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Abstract Lenalidomide (Len), an analog of thalidomide (thal) is a novel, oral, immunomodulatory agent that is effective against multiple myeloma (MM). In 2 prospective, randomized, double-blind, placebo-controlled Phase III trials. Len with dexamethasone (Dex) induced a significantly higher overall response rate (OR) and complete remission rate (CR), as well as longer time-to-progression (TTP) in comparison with Dex alone. This prospective analysis assessed whether prior thalidomide exposure might induce subsequent resistance to Len/Dex. We evaluated 704 patients (pts) from both trials (MM009, MM010) who had relapsed or refractory multiple myeloma, had not been resistant to Dex and were randomized to receive either oral Len (25 mg daily for 3 weeks every 4 weeks) plus Dex (40 mg on days 1–4, 9–12, 17–20 every 4 weeks for 4 cycles) or placebo plus Dex. Two hundred seventy four pts (39%) received prior thal, while 430 (61%) had not. The prior thal exposed pts and thal-naive pts were similar in regard to age, Beta-2-microglobulin, hemoglobin, serum M protein, albumin and history of previous transplantation. The frequency of deep venous thrombosis and pulmonary embolism (DVT/PE) with prior thal exposure was higher at 14% with Len/Dex than 4% with Dex alone (p < 0.01). However, the frequency of DVT/PE with no prior thal exposure was similar at 8% with Len/Dex to 6% with Dex alone (p = 0.49). In the prior thal pts, severe neuropathy occurred in 4% with Len/Dex, not significantly different from the 1% with Dex alone (p=0.2). The pooled data from all 704 pts showed that pts treated with Len/Dex, compared with those treated with Dex alone, had superior median Time-To-Progression (TTP) (48 vs 20 weeks) and OR (60% vs 22%, p <0.001). Similarly, among the subgroups exposed or not exposed to thal, Len/Dex was superior to Dex alone in OR and TTP. For the 126 patients who received prior thal, the OR with Len/Dex was significantly less (43%) among 54 Pts resistant to thal than that observed for 72 Pts who had been sensitive to thal (63%, p < 0.05). Multivariate analysis using Cox proportion hazards model indicated that after controlling for treatment (Len/Dex vs Dex) and baseline disease characteristics, independent and significant predictors of shorter TTP included prior thal exposure, duration of myeloma and number of prior therapies. Len in combination with Dex was more effective than Dex in patients with relapsed or refractory multiple myeloma despite prior thal exposure. Results with Len/Dex were superior for those not exposed to thal, suggesting some, but not complete, cross resistance between Len and thal. Len/Dex vs Dex with or without Prior Thal Thal (N=274) No Thal (N=430) LD D p LD D p Intent-to-Treat (n) 126 148 227 203 TTP (med. weeks) 36.9 19.9 <.001 61.3 20.4 <.001 OR (%) 54.0 14.9 <.001 63.4 27.6 <.001 PR (%) 42.1 12.8 <.001 32.2 23.2 <.05 NCR (%) 4.0 0.7 <.001 13.2 2.0 <.001 CR (%) 7.9 1.4 <.01 18.1 2.5 <.001

Abstract Background: Patients with early stage myeloma are typically observed without therapy until symptomatic disease occurs. We have reported early results of therapy with single-agent thalidomide as initial therapy for early stage multiple myeloma in an attempt to delay progression to symptomatic disease (Leukemia2003;17:775–9). We now report the long-term results of this phase II trial. Methods: Thirty-one patients with smoldering or indolent multiple myeloma were enrolled between April 1999–March 2002. All pts had bone marrow (BM) plasma cells >=10% and measurable disease defined as serum monoclonal (M) protein >=2gm/dL and/or urine M protein >=400mg/24 hours. Two patients were deemed ineligible because they were found to have received prior therapy for myeloma and were excluded from analysis. Thalidomide was initiated at a dose of 200 mg/day and increased as tolerated by 200 mg/day every 2 weeks to a maximum dose of 800 mg/day. The dose of thalidomide was decreased as needed to minimize toxicity. Treatment was continued until disease progression or serious toxicity, except for patients achieving less than a minor response (<25% paraprotein reduction) to therapy in whom therapy was stopped at one year. Response was defined as a decrease in serum and urine monoclonal (M) protein by 50% or higher. If the serum M protein was unmeasurable, a 90% or higher decrease in urine M protein was required. Responses need to be confirmed at least 4 weeks apart. Results: Ten patients (34%) had indolent myeloma, including 4 patients with lytic bone lesions, 3 patients with anemia (Hb <11gm/dL), and 3 patients with both anemia and lytic bone lesions. Median follow up of living patients is 5.6 years (range, 4.0–7.1 years). Of the twenty-nine eligible patients, ten (34%) had a partial response to therapy with at least 50% or greater reduction in serum and urine monoclonal (M) protein. Three patients are still on study and receiving therapy. The remaining have gone off-study: seven patients (27%)had progressive disease while on therapy; other reasons for ending study treatment included completed therapy per protocol (2 pts), patient refusal (2pts), toxicity (8 pts), alternate treatment (3 pts), other medical problems (1 pt), died on study (1 pt), and other (2 pts). The median time to progression (TTP) was 3.2 years (95% CI 2.1–5.6 yrs). Median progression free survival (PFS) was 3.0 yrs (95% CI 2.0–5.1 yrs). Median overall survival has not been reached; 5 year survival rate by the Kaplan Meier method is 60%. Major grade 3–4 non-hematologic adverse events at any time during therapy were noted in 34% of patients; this includes 14% with grade 4 toxicity. Grade 3–4 toxicities occurring in more than one patient include neuropathy (2 pts) and sinus bradycardia (2 pts). Conclusions: Thalidomide has activity in asymptomatic myeloma. This approach must be further tested in randomized trials to determine if the survival estimates are superior to observation. Given the activity of thalidomide, trials are also needed with lenalidomide.

