The cumulative incidence and overall odds ratios (OR) were calculated with random effect model, using 'R' software with metaphor package. A total of 4164 patients with various malignancies were included. The overall estimated cumulative incidence of cardiotoxicity was 8.68% and 4.92%, respectively, for all-grade and high-grade (≥ grade 3) toxicity, which seems higher than other PIs. Compared to control group, the odds of developing cardiotoxicity due to carfilzomib was significantly higher with OR of 2.03 (95% CI: 1.19-3.46, p = .010) and 2.04 (95% CI: 1.31-3.17, p = .002) for all-grades and high grades, respectively. Concomitant immunomodulatory agents seem to increase the risk of cardiotoxicity (high-grade cardiotoxicity 6.45% and 4.34% with and without concomitant immunomodulatory agents, respectively (p = .033)). There was no variation in the incidence of cardiotoxicity among newly diagnosed versus RRMM (p = .38), and high versus standard dose carfilzomib (p = .86).

SIRT1/HERC4 Locus Associated With Bisphosphonate-Induced Osteonecrosis of the Jaw: An Exome-Wide Association Analysis

Osteonecrosis of the jaw (ONJ) is a rare, but serious drug side effect, mainly associated with the use of intravenous (iv) bisphosphonates (BPs). The purpose of this study was to identify genetic variants associated with ONJ in patients of European ancestry treated with iv BPs using whole-exome sequencing (WES). The WES phase 1 included 44 multiple myeloma patients (22 ONJ cases and 22 controls) and WES phase 2 included 17 ONJ patients with solid tumors. Multivariable logistic regression analysis was performed to estimate the odds ratios (ORs) and 95% confidence intervals (CI), adjusting for age, sex, and principal components for ancestry. Meta-analysis of WES phase 1 and 2 was performed to estimate the combined ORs. In silico analyses were then performed to identify expression quantitative loci (eQTL) single-nucleotide polymorphisms (SNPs) that are in high linkage disequilibrium (LD) with the top SNPs. The associations of the potentially functional SNPs were replicated and validated in an independent case-control study of 48 patients of European ancestry treated with iv BPs (19 ONJ cases and 29 controls). The top SNPs in the exome-wide association meta-analysis were two SNPs on chromosome 10: SIRT1 SNP rs7896005 and HERC4 SNP rs3758392 with identical OR of 0.07 (0.01-0.46; p = 3.83 × 10^-5 ). In the in silico functional analyses, two promoter region SNPs (rs7894483 and rs3758391) were identified to be in high LD with the index SNPs and are eQTLs for SIRT1 gene in whole blood in the GTEx database. The ORs were 0.30 (0.10-0.88), 0.26 (0.12-0.55), and 0.26 (0.12-0.55) for the WES top SNP rs7896005 and two promoter SNPs rs7894483 and rs3758391, respectively, in the replication sample. In summary, we identified the SIRT1/HERC4 locus on chromosome 10 to be associated with iv BP-induced ONJ and two promoter SNPs that might be the potential genetic markers for this association. © 2017 The Authors.Journal of Bone and Mineral Research Published by Wiley Periodicals Inc.

Updated analysis of CALGB (Alliance) 100104 assessing lenalidomide versus placebo maintenance after single autologous stem-cell transplantation for multiple myeloma: a randomised, double-blind, phase 3 trial

Background

CALGB 100104 (Alliance) studied lenalidomide vs. placebo following autologous stem cell transplant (ASCT) for newly diagnosed myeloma patients, demonstrating improved time to progression (TTP) and overall survival (OS), and an increase in second primary malignancies (SPM) for lenalidomide at 34-months median follow-up. Here we report an updated intent-to-treat analysis at 91-months median follow-up.

Methods

Patients were eligible if they had active myeloma, had received at most two induction regimens and had achieved stable disease or better in the first 100 days after ASCT. In this phase 3 study, 460 patients were randomised in a double-blind manner to either lenalidomide (n=231) or placebo (n=229) utilizing a permutated-block randomisation with fixed block size. Randomisation was stratified by three factors: normal or elevated β2-microglobulin level at registration (≤2·5 mg/L vs > 2·5 mg/L), prior use or nonuse of thalidomide during induction therapy, and prior use or nonuse of lenalidomide during induction therapy. The starting dose was 10 mg daily, escalated to 15 mg daily after three months. The primary endpoint was TTP (time of progressive disease or death from any cause) using intent-to-treat analysis. After three interim analyses, the study was unblinded at median follow-up of 18 months and 86/128 placebo patients without progressive disease chose to cross over to lenalidomide. This study is registered with ClinicalTrials.gov identifier NCT00114101; new patients are no longer being recruited, but some patients remain on treatment and in follow-up.

Findings

The median TTP for lenalidomide is 57·3 months (95% CI 44·2–73·3) and 28·9 months (95% CI 23·0–36·3) for placebo (hazard ratio (HR): 0·57, 95% CI 0·46–0·71, p<0·0001). The TTP benefit with lenalidomide was observed regardless of whether patients were in a complete response at time of randomisation or whether they had received thalidomide or lenalidomide induction therapy. The most common grade 3–4 adverse events were neutropenia (116 (50%) of 231 patients in the lenalidomide arm and 37 (16%) of 229 patients in the placebo arm) and thrombocytopenia (34 patients (15%) in the lenalidomide arm and 11 patients (4·8%) in the placebo arm. Eighteen haematological (7·8%) and 14 solid tumour (6·1%) SPMs have been diagnosed following randomisation and prior to disease progression in the lenalidomide arm vs. three haematological (1·3%) and nine solid tumour (3·9%) SPMs in the placebo arm. Of the placebo SPMs, three haematological and five of nine solid tumour SPMs were in the crossover subgroup.

