ALBERT

Description: Abstract 4975 Background: Our group has developed a peptide referred to as HYD1 which binds VLA-4 integrin/CD44 containing complex and induces necrotic cell death in myeloma cells (Nair et al Mol Cancer Ther 2009, Emmons et al, Mol Cancer Ther, 2011). Furthermore, we previously demonstrated in a small subset of MM patients that HYD1 was more active in specimens obtained from relapsed/refractory patients, a finding that correlated with VLA-4 expression. The frequency of expression and prognostic significance of two key surface markers VLA4 (very late antigen 4) and CD44 in patients with MM remains poorly defined. Methods: We retrospectively reviewed records of patients with MM who had a complete flow cytometry panel (which includes assessment for CD44 and VLA4) at Moffitt Cancer Center between 1/1/2004 and 12/31/2009. CD44 and VLA4 were gated by CD138 expression and we categorized expression as negative, dim, moderate or bright. We collected demographic information, disease related characteristics (including ISS stage, cytogenetics, and baseline laboratory testing) and treatment and outcomes related data (prior therapies, response to first line therapy, follow up and vital status). Responses were per IMWG criteria and for the purpose of this study, a partial remission or better qualified as a response to therapy. High risk cytogenetics (HRC) was defined by the presence of one of the following; 17p deletion, t(4;14), t(14;16) and 13q deletion by metaphase cytogenetics. The study was approved by the IRB at the University of South Florida. Results: A four color flow cytometry panel was available for review on 101 myeloma patients including 57 males, median age at diagnosis was 60 (range 39–83) years. The percentage of ISS stage I, II and III at diagnosis was 36. 4%, 34. 8% and 28. 8% respectively and 28. 7% of the patients had HRC. At the time of the flow panel, 32 patients (31. 7%) were untreated and overall patients had a median of 3 prior therapies (range 0–11). 52 patients (51. 5%), 37 (36. 6%) and 12 (11. 9%) had no, dim or moderate CD44 expression respectively while 26 (26. 3%), 68 (68. 7%) and 5 (5. 1%) had no, dim or moderate VLA4 expression respectively. Subsequently both were sub-grouped according to presence (dim or greater) or absence of expression. A correlation between the expression of CD44 and VLA4 was noted (Fisher's exact p 〈 0. 001), 45 patients express both markers, 24 express neither markers, 28 express VLA4 but not CD44 while only 4 express CD44 and not VLA4 (p

Description: Purpose: Drug resistance is the greatest obstacle to the successful treatment of multiple myeloma (MM). We investigated whether the clinical XPO1 inhibitor selinexor (KPT-330), when combined with bortezomib or carfilzomib, could overcome proteasome inhibitor (PI) resistance in myeloma. Experimental Design: PI-resistant human MM cell lines 8226-B25 and U266-PSR were treated with the XPO1 inhibitors selinexor or KOS-2464 in combination with bortezomib or carfilzomib and assayed for apoptosis and viability. Mice challenged with PI-resistant human MM cells (U266-PSR) were treated with selinexor +/- bortezomib. CD138+/light-chain+ MM cells from PI-refractory MM patients were treated with selinexor +/- bortezomib or selinexor +/- carfilzomib and assayed for apoptosis. All experiments were compared to the standard of care, bortezomib therapy. IkBα-protein