Abstract Acute Lymphoblastic Leukemia (ALL) is the most common malignancy observed in the pediatric population. Recent genomic studies have made considerable strides in improving our understanding of the molecular pathogenesis of pediatric B-cell ALL. This includes the discovery of recurrent somatic alterations targeting B-cell transcription factors, mutations in epigenetic regulators, and oncogenic mutations which activate signaling effectors, including in Ph-like B-ALL. However, the molecular pathogenesis of adult B-cell ALL has been less well studied, and there is a need to identify novel therapeutic targets in adult B-ALL. We therefore performed detailed genomic profiling in adults with B-cell ALL. We performed targeted DNA/RNA capture and sequencing of 189 patients with B-cell ALL enrolled on the ECOG E2993 clinical trial. All samples were taken at the time of diagnosis before patients were treated with multi-agent chemotherapy and followed for clinical outcomes including overall survival and remission/relapse duration and kinetics. We used the FoundationOne® Heme assay for our genomics study. This platform allows us to identify short events (point substitutions, short insertions/deletions) copy number and fusion events present in DNA and/or RNA. Of the 203 samples profiled, 189 had sufficient quality genomic data with a median coverage of 435 on DNA sequencing and 7.85 million on target distinct reads per case on RNA sequencing. In all, we identified cancer-related mutations in 108 genes, 55 of these genes being mutated in more than one sample. We identified a median of 2.98 genomic alterations per sample (standard deviation of 1.78) in the target gene set, which included all genes known to be altered in B-ALL and in other hematologic malignancies. The most common genomic events were the BCR-ABL1 fusion (69 samples, 36.5%), followed by CDKN2A loss (57 samples, 30%), CDKN2B loss (35 samples, 18%), NRAS and KRAS point mutations (32 samples, 16.9%), and MLL fusion genes with a spectrum of partners (25 samples, 13.2%). Notably, we found that BCR-ABL1 fusion are mutually exclusive with both RAS mutations (p<10^-7) and MLL mutations (p<5*10^-4). We next investigated the spectrum and frequency of alterations observed in different classes of oncogenes/tumor suppressors. We identified mutations which result in activation of oncogenic signaling pathways in 130 cases or 68.7% of our cohort. This included known mutations/fusions, such as BCR-ABL, RAS-MAPK pathway mutations, and JAK-STAT pathway alterations, and included missense alleles, insertion/deletion events, and fusion genes targeting a spectrum of genes including ABL, PDGFRB, and CRLF2. In aggregate, 33.8% of the cohort had mutations which activate signaling exclusive of BCR-ABL, demonstrating the high prevalence of the Ph-like B-ALL subtype in adult B-ALL. We identified mutations affecting key transcription factors, including PAX5 and IKZF1, in 31.2% of our cohort including missense, nonsense and deletion events. To confirm our ability to detect small deletions of PAX5 and IKZF1, we performed array CGH of 50 cases and compared copy number calls using high-throughput sequencing and CGH. Of note, all deletions targeting PAX5 and IKZF1 identified by NGS were confirmed by CGH. We also identified mutations in epigenetic regulators in 30.6% of cases, including MLL fusions, mutations in the DNA methylation/hydroxymethylation the pathway (DNMT3A, TET1, TET2), and mutations targeted chromatin modulators. Detailed analyses of the mutational spectra and their relationship to clinical outcome will be presented at the meeting. Taken together, these data show we can use a clinically validated sequencing assay to identify known and novel somatic mutations in adult B-ALL, including sequence alterations, rearrangements and copy number aberrations. These data demonstrate the feasibility of combined DNA and RNA study to identify a complex landscape of fusions and short mutations with prognostic and therapeutic relevance, and inform the use of genomic profiling in B-ALL in the clinical context. Figure 1. Figure 1. Disclosures He: Foundation Medicine, Inc.: Employment, Equity Ownership. Brennan:Foundation Medicine, Inc.: Employment, Equity Ownership. Nahas:Foundation Medicine, Inc.: Employment, Equity Ownership. Balassubramanian:Foundation Medicine, Inc.: Employment, Equity Ownership. Otto:Foundation Medicine, Inc.: Employment, Equity Ownership. Lipson:Foundation Medicine, Inc.: Employment, Equity Ownership. Stephens:Foundation Medicine, Inc.: Employment, Equity Ownership. Miller:Foundation Medicine, Inc.: Employment, Equity Ownership. van den Brink:Boehringer Ingelheim: Consultancy, Other: Advisory board attendee; Merck: Honoraria; Regeneron: Honoraria; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees; Tobira Therapeutics: Other: Advisory board attendee. Rowe:Amgen: Consultancy; BioSight Ltd.: Consultancy, Membership