Interpretation

Despite an increase in haematological adverse events and SPMs, lenalidomide maintenance therapy following ASCT significantly improves TTP and can be considered a standard of care.

Abstract 987: Unanticipated cardiotoxicity due to targeted anti-cancer therapy in hematologic malignancies patients: Natural history and risk factors

INTRODUCTION: Unanticipated cardiotoxicity is now identified as a significant clinical problem associated with new anti-cancer targeted agents. Risk factors and natural history are still poorly understood. We aim to determine potential clinical risk factors for cardiotoxicity among patients with hematologic malignancies (HM) who were treated with targeted therapies over a 10-year period.

METHODS: We used 114 diagnosis codes for HM and 17 codes for cardiac diseases in order to identify patients in our electronic medical records (EPIC) and identify patients with HM who met above criteria. Cardiotoxicity was defined mainly by left ventricular ejection fraction (LVEF) of &lt; 50%, arrhythmias, or ischemic cardiovascular event that occurred after initiation of the drug of interest. The targeted agents of interest include tyrosine kinase inhibitors (TKIs), proteasome inhibitors, monoclonal antibodies, hypomethylating agents, and immunomodulatory agents. Multivariable logistic regression was performed to estimate the odds ratios (ORs) and 95% confidence intervals (95% CI) of the potential risk factors. Kaplan-Meier analysis and log-rank test were used to evaluate the effect of cardiotoxicity on the overall survival of the patients.

RESULTS: Of 820 patients with both HM and cardiac diagnosis, 29 patients developed cardiotoxicity after initiation of targeted therapies. We selected 70 matched controls based on type of targeted therapy. In the study group, the median time from exposure to cardiac event was 120 days (range, 1-1176). Significantly higher number of patients had prior exposure to anthracyclines in study versus control group (65.5% vs 42.8%, P=0.04), however, this was not significant in multivariable analysis. Multiple other variables, including traditional risk factors for heart disease, were analyzed and did not differ significantly between the two groups. Only two variables remained significant in the multivariable analysis, including prior history of DVT/PE (OR 4.88, 95% CI: 1.44-16.54, P=0.011), and Karnofsky score of ≥80% (OR 3.99, 95% CI: 1.51-10.6, P= 0.005). With median follow-up of 27 months (range, 1-120), 17 patients in the study group died, but only 2 of cardiac causes. Repeat echocardiograms showed worsening of LVEF in 4 patients while stable/improved in 23 patients, and 21 patients were able to receive further chemotherapy. There was a trend towards worse overall survival in the study group (P= 0.071).

CONCLUSIONS: About 3.5% of patients with HM experience unanticipated cardiotoxicity due to targeted anti-cancer agents with related mortality of 6.8 %. Most patients do well with stable compensated cardiac function and 35% have an objective improvement in LVEF. Risk of cardiotoxicity was significantly higher in patients with known history of DVT/PE. Future studies of possible underlying genetic predisposition will be of great importance.

Citation Format: Chintan Shah, Yan Gong, Anita Szady, Qian Sun, carl J. Pepine, Taimour Langaee, Alexandra R. Lucas, Jan S. Moreb. Unanticipated cardiotoxicity due to targeted anti-cancer therapy in hematologic malignancies patients: Natural history and risk factors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 987. doi:10.1158/1538-7445.AM2017-987

Use of retinoic acid/aldehyde dehydrogenase pathway as potential targeted therapy against cancer stem cells

A large number of studies have investigated possible drug resistance mechanisms of cancer cells and suggested strategies to overcome it. In this review, we outline the role and function of aldehyde dehydrogenase (ALDH) activity in multiple cellular functions and in cancer stem cells (CSCs) and focus on the role of retinoic acid (RA), one of the products of ALDH isozymes. We discuss our observation that ATRA and other RAs can suppress ALDH activity and decrease different ALDH isozyme proteins and result in detrimental effects on cell proliferation, invasion and chemotherapy sensitivity. We review the known uses of different RAs in the treatment of cancers. We review the use of RAs in combination with chemo-/radiotherapy and the major signaling pathways affected in different tumor types. We provide follow-up on studies that may have used our prior observation with the aim of targeting the CSCs. We conclude with summary of the findings and potential impact of published studies on future use of RAs in the targeting of CSCs and drug resistance.

Ex vivo virotherapy with myxoma virus does not impair hematopoietic stem and progenitor cells

BACKGROUND

Relapsing disease is a major challenge after hematopoietic cell transplantation for hematological malignancies. Myxoma virus (MYXV) is an oncolytic virus that can target and eliminate contaminating cancer cells from auto-transplant grafts. The aims of this study were to examine the impact of MYXV on normal hematopoietic stem and progenitor cells and define the optimal treatment conditions for ex vivo virotherapy.

METHODS

Bone marrow (BM) and mobilized peripheral blood stem cells (mPBSCs) from patients with hematologic malignancies were treated with MYXV at various time, temperature and incubation media conditions. Treated BM cells from healthy normal donors were evaluated using flow cytometry for MYXV infection, long-term culture-initiating cell (LTC-IC) assay and colony-forming cell (CFC) assay.

RESULTS

MYXV initiated infection in up to 45% of antigen-presenting monocytes, B cells and natural killer cells; however, these infections were uniformly aborted in >95% of all cells. Fresh graft sources showed higher levels of MYXV infection initiation than cryopreserved specimens, but in all cases less than 10% of CD34(+) cells could be infected after ex vivo MYXV treatment. MYXV did not impair LTC-IC colony numbers compared with mock treatment. CFC colony types and numbers were also not impaired by MYXV treatment. MYXV incubation time, temperature or culture media did not significantly change the percentage of infected cells, LTC-IC colony formation or CFC colony formation.