was assayed by Western blot and immunofluorescence microscopy and IkBα-NFkB-complex formation by proximity ligation assay. IkBα protein knockdown in human MM cells by siRNA was performed to determine the mechanism of selinexor inhibitor action. Further analysis of selinexor/bortezomib treatment on intra-cellular protein levels and intra-cellular localization was performed by lysine and N-terminal labeling with six-plex tandem mass tags (heavy isotope) and assayed by LC-MS/MS discovery proteomics. Results: Selinexor in combination with bortezomib or carfilzomib decreased viability and induced apoptosis in PI-resistant MM cells. Resistant MM cell lines were up to 10-fold resistant to single agent bortezomib or carfilzomib when compared to parental cells. The combination of the XPO1 inhibitors selinexor or KOS-2464 sensitized drug resistant cells to bortezomib (P 〈 0.02) and carfilzomib (P 〈 0.005) when compared to single agents. Selinexor and bortezomib inhibited PI-resistant MM tumor growth and increased survival with minimal toxicity in NOD/SCID-g mice. Bone marrow mononuclear cells isolated and treated with selinexor or KOS-2464 and bortezomib or carfilzomib from newly diagnosed (n=8), relapsed (n=5), and bortezomib (n=8) and carfilzomib (n=6) refractory MM patient samples were all sensitized by selinexor and KOS-2464 to bortezomib (P 〈 0.043) and carfilzomib (P 〈 0.044) as shown by increased apoptosis. Normal, non-myeloma CD138/light-chain double-negative patient cells were not sensitized to apoptosis by XPO1 inhibitors. Immunofluorescence microscopy of IkBα in 8226-B25 PI-resistant cells showed an increase in IkBα after treatment with selinexor/bortezomib as compared with vehicle control or single agent bortezomib or selinexor. Nuclear IκBα was also increased by selinexor treatment. IkBα protein expression was increased by bortezomib (70%) and selinexor (50%) versus control. The selinexor/bortezomib combination increased IkBα protein (212%) as compared to vehicle control or single agent bortezomib or selinexor. Similar results were found in drug-naïve 8226 and U226 cells, as well as PI-resistant 8226-B25 and U225-PSR cells. The increase in nuclear IkBα after selinexor treatment was confirmed by ImageStream flow cytometry. Selinexor/bortezomib therapy significantly increased IkBα-NFkB-complexes in PI-resistant MM cells. Selinexor in combination with bortezomib increased proximity co-localization of NFkB and IkBα without affecting XPO1 protein expression after 4 hours of drug treatment. Analysis of the number of NFkB-IkBα foci/binding showed that selinexor/bortezomib increased the number of foci in the nucleus versus untreated control or single agent selinexor or bortezomib (P ≤ 0.00077). IkBα knockdown reduced selinexor-induced cytotoxicity in both IM-9 (9.5-fold) and 8226 (12.3 to 25.4-fold) human MM cells. Intracellular protein analysis by heavy isotope labeling and LC-MS/MS showed changes in several signaling pathways including p53, MAPK, VEGF and angiopoietin, IL-1, HMGB1/TLR and APRIL and BAFF as well as those related to NFkB signaling. Conclusion: Selinexor, when used in combination with bortezomib or carfilzomib has the potential to overcome PI drug resistance in MM. Disclosures Kashyap: Pharma: Employment. Landesman:Karyopharm Therapeutics: Employment. Kauffman:Karyopharm: Employment, Equity Ownership. Shacham:Karyopharm: Employment, Equity Ownership.