on an entity's Board of Directors or advisory committees; BioLineRx Ltd.: Consultancy. Levine:Foundation Medicine: Consultancy; CTI BioPharma: Membership on an entity's Board of Directors or advisory committees; Loxo Oncology: Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 2943 Background: Inhibitor of apoptosis (IAP) proteins represents a conserved group of proteins that are important regulators of cell survival and apoptosis. X-linked IAP (XIAP) is the best studied IAP that inhibits pro-apoptotic caspases 3, 7 and 9. Multiple myeloma (MM) cell lines express high levels of XIAP. The levels of XIAP are further increased when stimulated by cytokines IL6 and IGF-1, both secreted in copious amounts in myeloma microenvironment. The other two main IAP proteins, namely cIAP1 and cIAP2 are not direct inhibitors of caspases. Instead, they modulate the levels of various signaling pathways by ubiquitinating proteins within the pathways. The NFKB pathway could be activated or inhibited by cIAP1 and 2. In MM, deletions of cIAP1 and cIAP2 have been shown to activate non-canonical NFKB pathway, which indicates a possible tumor suppressor role of these proteins. We wanted to investigate the role of the three IAPs by using a small molecule inhibitor. Our studies clearly indicate the importance of inhibiting all the three IAPs for the induction of apoptosis in MM cells. Methods: LCL161 was synthesized by Novartis Inc. (Basel, Switzerland). Stock solutions were made in DMSO, and subsequently diluted in RPMI-1640 medium for use. MM cell lines were cultured in RPMI 1640 containing 10% fetal bovine serum (20% serum for primary patient cells) supplemented with L-Glutamine, penicillin, and streptomycin. Cytotoxicity was measured using the MTT viability assay and proliferation using thymidine uptake. Apoptosis was measured using flow cytometry with Annexin V-FITC and propidium iodide (PI) for cell lines and patient cells. Immunoblotting was done on cell extracts at various time points following incubation with the drug in order to study the cell signaling pathways. siRNA to cIAP2 was purchased from Invitrogen and was electroporated into MM1S cells. Results: We first examined baseline levels of cIAP1, cIAP2 and XIAP in several MM cell lines and a few patient cells. We observed that the IAPs were constitutively expressed in MM cells. We then wanted to examine the functional significance of these IAP proteins in MM cells. For this, we used an IAP inhibitor LCL161. We observed that LCL161 was able to induce cytotoxicity and inhibit proliferation of MM cells, albeit with differences observed between cell lines. We then examined the factors contributing to resistance in the less sensitive cell lines. For this we chose H929, a sensitive cell line and MM1S, a less sensitive cell line to LCL161. Upon treatment with LCL161, cIAP1 and XIAP were down regulated accompanied by increase in levels of activated caspases 9, 8 and 3 in both H929 and MM1S cells. Using LCL161 in combination with a caspase 9 or a caspase 8 or a pan caspase inhibitor showed clearly that the extrinsic pathway is more involved in the LCL161 induced cell death process. LCL161, however, was unable to inhibit cIAP2 in the less sensitive cell line MM1S whereas cIAP2 was not found to be expressed in H929 cells. It has been shown that cIAP1 is required for ubiquitination and degradation of cIAP2. Therefore, cIAP1 down regulation by LCL161 could actually be contributing to the lack of down regulation of cIAP2 and the observed resistance to LCL161. In order to test this, we used a siRNA to cIAP2 and transfected it into MM1S cells by electroporation. We observed that the siRNA reduced cIAP2 levels and in combination with LCL161 led to marked increase in cells undergoing apoptosis. We also examined signaling pathways after treatment with LCL161 and observed upregulation of both canonical and non-canonical NFKB pathways and Jak/Stat pathway in MM1S cells and not in H929 cells. Combining LCL161 with a Jak2 specific inhibitor SD-1029 synergized in inducing cell death in MM1S and other cell lines less sensitive to LCL161. We are currently testing this combination in MM patient cells. Conclusion: These studies demonstrate the importance of inhibiting cIAP1, cIAP2 and XIAP together in MM cells. Furthermore, by this study we were able to identify resistance mechanisms that are upregulated due to inhibiting the IAP proteins and the importance of using agents that inhibit the IAPs along with inhibitors of these pathways in inducing apoptosis in MM cells. The findings from these studies form the basis of evaluation of IAP inhibitors in combination with a Jak/Stat pathway inhibitor in patients with MM. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Merck: Consultancy, Honoraria; Millennium Pharmaceuticals, Inc.: Research Funding; Novartis: Research Funding; Genzyme: Research Funding; Cephalon: Research Funding.