CONCLUSIONS

Human hematopoietic cells are non-permissive for MYXV. Human hematopoietic stem and progenitor cells were not infected and thus unaffected by MYXV ex vivo treatment.

Abstract 1431: Incidence and natural history of cardiovascular toxicity associated with biologic and targeted therapies used in hematologic malignancies

INTRODUCTION: Unanticipated cardiac toxicity has been reported with anti cancer targeted and biological treatments. In this retrospective study, we aim at identifying the number of cardiac toxicity cases among patients with hematologic malignancies (HM) who were treated with targeted therapies over 10-year period with emphasis on natural history and outcomes.

METHODS: With the help of the Faculty Practice Decision Support (FPDS) team, we used 114 diagnosis codes for HM and 17 codes for cardiac diseases in order to mine our electronic medical records (EPIC) and identify patients with HM and specific cardiac problems, then sorted them according to whether they received known biologic agents such as thymidine kinase inhibitors (TKIs), proteasome inhibitors, monoclonal antibodies, hypomethylating agents, and immunomodulatory drugs.

RESULTS: FPDS team provided us with a file that contained medical records of 820 patients that had both HM and cardiac abnormalities. We pulled out 53 patients who received the drugs of interest. We were able to confirm cardiac toxicity defined mainly by left ventricular ejection fraction (LVEF) of &lt; 50%, arrhythmias, or ischemic cardiovascular event in 44 patients. Ten patients were excluded because of pre-existing cardiac disease. Thus the final analysis was performed on the remaining 34 patients. The median follow-up was 9 mo (range, 1-78). The median age of this group was 66 years (range, 27-81), male/female 19/15, 26 Caucasians, and 15 were still alive. The median time from exposure to development of cardiac events was 120 days (range, &lt;1-300). The diagnosis distribution was as follows: multiple myeloma 16, B-cell non-Hodgkin's lymphoma (NHL) 10, follicular NHL 4, Philadelphia positive acute lymphoblastic leukemia 3, MDS 1. Number of patients (n) who received suspected drugs contributing to the cardiac toxicity: bortezomib (8), carfilzomib (4), imatinib (2), dasatinib (4), Rituximab (13), and lenalidomide (3). Twenty one patients had no prior cardiac disease, while 11 had known coronary artery disease and 2 had known arrhythmias, while only 9 had no chronic co-morbidities. Fourteen patients did not receive anthracyclines including 2 who received rituximab. Nine patients had elevation in troponin and were diagnosed with NSTE myocardial infarction at the time of cardiac toxicity. Among the 19 dead patients, only 6 died of cardiac causes, while the rest died of their cancers. Repeat echocardiograms showed worsening of LVEF in 5 patients and improvement in 15 patients.

CONCLUSIONS: About 4.1% of patients with HM experience unanticipated cardiac toxicity with related mortality of 17.6%. Most patients do well with stable compensated cardiac function with objective improvement in LVEF. Whether Rituximab can cause cardiac toxicity is controversial and we will present specific arguments.

Citation Format: Jan S. Moreb, Haneen Mohammad, Lindsay McCullough, Anita Szady, Leslie Pettiford, Alexandra Lucas. Incidence and natural history of cardiovascular toxicity associated with biologic and targeted therapies used in hematologic malignancies. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 1431.

Osteonecrosis of the Jaw in the United States Food and Drug Administration's Adverse Event Reporting System (FAERS)

Osteonecrosis of the jaw (ONJ) is a serious adverse drug event that was initially reported with intravenous bisphosphonates (BPs) and more recently with other classes of drugs such as receptor activator of NF-κB ligand (RANKL) inhibitor, antiangiogenic agents, and mammalian target of rapamycin (m-TOR) inhibitors. The purpose of this study is to analyze the ONJ cases and the associated drugs in the US Food and Drug Administration's adverse event reporting system (FAERS). The FAERS database was queried for the adverse drug events reported from the first quarter of 2010 to the first quarter of 2014. The reporting odds ratios (ORs) and 95% confidence intervals (CIs) were calculated for each queried drug. A total of 17,119 unique ONJ cases were identified. In the overall analysis, the drugs with the highest reporting ORs were BPs: pamidronate (OR = 498.9), zoledronate (OR = 171.7), and alendronate (OR = 63.6), whereas denosumab had lower ORs than all the BPs except for etidronate. The antiangiogenic and m-TOR inhibitors had the lowest ORs. In cancer patients who were treated for prevention of skeletal-related events (SREs), the reporting ORs for zoledronate and denosumab were 125.2 and 4.9, respectively. In patients with osteoporosis, the ORs were 1.1 (1.0-1.18) for zoledronate and 0.63 (0.56-0.70) for denosumab, respectively. Our analysis of the FAERS database showed that the intravenous BPs were associated with the highest risk for ONJ, RANKL inhibitor was associated with risk comparable to BPs used for osteoporosis such as etidronate, and the antiangiogenic agents and m-TOR inhibitors were associated with the lowest risk for ONJ. The high risk for ONJ with zoledronate and denosumab was mainly observed in those who were treated for prevention of SREs, whereas there was limited evidence for such risk in those who were treated for osteoporosis.

Improved Outcomes After Autologous Hematopoietic Cell Transplantation for Light Chain Amyloidosis: A Center for International Blood and Marrow Transplant Research Study

PURPOSE

Autologous hematopoietic cell transplantation, or autotransplantation, is effective in light-chain amyloidosis (AL), but it is associated with a high risk of early mortality (EM). In a multicenter randomized comparison against oral chemotherapy, autotransplantation was associated with 24% EM. We analyzed trends in outcomes after autologous hematopoietic cell transplantation for AL in North America.