Description: Background Twenty four-hour urine collection remains one of the most crucial tools for the diagnosis and monitoring of proteinuria and quantification of urinary monoclonal protein in patients with plasma cell dyscrasias (PCD) even though it is cumbersome. Nephrology guidelines recommend replacement of 24-hour urine collection with a spot urine protein/creatinine (Pr/Cr) ratio for the measurement of proteinuria. However, only limited data exist regarding accuracy of spot urine Pr/Cr ratio in patients with PCD and utility of this measure to estimate urinary paraprotein remains uncertain. We conducted a prospective study evaluating the role of spot urine Pr/Cr ratio in patients with PCD. Methods From 04/2012 to 05/2013, a total of 120 PCD patients were prospectively enrolled at Moffitt Cancer Center. Oliguric patients or those requiring dialysis were ineligible. Spot urine was collected on the same day as 24-hour urine collection. Spot urine Pr/Cr ratios were compared to 24-hour urine collections with regard to the amount of (1) total protein and (2) monoclonal protein (M-spike). Results Eighty four out of 120 patients (70%) were evaluable (17 did not provide spot urine samples; no Pr/Cr ratios available in 11; protein below the level of detection in 7; and one without 24-hour urine collection). Evaluable patients had a median age of 68 (range, 36 - 90) years, 63% were male, and 85% were Caucasian. Primary diagnoses were myeloma (n=74; 88%), amyloidosis (n=4), multiple plasmacytomas (n=2), solitary plasmactyoma (n=1) and MGUS (n=3). Prior therapies included chemotherapy in 95% and autologous transplant in 45%. Comorbidities included hypertension (48%), chronic kidney disease (30%), diabetes (15%), coronary artery disease (8%), atrial fibrillation (7%) and congestive heart failure (2%). The median serum creatinine was 0.9 mg/dL (range, 0.5 - 5.1). The median spot urine Pr/Cr ratio was 137 mg/g creatinine (range, 26 - 21,447). The median 24-hour urine protein was 120 mg/24h (range, 27 - 15,092), and the median urine M-spike was 1.2 mg (range, 0 - 8,099). More than half of spot urine samples were collected in the morning (59%). There were strong correlations between (1) spot urine Pr/Cr ratio and 24-hour total urine protein (Spearman correlation coefficient=0.91, p 〈 0.0001), and (2) spot urine Pr/Cr ratio and 24-hour urine M-spike (Spearman correlation coefficient=0.91, p 〈 0.0001). The timing of spot urine sample collection had no significant effects on the correlations (p = 0.46 and 0.95 by Wilcoxon rank-sum test). Conclusions Spot urine Pr/Cr ratio strongly correlates with degrees of proteinuria measured in 24-hour urine collection and may also predict the quantity of urine M-spike in non-oliguric PCD population. Spot urine Pr/Cr ratio is a potentially useful marker as a screening tool or an alternative semi-quantitative measure for rapid estimation of proteinuria which may be used for longitudinal patient follow-up in lieu of cumbersome repeated 24-hour collections. Disclosures: No relevant conflicts of interest to declare.

Description: Relapse of malignancy is frequent in patients transplanted with advanced diseases. There is a relationship between higher Bu exposure and lower risk of relapse, but also higher transplant-related mortality, and data indicated the maximum tolerated daily Bu AUC is 〈 6000 microMol/min when Bu is used in combination with cyclophosphamide (Cy). To reduce transplant-related mortality, Flu has been substituted for Cy in many transplant centers. We hypothesized that pharmacokinetics-targeting of IV Bu, which results in a predictable systemic exposure, would produce values of tolerable Bu AUC that are higher for BuFlu than for BuCy. Our standard HCT regimen since July 2004 consists of once daily IV BuFlu where fludarabine 40 mg/m2 is given intravenously daily for four days and each infusion is followed immediately by an initial IV Bu dose of 130 mg/m2. Pharmacokinetic analysis is performed after the first infusion of busulfan; the goal is to adjust the busulfan doses for days 3 and 4 to achieve an average exposure targeted to an AUC of 4500–5600 microMol/min. Outcomes for the first sixty-nine patients were analyzed. Thirty-nine of 63 (62%) evaluable patients had their Bu doses adjusted, 30 increased [median adjustment 50% (8 – 175%)], and 9 decreased [median 30% (11 – 60%)], while 24 (38%) pts had an AUC within the desired range without adjustment. Most of the patients (98%) had hematological malignancies and 73% had high CIBMTR risk, median age was 48 (22–68) years, donors were HLA-identical siblings (33), matched (23) or mismatched unrelated donors (13). With a median patient follow-up of 392 (248 – 707) days, the non-relapse mortality was 4% at 100 days and 17% at one year. The K-M estimates of survival and event-free survival are 88%±4% and 83%±5% at 100 days, and 61%±6% and 51%±6% at 1 year, respectively. Subsequently, as part of a prospective, targeted AUC-dose finding trial, 20 patients received an initial Bu dose of 170 mg/m2 with subsequent doses targeted to achieve a 4-day average AUC of 5400–6600 microMol/min. Pharmacokinetic analysis was performed after the first and fourth infusion of busulfan. All patients had hematologic malignancies, 65% had high CIBMTR risk, median age was 48 (22 – 61) years, donors were HLA-A, B, C, DRB1, DQB1 matched siblings (11) or matched unrelated donors (9). Thirteen (65%) patients had their doses adjusted, six had it increased [median 37.1% (35.6 – 61.9 %)] and seven decreased [median 41.6% (18.3 – 55.2%)], while seven patients had an AUC within the desired range without adjustment. With a median follow-up of 111 (range 21–312) days, the 100-day K-M estimates of survival are 88%±8% and event-free survival 83%±9%. The complete observation of 100-day safety, relapse and survival will be presented at the meeting and data will determine further AUC escalation.