Abstract Background: Multiple myeloma cells are heterogenous in terms of the expression of CD45 and previous studies have suggested important clinical and biological implications of the CD45 expression. It has been shown that expression of CD45 on myeloma cells has prognostic value and that the CD45 positive cells contain the proliferative fraction of the myeloma cells. We have also demonstrated that the CD45+ population has a higher apoptotic rate compared to CD45− cells. Given the hypothesis that CD45+ cells represent myeloma cells earlier in their development and are more proliferative and more dependent on the marrow microenvironment we studied differences between the two populations in patients with different stages of monoclonal gammopathies and in normal plasma cells. Methods: Fresh bone marrow aspirates were subjected to ACK lysis for removal of RBCs subjected to multicolor flow cytometry to study the expression of different surface antigens on the plasma cells. Plasma cells were identified based on their characteristic CD38/45 expression. The surface expression of CD19 (B cell marker), CD56 (NCAM), CD87, (involved in cellular adhesion, cell motility and angiogenesis), CD126 (IL-6 receptor alpha chain), sVEGF (surface VEGF; surrogate measure of VEGF receptor expression), and CD71 (proliferation marker) were studied and compared between the CD45 + and CD45− cells by gating separately on these populations. Results: Patients with active myeloma (76), smoldering myeloma (32), MGUS/amyloid (44), and normal patients (23) were studied. Not all markers were performed on all patients. Among the patient samples, the expression of CD19, CD87, CD71, CD126, and sVEGF were higher among the CD45+ cells compared to CD45− cells (Table: % of cells with expression). There was no significant difference between the two in terms of the expression of CD56. Among the normal plasma cells, the expression of CD19, CD87, CD126 and sVEGF was greater on the CD45+ cells compared to CD45− plasma cells and CD56 was not different. When the patient cells were compared to normal cells, the expression of CD19 was higher among the normal CD45+ plasma cells and CD56, CD87 and CD126 were less. The expression sVEGF was comparable Conclusion: In this study we demonstrate differences between CD45+ and CD45− plasma cells in patients with monoclonal gammopathies. These findings are important for understanding the disease biology and provide an insight into the functional differences seen between these two populations. The increased expression of CD19 in the CD45+ cells supports the notion that these cells are likely to be at an earlier developmental stage. The comparable CD56 expression is not in accordance with previous studies and needs to be examined in a larger group of patients. Increased expression of sVEGF and CD126 as well as the adhesion molecules is in accordance with increased responsiveness and dependence of the CD45+ cells to VEGF and IL-6 and the increased proliferative rates. These findings indirectly support the hypothesis that CD45 negative cells are less dependent on the marrow microenvironment and the cytokine milieu that it provides.

Abstract Abstract 3069 Disease relapse remains a major obstacle to the success of allogeneic hematopoietic stem cell transplantation (HSCT) for patients with hematologic malignancies (HM), and the principal cause of failure after reduced intensity conditioning HSCT. Much work has focused on identifying the risk factors for relapse and devising strategies for its prevention, but comparatively little is known about the outcome of patients who relapse and the relevant prognostic factors in this setting. We conducted a retrospective study of 1080 consecutive adult patients with HM transplanted at our institution between 2004 and 2008. 351 (33%) relapsed at a median of 4.5 months after HSCT. The 4-year post-relapse overall survival (pr-OS) was 15%, with a median post-relapse follow-up of 39 months. Significant risk factors for post-relapse mortality included shorter time to relapse, higher disease risk index1 at HSCT, myeloablative conditioning, and high HCT-CI2 at HSCT. While being on immunosuppression at the time of relapse did not significantly affect outcome in multivariable models, a history of acute or chronic graft-versus host disease (GVHD) prior to relapse conferred a higher risk for death after relapse. Based on those 5 factors and their hazard ratio for mortality in the Cox models, we constructed a simple risk score that stratified patients into 4 groups, with 4-year pr-OS ranging from 64% in patients with fewer than 3 points (13% of the cohort, among whom over one third had myeloid diseases) to 0% in those with greater than 6 points (p<0.0001) (Figure). This score performed similarly in a historical validation cohort of 276 relapsed patients who were transplanted between 1998 and 2003. An analysis of the impact of post-relapse treatment on outcome showed that immune manipulation, through either donor lymphocyte infusion or repeat HSCT, was associated with significantly better pr-OS (4-year pr-OS 28% versus 9%, p<0.0001). Even though this likely reflects in part selection bias, the difference remained significant in models that accounted for other post-relapse prognostic factors, in landmark analyses of patients who survived at least 2 months from relapse, and in patients with active GVHD at the time of relapse. The results of this study may aid with prognostication and management of patients who relapse after HSCT, as well as motivate the design of clinical trials aimed at relapse prevention or treatment in the higher-risk groups. Figure. Post-Relapse Overall Survival by risk score. Figure. Post-Relapse Overall Survival by risk score. Risk factors are: Disease Risk Index (0 points for low risk, 1 point for intermediate, 2 points for high or very high)1Time to relapse (0 points for >24 months, 1 point for 6–24 months, 2 points for 3–6 months, 3 points for <3 months)HCT-CI (0 points for index of 0–2, 1 point for index of 3+)2Myeloablative conditioning (1 point)Prior GVHD (1 point) Disclosures: No relevant conflicts of interest to declare.