PATIENTS AND METHODS

Between 1995 and 2012, 1,536 patients with AL who underwent autotransplantation at 134 centers were identified in the Center for International Blood and Marrow Transplant Research database. EM and overall survival (OS) were analyzed in three time cohorts: 1995 to 2000 (n = 140), 2001 to 2006 (n = 596), and 2007 to 2012 (n = 800). Hematologic and renal responses and factors associated with EM, relapse and/or progression, progression-free survival and OS were analyzed in more recent subgroups from 2001 to 2006 (n = 197) and from 2007 to 2012 (n = 157).

RESULTS

Mortality at 30 and 100 days progressively declined over successive time periods from 11% and 20%, respectively, in 1995 to 2000 to 5% and 11%, respectively, in 2001 to 2006, and to 3% and 5%, respectively, in 2007 to 2012. Correspondingly, 5-year OS improved from 55% in 1995 to 2000 to 61% in 2001 to 2006 and to 77% in 2007 to 2012. Hematologic response to transplantation improved in the latest cohort. Renal response rate was 32%. Centers performing more than four AL transplantations per year had superior survival outcomes. In the multivariable analysis, cardiac AL was associated with high EM and inferior progression-free survival and OS. Autotransplantation in 2007 to 2012 and use of higher dosages of melphalan were associated with a lowered relapse risk. A Karnofsky score less than 80 and creatinine levels 2 mg/m(2) or greater were associated with worsened OS.

CONCLUSION

Post-transplantation survival in AL has improved, with a dramatic reduction in early post-transplantation mortality and excellent 5-year survival. The risk-benefit ratio for autotransplantation has changed, and randomized comparison with nontransplantation approaches is again warranted.

Aldehyde dehydrogenases in cancer: an opportunity for biomarker and drug development?

Aldehyde dehydrogenases (ALDHs) belong to a superfamily of 19 isozymes that are known to participate in many physiologically important biosynthetic processes including detoxification of specific endogenous and exogenous aldehyde substrates. The high expression levels of an emerging number of ALDHs in various cancer tissues suggest that these enzymes have pivotal roles in cancer cell survival and progression. Mapping out the heterogeneity of tumours and their cancer stem cell (CSC) component will be key to successful design of strategies involving therapeutics that are targeted against specific ALDH isozymes. This review summarises recent progress in ALDH-focused cancer research and discovery of small-molecule-based inhibitors.

Tandem Autologous Stem Cell Transplantation for Multiple Myeloma Patients Based on Response to Their First Transplant-A Prospective Phase II Study

In this prospective phase II clinical trial, multiple myeloma (MM) patients were randomized to receive a second (tandem) autologous stem cell transplantation (ASCT) based on whether they achieved a partial response or worse (≤PR) following initial ASCT (ASCT1). Patients who achieved a very good partial response or better (≥VGPR) had salvage ASCT at relapse. Seventy-five patients received conditioning therapy and ASCT1. A total of 44 patients (59%) achieved ≥VGPR, whereas 31 patients entered ≤PR and were offered tandem ASCT. In all, 20 patients agreed to tandem ASCT. Demographic and clinical characteristics were similar between the two cohorts except for median lactate dehydrogenase (LDH) (P = 0.0141) and percentage of marrow plasma cells before ASCT1 (P = 0.0047), both lower in the ≥VGPR group. Intent to treat analysis showed that patients who achieved ≥VGPR to ASCT1 had a trend toward improved progression-free survival (PFS) (37 vs. 26 months, P = 0.078) and superior overall survival (OS) (not reached vs. 50 months, P = 0.0073). Patients with ≤PR who declined tandem transplantation had shortened PFS (20 vs. 28 months, P = 0.05) but similar OS (53 vs. 57.5 months, P = 0.29) compared to those who received it. Thus, a favorable clinical response to ASCT1 identifies a low-risk group with superior long-term prognosis despite similar PFS.

Multiple myeloma in bisphosphonate-affected jaws--a diagnostic challenge: case report

OBJECTIVE

To discuss the challenges in diagnosis and appropriate management of critical underlying pathoses if a patient presents with signs and symptoms indicative of different conditions that may coexist.

SUMMARY

This case features clinical and radiographic challenges in reaching a diagnosis in a middle- aged man undergoing bisphosphonate therapy for multiple myeloma. The patient had history of bisphosphonaterelated osteonecrosis of the jaw (BRONJ) in the mandible. The patient presented with pain and swelling in the anterior maxilla, associated with paresthesia of upper lip. The radiographic features were suggestive of BRONJ and invasive fungal sinusitis. MRI appearance was suggestive of malignant involvement by plasmacytoma or lymphoma. Although biopsy is usually not advocated in bisphosphonate-affected jaws, it was advised in this case and was positive for multiple myeloma. Vigilance is required to correlate clinical and radiologic findings and further investigations must be considered if malignancy is suspected.

Oral squamous cell carcinoma positive for p16/human papilloma virus in post allogeneic stem cell transplantation: 2 cases and review of the literature

Complications of allogeneic hematopoietic stem cell transplantation (allo-HSCT) includes the risk of secondary malignancies. This may be related to mechanisms including radiation and chemotherapy regimens, chronic graft-versus-host disease, inflammation, and prolonged imunosuppression. Oral squamous cell carcinoma (OSCC) is a complication associated with chronic graft-versus-host disease after allo-HSCT. Although human papillomavirus (HPV) is known to be associated with OSCC, the role of HPV in development of OSCC in post-HSCT patients has not been studied. We identified 2 cases of OSCC in allo-HSCT recipients. Both biopsy specimens tested positive for p16(INK4A), a surrogate marker for HPV. We propose that the association of OSCC and HPV in patients after allo-HSCT may not be incidental. Clinical implications of these cases may imply the need for a HPV screening, early intervention, and consideration of anti-HPV vaccination in this population. The effectiveness of such interventions could be validated in a prospective clinical study.