Description: Preclinical studies suggest that neoplastic cells may be particularly sensitive to simultaneous interruption of cell-cycle and survival signaling pathways. In accord with this concept, we have shown that flavopiridol (F), a CDK inhibitor, interacts with bortezomib (B), a proteasome inhibitor, to induce mitochondrial injury and apoptosis in human leukemia, myeloma, and lymphoma cells (Dai et al, Oncogene22:7108, 2003; Dai et al, Blood104:509, 2004). These actions were associated with inhibition of NF-kappaB DNA binding, increased expression of phospho-JNK, and downregulation of XIAP and Mcl-1. Based on these findings, a phase I trial has been initiated to identify appropriate doses of B+F for further investigation. Eligible patients (pts) include those with multiple myeloma or indolent B-cell neoplasms, and recurrent or refractory disease following at least 1 prior systemic therapy (excluding allogeneic stem cell transplantation). In the initial stage of the trial, pts received B (iv push) immediately followed by F bolus (1- hour infusion) on d1, 4, 8, and 11 out of a 21-day (d) cycle. Dose levels were, in mg/m2 (B/F): 1.0/15, 1.3/15, 1.3/22, 1.3/30, 1.3/40, 1.3/50, and 1.3/60. Subsequently, a “hybrid” F infusion schedule (30 minute load followed by a 4-hour infusion) was adopted based on evidence of activity of this schedule in chronic lymphocytic leukemia. With the hybrid schedule, all pts receive B (iv push) 1.3 mg/m2 on d1, 4, 8 and 11. Targeted F dose levels using the hybrid schedule are (Fload/Finfusion; mg/m2): 20/20 on d1 and 8; 30/30 on d1 and 8; 30/50 on d1 and 8; 30/30 on d1, 4, 8 and 11; 30/50 on d1, 4, 8 and 11. Dose limiting toxicity (DLT) is defined as NCI CTCAE grade 4 ANC/platelets for 〉 1 week or grade ≥ 3 non-heme toxicity. 38 pts have been enrolled. 29 pts were treated at 7 dose levels with the bolus schedule, after which development of the hybrid schedule was begun. With the hybrid schedule, 11 pts have been treated at 3 dose levels. To date, one DLT (grade 3 lower back pain) was observed at level 5 of the bolus schedule and one DLT (grade 3 fatigue) was seen at the 1st hybrid dose level. The MTD of the hybrid schedule has not been reached. Non-DLT toxicities include herpes zoster (2 disseminated), peripheral neuropathy, fatigue, postural hypotension, syncope, diarrhea and ≤ grade 3 cytopenias. Of 35 pts evaluable for response, there have been 2 complete responses (1 lymphoma and 1 mantle cell lymphoma), 7 partial responses (5 myeloma and 2 lymphoma), 3 minor responses (2 myeloma and 1 extramedullary plasmacytoma), 15 patients with stable disease (5 myeloma, 7 lymphoma, 1 Waldenstrom’s and 2 mantle cell lymphomas). Of the 3 pts who had received prior bortezomib, 2 had minor responses and 1 had disease progression. To date, hyperacute tumor lysis has not occurred with the hybrid schedule, but aggressive prophylaxis and monitoring are integral to the treatment plan. Correlative laboratory studies involving bone marrow CD138+ cells from patients with myeloma revealed a reduction in post-treatment NF-kappaB nuclear localization in 4 of 5 evaluable patients. Variable effects on myeloma cell expression of phospho-JNK, Mcl-1, and XIAP have been observed. Collectively, these findings indicate that a regimen combining bortezomib and flavopiridol, including the use of a hybrid flavopiridol schedule, is well tolerated in patients with progressive B-cell malignancies, and has clear activity in some patients refractory to standard therapy. Pending identification of the MTD and RPTD (recommended phase II dose), phase II evaluation of this therapeutic strategy should define its activity more definitively.