Abstract Background: Lenalidomide with dexamethasone (Rd) is a standard of care used for pts with relapsed multiple myeloma (RMM). The randomized, open-label, multicenter, phase 3 study ASPIRE (NCT01080391) is comparing carfilzomib, lenalidomide, and dexamethasone (KRd) to Rd in pts with RMM. The primary end point is progression-free survival (PFS; assessed by an independent review committee). Secondary end points include overall survival (OS), overall response rate (ORR), duration of response (DOR), health-related quality of life (EORTC QLQ-C30 Global Health Status/QoL), and safety. Methods: Adults with RMM who received 1–3 prior regimens were eligible. Pts were randomized (1:1) to receive KRd or Rd and were stratified by β2-microglobulin levels (<2.5 vs ≥2.5 mg/L), prior bortezomib (no vs yes), and prior R (no vs yes). All pts received lenalidomide (25 mg) on days 1–21 and dexamethasone (40 mg) on days 1, 8, 15, and 22 of a 28-day cycle. In addition, KRd pts received K as a 10-min infusion on days 1, 2, 8, 9, 15, and 16 during cycles 1–12 (20 mg/m2 [days 1 and 2 of cycle 1]; 27 mg/m2 thereafter); K was omitted on days 8 and 9 during cycles 13–18 and was not administered beyond 18 cycles. Cycles were repeated until disease progression, unacceptable toxicity, or withdrawal of consent. The study had 90% power to detect a 25% reduction in risk for PFS events for KRd vs Rd (hazard ratio [HR]=0.75) at a 1-sided significance level of 0.025. A stratified log-rank test was used for the PFS comparison. Results: Data are presented for KRd followed by Rd throughout the abstract. Between July 2010 and March 2012, 792 pts from 20 countries were randomized. Baseline characteristics were balanced between the 2 groups. Median age was 64.0 years (range: 31.0‒91.0). Pts received a median of 2 prior regimens in each group. In both the KRd and Rd groups, 66% of pts received prior bortezomib; 20% of pts in each arm received prior R. Median treatment exposure was 22 cycles (KRd) and 14 cycles (Rd). At the time of the prespecified interim analysis, the study met the primary end point for PFS (HR=0.69; 95% confidence interval [CI]: 0.57–0.83; P<.0001), with a longer duration of median PFS in the KRd group (26.3 months [mo]; 95% CI: 23.3–30.5) compared with the Rd group (17.6 mo; 95% CI: 15.0–20.6). Median OS was not reached in either group; however, there was a trend toward longer OS with KRd compared with Rd (HR=0.79; 95% CI: 0.63–0.99; P=.018), which did not meet the prespecified statistical boundary at the interim analysis of survival (P=.005). The Kaplan-Meier OS event-free rates at 24 mo were 73.3% (95% CI: 68.6‒77.5) and 65.0% (95% CI: 59.9‒69.5). The ORR was 87.4% (95% CI: 83.7–90.5) with KRd and 66.9% (95% CI: 62.0–71.5) with Rd. Median DOR was 28.6 mo (95% CI: 24.9–31.3) and 21.2 mo (95% CI: 16.7–25.8). In the KRd and Rd groups, 31.8% vs 9.4% achieved a stringent complete response (sCR) or complete response (CR) (sCR: 14.1% vs 4.3%; CR: 17.7% vs 5.1%), and 70.4% and 40.7% achieved ≥very good partial response. KRd consistently improved Global Health Status/QoL compared with Rd over 18 cycles of treatment (P=.0001). Treatment discontinuation due to an adverse event (AE) occurred in 15.2% (KRd) and 17.4% (Rd) of pts. In each group, 7.7% and 8.5% of pts died while still on study treatment or within 30 days of receiving the last dose of study treatment. The most common hematologic treatment-emergent AEs (TEAEs) (≥grade 3) included neutropenia (29.6% vs 26.5%), anemia (17.9% vs 17.2%), and thrombocytopenia (16.6% vs 12.3%). The most common nonhematologic TEAEs (all