Salvage second hematopoietic cell transplantation in myeloma

Autologous hematopoietic cell transplantation (AHCT) as initial therapy of patients with multiple myeloma (MM) improves survival. However, data to support this approach for relapsed/progressive disease after initial AHCT (AHCT1) are limited. Using Center for International Blood and Marrow Transplant Research data, we report the outcomes of 187 patients who underwent a second AHCT (AHCT2) for the treatment of relapsed/progressive MM. Planned tandem AHCT was excluded. Median age at AHCT2 was 59 years (range, 28 to 72), and median patient follow-up was 47 months (range, 3 to 97). Nonrelapse mortality after AHCT2 was 2% at 1 year and 4% at 3 years. Median interval from AHCT1 to relapse/progression was 18 months, and median interval between transplantations was 32 months. After AHCT2, the incidence of relapse/progression at 1 and 3 years was 51% and 82%, respectively. At 3 years after AHCT2, progression-free survival was 13%, and overall survival was 46%. In multivariate analyses, those relapsing ≥36 months after AHCT1 had superior progression-free (P = .045) and overall survival (P = .019). Patients who underwent AHCT2 after 2004 had superior survival (P = .026). AHCT2 is safe and feasible for disease progression after AHCT1. In this retrospective study, individuals relapsing ≥36 months from AHCT1 derived greater benefit from AHCT2 compared with those with a shorter disease-free interval. Storage of an adequate graft before AHCT1 will ensure that the option of a second autologous transplantation is retained for patients with relapsed/progressive MM.

Outcomes of salvage autologous versus allogeneic hematopoietic cell transplantation for relapsed multiple myeloma after initial autologous hematopoietic cell transplantation

BACKGROUND

Standard therapy for multiple myeloma (MM) includes initial autologous hematopoietic cell transplantation (autoHCT1) but this is not curative and most patients will relapse. Role of salvage autoHCT2 or allogeneic HCT (alloHCT2) is undefined.

METHODS

MM patients who relapsed after autoHCT1 and had salvage autoHCT2 (N = 27) or alloHCT2 (N = 19) between 1995 - 2011 at our institution were studied retrospectively.

RESULTS

Complete and very good partial remission (CR/VGPR) improved from 7% to 56% after autoHCT2 and from 26% to 37% after alloHCT2. Nonrelapse mortality (NRM) at 3 years was 3.7% for autoHCT2 and 5.3% for alloHCT2 (P = 0.901). Median progression free survival (PFS) and overall survival (OS) for autoHCT2 (19 months, 23 months) and alloHCT2 (6 months, 19 months) were not significantly different. On multivariate analysis, time from autoHCT1 to relapse ≥ 1year (HR 24.81, 95% CI 2.4 - 249.9) and maintenance therapy after autoHCT2 (HR 12.19, 95% CI 2.5 - 249.9) impacted OS after autoHCT2. Time from autoHCT1 to relapse < 1 year vs. ≥ 1 year (HR 18.55, 95% CI 2.28 - 150.57) impacted PFS after autoHCT2. For alloHCT2, no factors impacted NRM, PFS or OS. For those with relapse from autoHCT1 < 1 year vs. ≥ 1 year undergoing autoHCT2, median OS was 15 months (range, 1 - 53) vs. not yet reached at 143 months and median PFS was 5 months (range, 1 - 49) vs. not yet reached at 88 months.

CONCLUSIONS

Salvage autoHCT2 and alloHCT2 are both feasible for post autoHCT1 MM relapse. Relapse ≥ 1 year from autoHCT1 predicts for better PFS and OS after autoHCT2. Maintenance therapy after autoHCT2 is beneficial.

Abstract 3762: The role of aldehyde dehydrogenase isoenzymes in cancer cell proliferation, migration and drug resistance

Aldehyde dehydrogenase (ALDH) proteins are a superfamily of 19 human genes that play crucial role in epithelial cell homeostatsis. Several of these enzymes have been studied in cancer and were shown to protect cells against cytotoxic drugs and oxidative stress in addition to the promotion of cancer cell proliferation and invasion. Our study focuses on 5 less studied isoenzymes (ALDH1B1, ALDH3B1, ALDH4A1, ALDH5A1, and ALDH7A1) using lentiviral mediated overexpression of the enzymes in H1299 lung cancer cell line which is previously known to have negligible amount of ALDH activity. H1299 wild type cells (WT) and cells expressing GFP or RFP were used as controls. Expression of the proteins was confirmed by Western blots and ALDH enzymatic activity assay. We used cell culture, colorimetric MTT assay, wound healing assay, aldefluor assay, colony-forming assay, and in vitro treatment with doxorubicin (Doxo) and 4-hydroperoxycyclophosphaimde (4-HC). All the proteins were highly expressed and resulted in increased ALDH activity detected by using propionaldehyde or benzaldehyde as substrates with NAD+ as a co-factor. The activity of ALDH4A1, 5A1 and 7A1 was not detected by aldefluor flow cytometry assay. Cells expressing ALDH1B1, ALDH4A1 or ALDH7A1 had delayed wound healing at 6 hr, while overall cell proliferation was depressed for ALDH1B1, ALDH3B1 and ALDH5A1 and normal for the other isoenzymes. Cells overexpressing ALDH4A1 or ALDH7A1 showed higher clonal efficiency as well. Only ALDH1B1 and ALDH7A1 showed significant protection against the toxicity of 4-HC (10 μM for 72 hrs) as measured by MTT assay with an increase in average cell survival of 52 and 23%, respectively. Cells overexpressing ALDH5A1 showed significantly increased sensitivity to Doxo (1 and 10 μM for 72 hrs). There was a trend for ALDH7A1 to be protective against Doxo toxicity but did not reach statistical significance. In conclusion, the overexpression of ALDH isoenzymes in this manner may contribute to better understanding of their role in cancer biology and may lead to new cancer treatment approaches that incorporate specific inhibition or stimulation of these enzymes. This is an important goal especially in view of the high ALDH activity in cancer stem cells and their potential contribution to cancer recurrence.