Description: Background: Approximately 25% of patients with newly diagnosed (MM) fail to respond and progress while receiving conventional induction. As a result, these patients have primary refractory disease. Even though these patients still benefit from HD chemotherapy, their PFS ranges from 4–8 months, while OS is approximately 12 months. PCL accounts for approx. 2% of newly diagnosed MM patients and represents the most aggressive form of disase. These patients often do not respond to standard systemic cytotoxic therapies and their median survival is less than 12 months. Therefore, novel treatment approaches are paramount for patients with primary refractory MM and PCL. The proteasome inhibitor BTZ has been shown to sensitize myeloma cells to melphalan both in vitro and in vivo, but the mechanism is not well understood. In this study we examine the effects of BTZ, followed by BTZ and HDMel as conditioning regimen for TanPSCT in this poor-risk group. Methods: Patients with primary refractory MM or PCL received 2 cycles of BTZ at 1.3 mg/m2. followed by HD Mel (200 mg/m2) and one dose of BTZ at 0.7 mg/m2, 1.0 mg/m2 or 1.3 mg/m2, as a conditioning regimen prior to TanPSCT. The dose of BTZ was given immediately after the last dose of HD Mel. Bone marrow(BM) samples were collected at baseline, on day 4 and after 2 cycles of BTZ, and at 3 months after TanPSCT, for GEP and Fanconi anemia(FA) pathway genes assessment. Results: To date, 17 patients have been enrolled and treated, and 11 patients are evaluable for response. Median age is 59 years (46–70) with the following myeloma distribution: 55% IgA and 45% IgG. FISH analysis showed the following: del 13q (44%), t (4; 14) (11%), t (11; 14) (11%), trisomy 11 (11%), and polyploid (11%); standard karyotype was normal in 88% of patients and complex karyotype in 12%. Median time to WBC engraftment (days) was 13 and 12 after the first and second transplant, respectively. Median time to plt engraftment (days) was 20 and 17, after the first and second transplant, respectively. There were no dose limiting toxicities. Observed grade 3 toxicities were related to the conditioning regimen and similar to those observed with HDMel alone. One patient developed diffuse alveolar hemorrhage after the first cycle of BTZ, which resolved, but was removed from study. After 2 cycles of BTZ, 45% of patients achieved PR, and 55% had stable disease. Overall response rate at 3 months from the second transplant increased to 90%(CR=36%,VGPR=27% andPR=27%). Only 1 patient developed progressive disease after the first transplant. Evaluations of BM samples by GEP and FA pathway gene expression are underway. Conclusions: Single agent BTZ induced responses in 45% and the combination of HD Mel and BTZ as conditioning regimen for TanPSCT was well tolerated and improved response rates to 90%. These early results suggest that this regimen is very active in this poor-risk group. Evaluation of collected BM samples for GEP and FA pathway genes may provide important insight into the mechanisms associated with the observed synergy between BTZ and HD Mel. A Phase II study is underway.