grade) included diarrhea (42.3% vs 33.7%), fatigue (32.9% vs 30.6%), and cough (28.8% vs 17.2%). The most common nonhematologic TEAEs (≥grade 3) included pneumonia (12.5% vs 10.5%), hypokalemia (9.4% vs 4.9%), and hypophosphatemia (8.4% vs 4.6%). Other TEAEs of interest (grouped terms; all grade) included dyspnea (22.4% vs 18.0%), hypertension (preferred term; all grade: 14.3% vs 6.9%; grade 3: 4.3% vs 1.8%), acute renal failure (8.4% vs 7.2%), cardiac failure (6.4% vs 4.1%), and ischemic heart disease (5.9% vs 4.6%). Rates of peripheral neuropathy (PN) (grouped terms; all grade) were 17.1% and 17.0%; ≥grade 3 PN was infrequent (2.6% and 3.1%). Conclusion: The addition of carfilzomib to lenalidomide and dexamethasone in pts with RMM resulted in a statistically significant and clinically meaningful improvement in PFS. KRd had an acceptable safety and tolerability profile and represents a potential new standard of care. Disclosures Stewart: Novartis: Consultancy; Array BioPharma: Consultancy; BMS: Consultancy; Millenium: Research Funding; Celgene: Consultancy. Off Label Use: Carfilzomib is approved in the United States for the treatment of patients with multiple myeloma who have received at least two prior therapies including bortezomib and an immunomodulatory agent and have demonstrated disease progression on or within 60 days of completion of the last therapy. ASPIRE is a randomized, multi-center, phase 3 study investigating the use of carfilzomib in combination with lenalidomide and dexamethasone for the treatment of patients with relapsed multiple myeloma who have received 1–3 prior regimens.. Dimopoulos:Celgene: Consultancy, Honoraria; Onyx: Consultancy, Honoraria. Masszi:Janssen Cilag: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Spicka:Janssen-Cilag: Consultancy, Honoraria, Research Funding, Speakers Bureau; Novartis: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau. Oriol:Celgene: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau. Hájek:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees. Rosiñol:Celgene: Honoraria; Janssen: Honoraria. Siegel:Onyx: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Millennium: Honoraria, Speakers Bureau. Niesvizky:Onyx Pharmaceuticals: Consultancy, Research Funding, Speakers Bureau; Millennium: Consultancy, Research Funding, Speakers Bureau; Celgene: Consultancy, Research Funding, Speakers Bureau. Jakubowiak:Onyx Pharmaceticals: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. San Miguel:Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Onyx: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; MSD: Membership on an entity's Board of Directors or advisory committees; Millinnium: Membership on an entity's Board of Directors or advisory committees. Ludwig:Celgene: Research Funding, Speakers Bureau; Takeda Celgene: Research Funding, Speakers Bureau; Bristol-Myers: Research Funding, Speakers Bureau. Zojwalla:Onyx Pharmaceticals, an Amgen subsidiary: Employment, Equity Ownership. Tonda:Onyx Pharmaceticals, an Amgen subsidiary: Employment, Equity Ownership. Xing:Onyx Pharmaceticals, an Amgen subsidiary: Employment, Equity Ownership. Moreau:Novartis: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Onyx: Honoraria, Membership on an entity's Board of Directors or advisory committees. Palumbo:Onyx Pharmaceuticals: Consultancy, Honoraria; Millennium Pharmaceuticals: Consultancy, Honoraria; Janseen-Cilag: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Genmab A/S: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Honoraria; Amgen, Inc,: Consultancy, Honoraria; Array BioPharma: Honoraria.