Citation Format: Jan S. Moreb, Mahmoud Mona, Lung-Ji Chang, Yu-Ling Yeh, John Amory, Alex Goldstein. The role of aldehyde dehydrogenase isoenzymes in cancer cell proliferation, migration and drug resistance. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3762. doi:10.1158/1538-7445.AM2013-3762

Regulation of in vitro human T cell development through interleukin-7 deprivation and anti-CD3 stimulation

BACKGROUND

The role of IL-7 and pre-TCR signaling during T cell development has been well characterized in murine but not in human system. We and others have reported that human BM hematopoietic progenitor cells (HPCs) display poor proliferation, inefficient double negative (DN) to double positive (DP) transition and no functional maturation in the in vitro OP9-Delta-like 1 (DL1) culture system.

RESULTS

In this study, we investigated the importance of optimal IL-7 and pre-TCR signaling during adult human T cell development. Using a modified OP9-DL1 culture ectopically expressing IL-7 and Fms-like tyrosine kinase 3 ligand (Flt3L), we demonstrated enhanced T cell precursor expansion. IL-7 removal at various time points during T cell development promoted a slight increase of DP cells; however, these cells did not differentiate further and underwent cell death. As pre-TCR signaling rescues DN cells from programmed cell death, we treated the culture with anti-CD3 antibody. Upon pre-TCR stimulation, the IL-7 deprived T precursors differentiated into CD3+TCRαβ+DP cells and further matured into functional CD4 T cells, albeit displayed a skewed TCR Vβ repertoire.

CONCLUSIONS

Our study establishes for the first time a critical control for differentiation and maturation of adult human T cells from HPCs by concomitant regulation of IL-7 and pre-TCR signaling.

Detection of Skeletal Lesions by Whole Body Multidetector Computed Tomography in Multiple Myeloma has no Impact on Long-Term Outcomes Post Autologous Hematopoietic Cell Transplantation

BACKGROUND

Multiple myeloma (MM), a plasma cell malignancy, is the most common cancer to involve the skeleton. Skeletal related events such as pathologic fractures and lytic bone lesions have been associated with poor prognosis. Whole body multidetector computed tomography (WBCT) has been shown to be the most sensitive imaging modality in detecting small osteolytic lesions (< 5 mm) in the spine. The significance of lytic lesions detected only by CT is unknown as is their impact on overall survival of MM. The aim of this study was to evaluate the impact of lytic bone lesions seen only by WBCT on progression free survival (PFS) and overall survival (OS) in MM patients after hematopoietic cell transplantation (HCT).

METHODS

We evaluated 72 patients who had WBCT and conventional radiographic skeletal survey (CSS) after initial or salvage chemotherapy prior to HCT.

RESULTS

Forty-one patients (57%) had more findings on WBCT than CSS, 31 patients (43%) had no differences in the two imaging techniques, 9 patients had no bone lesions on either modality, and 5 patients had lesions only identified by WBCT and not on CSS. PFS and OS were similar in patients with lesions seen by CSS irrespective of whether additional lesions were noted by WBCT; similarly, in patients without lesions on CSS, OS and PFS were better than patients with lytic lesions, but detection of occult lesions by WBCT did not adversely affect PFS or OS.

CONCLUSIONS

Our study shows that although WBCT is more sensitive in defining existing myelomatous bony disease in MM, these additional findings may not have any impact on PFS and OS of MM patients. Only patients without any bone lesions on conventional skeletal survey had significantly better PFS and OS. This suggests CSS remains the gold standard for evaluating myeloma bone disease.

Lenalidomide after stem-cell transplantation for multiple myeloma

BACKGROUND

Data are lacking on whether lenalidomide maintenance therapy prolongs the time to disease progression after autologous hematopoietic stem-cell transplantation in patients with multiple myeloma.

METHODS

Between April 2005 and July 2009, we randomly assigned 460 patients who were younger than 71 years of age and had stable disease or a marginal, partial, or complete response 100 days after undergoing stem-cell transplantation to lenalidomide or placebo, which was administered until disease progression. The starting dose of lenalidomide was 10 mg per day (range, 5 to 15).

RESULTS

The study-drug assignments were unblinded in 2009, when a planned interim analysis showed a significantly longer time to disease progression in the lenalidomide group. At unblinding, 20% of patients who received lenalidomide and 44% of patients who received placebo had progressive disease or had died (P<0.001); of the remaining 128 patients who received placebo and who did not have progressive disease, 86 crossed over to lenalidomide. At a median follow-up of 34 months, 86 of 231 patients who received lenalidomide (37%) and 132 of 229 patients who received placebo (58%) had disease progression or had died. The median time to progression was 46 months in the lenalidomide group and 27 months in the placebo group (P<0.001). A total of 35 patients who received lenalidomide (15%) and 53 patients who received placebo (23%) died (P=0.03). More grade 3 or 4 hematologic adverse events and grade 3 nonhematologic adverse events occurred in patients who received lenalidomide (P<0.001 for both comparisons). Second primary cancers occurred in 18 patients who received lenalidomide (8%) and 6 patients who received placebo (3%).

CONCLUSIONS

Lenalidomide maintenance therapy, initiated at day 100 after hematopoietic stem-cell transplantation, was associated with more toxicity and second cancers but a significantly longer time to disease progression and significantly improved overall survival among patients with myeloma. (Funded by the National Cancer Institute; ClinicalTrials.gov number, NCT00114101.).