Abstract Background: Triplet regimens combining a proteasome inhibitor, an immunomodulatory drug, and a steroid have been shown to be active and well tolerated in previously untreated MM pts. Extended treatment represents an alternative paradigm to induction followed by ASCT in this setting; however, agents for continuous therapy need to be convenient and well tolerated. The investigational agent ixazomib is the first oral proteasome inhibitor to be studied clinically. Phase 1 studies have indicated single-agent activity in relapsed/refractory MM and shown ixazomib to be well tolerated with a manageable safety profile, including limited peripheral neuropathy (PN) (Richardson PG et al, Blood 2014; Kumar SK, et al, Blood 2014). Weekly ixazomib plus lenalidomide-dexamethasone has been investigated in a phase 1/2 study in previously untreated MM pts (NCT01217957); treatment comprised triplet induction therapy followed by single-agent ixazomib maintenance therapy. Results of induction therapy have been previously reported (Kumar SK, et al, ASH 2012). Here we report phase 2 efficacy and safety data in pts receiving ixazomib maintenance. Methods: In phase 2, pts aged ≥18 yrs with measurable disease and no grade ≥2 PN received oral ixazomib 4.0 mg on d 1, 8, 15, lenalidomide 25 mg on d 1–21, and dexamethasone 40 mg on d 1, 8, 15, 22, for up to twelve 28-d induction cycles, followed by maintenance ixazomib on d 1, 8, 15 every 28 d until progression at the dose last tolerated during induction. Transplant-eligible pts could discontinue from study for ASCT after 6 cycles. The primary objective was CR+VGPR rate. Responses were assessed by IMWG criteria. Adverse events (AEs) were graded by NCI-CTCAE v4.02. Results: Fifty pts were enrolled in phase 2; 29 discontinued during induction (cycles 1–12), primarily to undergo ASCT (n=14) or due to AEs (n=6) or pt withdrawal (n=4). Twenty-one pts received ixazomib maintenance therapy (cycle ≥13); 13 (62%) were male, and median age was 68 (range 34–77) years. At data cut-off (June 11, 2014), pts had received a median of 27 treatment cycles (range 15–32), including both induction and maintenance, with a median treatment duration of 26.6 mos (range 13.4–29.6). Mean ixazomib relative dose intensity was 95% and 89% in the induction and maintenance phases, respectively. The mean ixazomib dose administered during maintenance was 3.6 mg weekly. At data cut-off, 11 (52%) pts remained on ixazomib maintenance. Among 49 evaluable phase 2 pts, 44 (90%) achieved ≥PR, including 29 (59%) ≥VGPR. All 21 pts who received ixazomib maintenance had responded to induction therapy. Overall best confirmed/unconfirmed responses in the 21 pts included ≥CR in 11 (52%, of which 4 [19%] were stringent CRs [sCR]), ≥near-CR in 13 (62%), and ≥VGPR in 15 (71%), plus 6 (29%) PR. Responses were rapid and improved during treatment. Median time to first response (≥PR) was 0.99 mos (range 0.92–5.78) and to best response was 7.46 mos (range 1.02–24.74); 33% of pts improved their response during maintenance, including 2 VGPR to near-CR, 3 VGPR to CR, 1 VGPR to sCR, and 1 CR to sCR. At data cut-off, median duration of response was 26.5 mos (range 5.6–26.6+). Among 15 pts achieving ≥VGPR, 5 (33%) had progressed; median duration of ≥VGPR was 23.0 mos (range 3.7–26.1+). All pts were alive after follow-up of 24.6–30.3 mos, including a median follow-up from start of maintenance of 16.9 mos (range 12.9–18.9). Ixazomib maintenance was well tolerated; 15 (71%) pts had drug-related AEs, with only 2 (10%) pts with grade 3 drug-related AEs (hypokalemia, thrombocytopenia) and no grade 4 AEs. The most common (>1 pt) grade 1–2 drug-related AEs were diarrhea (n=8, 38%), nausea, pain in extremity (each n=3, 14%), anemia, and headache (each n=2, 10%). No PN was reported. Serious AEs were reported in 3 (14%) pts during maintenance, including grade 3 acute myocardial infarction, grade 3 pneumonia, and grade 3 orthostatic hypotension; all were considered not related to treatment. Only 1 pt required an ixazomib dose reduction due to an AE (neuralgia). Conclusions: These data indicate that single-agent ixazomib maintenance for up to 1.5 yrs was feasible and generally well tolerated, improved responses following ixazomib-lenalidomide-dexamethasone induction, and contributed to durable responses (median >2 yrs) in previously untreated MM pts not undergoing ASCT. The results support the ongoing phase 3 trial of ixazomib in the maintenance setting (NCT02181413). Disclosures Kumar: Celgene: Consultancy, Research Funding; Millennium: The Takeda Oncology Co.: Consultancy, Research Funding; Onyx Pharmaceuticals: Consultancy, Research Funding; Sanofi-Aventis: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Skyline Diagnostics: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Investigational proteasome inhibitor ixazomib in combination with lenalidomide and dexamethasone and as maintenance therapy for patients with previously untreated multiple myeloma.. Niesvizky:Onyx Pharmaceuticals: Consultancy, Honoraria, Research Funding, Speakers Bureau; Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Millennium: The Takeda Oncology Company: Consultancy, Honoraria, Research Funding, Speakers Bureau. Lonial:Millennium: The Takeda Oncology Company: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Onyx Pharmaceuticals: Consultancy, Research Funding. Laubach:Novartis: Research Funding; Onyx Pharmaceuticals: Research