Selective purging of human multiple myeloma cells from autologous stem cell transplantation grafts using oncolytic myxoma virus

Autologous stem cell transplantation and novel therapies have improved overall survival of patients with multiple myeloma; however, most patients relapse and eventually succumb to their disease. Evidence indicates that residual cancer cells contaminate autologous grafts and may contribute to early relapses after autologous stem cell transplantation. Here, we demonstrate that ex vivo treatment with an oncolytic poxvirus called myxoma virus results in specific elimination of human myeloma cells by inducing rapid cellular apoptosis while fully sparing normal hematopoietic stem and progenitor cells. The specificity of this elimination is based on strong binding of the virus to myeloma cells coupled with an inability of the virus to bind or infect CD34(+) hematopoietic stem and progenitor cells. These 2 features allow myxoma to readily identify and distinguish even low levels of myeloma cells in complex mixtures. This ex vivo rabbit-specific oncolytic poxvirus called myxoma virus treatment also effectively inhibits systemic in vivo engraftment of human myeloma cells into immunodeficient mice and results in efficient elimination of primary CD138(+) myeloma cells contaminating patient hematopoietic cell products. We conclude that ex vivo myxoma treatment represents a safe and effective method to selectively eliminate myeloma cells from hematopoietic autografts before reinfusion.

Extramedullary disease in plasma cell myeloma: the iceberg phenomenon

Extramedullary (EM) plasmacytomas (EMPs) that are not progression of intramedullary (IM) plasma cell myeloma (PCM) are usually indolent. In contrast, EM spread of IM PCM is associated with a poor prognosis. The recently introduced Durie-Salmon PLUS staging system includes EM disease in the poor prognosis category. One study noted an increase in EM disease both at diagnosis and during follow-up of PCM in 2000-2007 compared with previous years raising concerns that adoption of novel agents (thalidomide, lenalidomide and bortezomib) and greater use of hematopoietic cell transplantation (HCT) might be contributory to this. It is uncertain if this is a true increase or merely greater detection due to the increasing use of more sensitive imaging techniques (computerized tomography, magnetic resonance imaging and ¹⁸F-fluorodeoxyglucose positron emission tomography) or a reflection of the evolving natural history of PCM in an era when patients are living longer (median overall survival before 1996 was 29.9 months vs 44.8 months after 1996). Recent studies suggest there are important biological differences between PCM with or without EM spread that are offering clues that might explain the propensity for dissemination and a more aggressive clinical course. For example, EM relapse in PCM with and without deletion 13 was 30.8 vs 5.6%, suggesting the biology of a plasma cell subclone before HCT can affect the nature of the relapse after HCT. This article will explore the clinical, biological and treatment implications of EM spread of PCM. In addition, the impact of extramedullary disease on the outcomes of autologous and allogeneic HCT for PCM will be analyzed. Allogeneic HCT early in the course of high-risk PCM with EM disease is a consideration since graft vs myeloma effects may be essential to achieve maximal survival benefits.

The enzymatic activity of human aldehyde dehydrogenases 1A2 and 2 (ALDH1A2 and ALDH2) is detected by Aldefluor, inhibited by diethylaminobenzaldehyde and has significant effects on cell proliferation and drug resistance

There has been a new interest in using aldehyde dehydrogenase (ALDH) activity as one marker for stem cells since the Aldefluor flow cytometry-based assay has become available. Diethylaminobenzaldehyde (DEAB), used in the Aldeflour assay, has been considered a specific inhibitor for ALDH1A1 isoform. In this study, we explore the effects of human ALDH isoenzymes, ALDH1A2 and ALDH2, on drug resistance and proliferation, and the specificity of DEAB as an inhibitor. We also screened for the expression of 19 ALDH isoenzymes in K562 cells using TaqMan Low Density Array (TLDA). We used lentiviral vectors containing the full cDNA length of either ALDH2 or ALDH1A2 to over express the enzymes in K562 leukemia and H1299 lung cancer cell lines. Successful expression was measured by activity assay, Western blot, RT-PCR, and Aldefluor assay. Both cell lines, with either ALDH1A2 or ALDH2, exhibited higher cell proliferation rates, higher clonal efficiency, and increased drug resistance to 4-hydroperoxycyclophosphamide and doxorubicin. In order to study the specificity of known ALDH activity inhibitors, DEAB and disulfiram, we incubated each cell line with either inhibitor and measured the remaining ALDH enzymatic activity. Both inhibitors reduced ALDH activity of both isoenzymes by 65-90%. Furthermore, our TLDA results revealed that ALDH1, ALDH7, ALDH3 and ALDH8 are expressed in K562 cells. We conclude that DEAB is not a specific inhibitor for ALDH1A1 and that Aldefluor assay is not specific for ALDH1A1 activity. In addition, other ALDH isoenzymes seem to play a major role in the biology and drug resistance of various malignant cells.

Severe neutropenia following a prolonged course of vancomycin that progressed to agranulocytosis with drug reexposure

OBJECTIVE

To report a case of severe neutropenia after discontinuing prolonged treatment with vancomycin that progressed to agranulocytosis with vancomycin reexposure.

CASE SUMMARY

A 78-year-old woman presented with severe neutropenia (absolute neutrophil count [ANC] 37 cells/μL) and hypocellular bone marrow with absence of myeloid elements 8 weeks after discontinuing a 3-week treatment course of vancomycin 750 mg every 12 hours. Filgrastim 300 μg daily was started for neutropenia and vancomycin 750 mg every 12 hours and aztreonam 1 g every 8 hours were initiated for catheter-related acute thrombophlebitis of the upper extremity. The patient's ANC decreased to 10 cells/μL within 3 days of starting vancomycin. We suspected an autoimmune process, potentially related to vancomycin exposure, and began treatment with methylprednisolone 1 mg/kg daily. The ANC precipitously dropped to 0 cells/μL despite treatment with steroids and an increased filgrastim dose of 480 μg/day. All antibiotics were discontinued on the fifth day of hospitalization. Within 48 hours, her neutrophil count showed recovery (white blood cell count 500 cells/μL; 10% neutrophils).

DISCUSSION

Idiosyncratic drug-induced agranulocytosis is an uncommon phenomenon but is often associated with serious consequences such as sepsis. We believe this case is unique because of the unusually late neutropenia discovered several weeks after finishing a prolonged course of vancomycin. Furthermore, agranulocytosis developed after unintentional rechallenge with vancomycin. According to the Naranjo probability scale, this case illustrates a probable adverse event caused by vancomycin.

CONCLUSIONS

This case demonstrates a serious adverse event potentially associated with vancomycin use, and calls attention to the safety of rechallenging with vancomycin during a possible drug-induced neutropenia.

Plerixafor in non-Hodgkin’s lymphoma and multiple myeloma patients undergoing autologous stem cell transplantation

Autologous stem cell transplantation (ASCT) is the standard of care for multiple myeloma (MM) and relapsing non-Hodgkin’s lymphoma (NHL) patients. Peripheral blood stem cells (PBSC) have become the main source of grafts for ASCT due to several advantages over bone marrow grafts. Poor PBSC mobilization and inadequate collection of CD34+ cell dose for safe engraftment is a reality for significant proportion of these patients. For this review, we conducted a PubMed search using the titles plerixafor and AMD3100 as well as poor stem cell mobilization. English-language articles were selected and data were extracted with focus on clinical studies of PBSC mobilization in MM and NHL patients. We discuss predictors of poor PBSC mobilization, the impact of poor mobilization on ASCT outcomes, the available agents that have been routinely used to enhance mobilization to achieve optimal CD34+ cell dose, and the role of plerixafor, the first CXCR4 antagonist to be approved for stem cell mobilization. Studies have shown that plerixafor is effective and safe when given with G-CSF either upfront or as a rescue for patients with MM or NHL. Currently, more patients are getting transplanted because of plerixafor. The challenge now is how to use the drug in the most cost effective way. Several scenarios on how to use the drug in proven or predicted poor mobilizers are proposed in this manuscript; however, validation for some of these approaches is still needed.

Plerixafor in non-Hodgkin’s lymphoma and multiple myeloma patients undergoing autologous stem cell transplantation

Autologous stem cell transplantation (ASCT) is the standard of care for multiple myeloma (MM) and relapsing non-Hodgkin’s lymphoma (NHL) patients. Peripheral blood stem cells (PBSC) have become the main source of grafts for ASCT due to several advantages over bone marrow grafts. Poor PBSC mobilization and inadequate collection of CD34+ cell dose for safe engraftment is a reality for significant proportion of these patients. For this review, we conducted a PubMed search using the titles plerixafor and AMD3100 as well as poor stem cell mobilization. English-language articles were selected and data were extracted with focus on clinical studies of PBSC mobilization in MM and NHL patients. We discuss predictors of poor PBSC mobilization, the impact of poor mobilization on ASCT outcomes, the available agents that have been routinely used to enhance mobilization to achieve optimal CD34+ cell dose, and the role of plerixafor, the first CXCR4 antagonist to be approved for stem cell mobilization. Studies have shown that plerixafor is effective and safe when given with G-CSF either upfront or as a rescue for patients with MM or NHL. Currently, more patients are getting transplanted because of plerixafor. The challenge now is how to use the drug in the most cost effective way. Several scenarios on how to use the drug in proven or predicted poor mobilizers are proposed in this manuscript; however, validation for some of these approaches is still needed.

Abstract LB-157: Overcoming T-regulatory effects towards developing a more effective immunotherapy targeting multiple myeloma

Recent progress in dendritic cell (DC) and T cell therapies has offered a new avenue in treating multiple myeloma (MM). We have reported that MM patients' DCs cannot effectively present MM antigens and, instead, preferrentially activate T regulatory cells (Tregs). Furthermore, the MM cells actively suppress patients' DC and T cell functions (Han et al. 2008 Mol Ther. 16, 269–279). Therefore, an effective immunotherapy must overcome immune tolerance to the cancer cells and effectively expand functional MM-specific effector cells. To obtain critical data about MM patient's immune status, a longitudinal study of Treg cells before and after treatments of twenty MM patients was conducted. Patients' bone marrow (BM) and peripheral blood (PB) specimens were collected in the first visit and the follow up visits during treatment. Treg cell populations were examined using antibodies against CD4, CD25, CD127 and Foxp3. At the same time, naïve versus memory phenotype was assessed using antibodies against CD45RA, CCR7 and CD27. Besides the above markers, the surface molecule KLRG1 reflecting T cell senescence and longivity was also detected by flow cytometry. Analysis of Tregs at different time points showed a clear trend of gradual increase in Treg population both in the BM and PB of the MM patients; compared with healthy donors, MM patients' Tregs expand more than two to three folds. Surface marker analysis suggests that the expanded Tregs are mostly memory effector cells, which coincides with a decrease in the ratio of naïve Tregs. Analysis of MM-specific T cell responses by examining effector cytokines and cytolytic activities against autologous tumor cells revealed that BM contained more cytotoxic T cells than did PB. Increased expansion of MM-specific immune effector cells in culture was observed when Treg activities were suppressed using various immune modulators. Further understanding of Treg-mediated cancer tolerance will be essential to develop clinically more effective immunotherapy towards improved survival of MM patients.

Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-157. doi:10.1158/1538-7445.AM2011-LB-157