Funding. Hamadani:Millennium: The Takeda Oncology Company: Research Funding. Stewart:Takeda Pharmaceuticals International Co.: Research Funding; Sanofi: Consultancy; Array BioPharma: Consultancy; Bristol Myers Squibb: Consultancy; Celgene: Consultancy; Novartis: Consultancy. Hari:Celgene: Consultancy, Honoraria, Research Funding; Onyx: Consultancy, Honoraria, Research Funding; Millennium: The Takeda Oncology Co.: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Honoraria, Research Funding; Sanofi: Research Funding. Vescio:Celgene: Speakers Bureau; Millennium: The Takeda Oncology Co.: Speakers Bureau; Onyx Pharmaceuticals: Speakers Bureau. Kaufman:Millennium: The Takeda Oncology Co.: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Research Funding; Novartis: Consultancy, Honoraria, Research Funding; Onyx: Consultancy, Honoraria, Research Funding; Janssen: Consultancy, Honoraria; Spectrum: Consultancy, Honoraria; Merck: Research Funding. Berg:Takeda Pharmaceuticals International Co.: Employment. Liao:Takeda Pharmaceuticals International Co.: Employment. Hui:Takeda Pharmaceuticals International Co.: Employment. Richardson:Millennium: The Takeda Oncology Co.: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 1848 Background: Aurora kinases play an important role in cell division by controlling chromatid segregation. Aberrant functions of aurora kinases result in genetic instability, a condition often seen in cancers. While Aurora A is important in the alignment of the sister chromatids, Aurora B, a spindle fiber associated kinase, heavily influences the equal division of sister chromatids and along with the Aurora C kinase also assists in a regulated cell division. Inhibition of either of the Aurora family kinases affects chromosomal alignment and segregation during the course of cell division resulting in polyploidy, cell growth arrest and ultimately cell death. VEGF has been implicated in the increased angiogenesis in MM patients. Increase in VEGF levels leads to upregulation in the Ras/Mek/Erk pathway and increased angiogenesis, cell proliferation and decreased apoptosis. Inhibiting this pathway has shown to induce apoptosis in MM cells. We therefore investigated the role of a small molecule inhibitor A-1014907 that inhibits both aurora kinases and VEGF stimulated Ras/Mek/Erk pathway. Methods: A-1014907 was synthesized and provided by Abbott Laboratories Ltd. Stock solutions were made in DMSO, and subsequently diluted in RPMI-1640 medium for use. MM cell lines were cultured in RPMI 1640 containing 10% fetal bovine serum, penicillin, and streptomycin. Cytotoxicity was measured using the MTT viability assay and proliferation using thymidine uptake. Apoptosis was measured using flow cytometry upon cell staining with Annexin V-FITC and propidium iodide (PI) for cell lines and patient cells. Immunoblotting was done on cell extracts at various time points following incubation with the drug in order to study the cell signaling pathways. Results: A-1014907 was able to induce cytotoxicity and inhibit proliferation in all MM cell lines tested with IC50 values between 50–100nM. Similar extents of inhibition of proliferation was also observed when MM cells were co-cultured with bone marrow stromal cells or HUVEC cells or tumor promoting cytokines IL6, IGF and VEGF. The increase in cytotoxicity was due to apoptotic cell death observed in both MM cell lines and patient cells. Cell cycle assays demonstrated that A-1014907 was able to induce cell cycle arrest at the G2/M stage of cell cycle followed by polyploidy indicative of Aurora B inhibition. We also observed an increase over time the proportion of cells in sub G0/G1 stage indicative of cell death. Western blots were performed to understand the mechanism of action of A-1014907. We observed that A-1014907 was able to significantly down regulate Aurora B activity as measured by pHistone H3 (Ser 10) down regulation. This was accompanied by up regulation of p21 and down regulation of CDK4 and cyclin E both indicative of G2/M arrest. We also observed the ability of A-1014907 to inhibit the Ras/Mek/Erk pathway by measuring levels of pErk post treatment with the drug. A-1014907 potently inhibited pErk levels and this down regulation was also observed when MM cells were co-cultured with either VEGF or HUVEC cells. Furthermore, A-1014907 at sub IC50 doses induced synergistic cell death of MM cell lines when combined with sub IC50 doses of dexamethasone Conclusion and current studies: A-1014907 clearly inhibits the Ras/Mek/Erk pathway and aurora B activity and induces apoptosis in MM cell lines and patient cells. We are currently using siRNA to aurora A in combination with A-1014907. We are also examining the mechanism of action of dexamethasone in combination with A-1014907. All this will help to design clinical trials with A-1014907 either alone or in combination with other anti-MM agents in MM patients. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Merck: Consultancy, Honoraria; Millennium Pharmaceuticals, Inc.: Research Funding; Novartis: Research Funding; Genzyme: Research Funding; Cephalon: Research Funding.

Abstract Abstract 1858 Systemic light chain amyloidosis (AL amyloidosis) is a condition where clonal plasma cells produce misfolded insoluble immunoglobulin light chains that deposit in various organs causing progressive organ dysfunction. Chemotherapy and autologous stem cell transplant (ASCT) when eligible is the standard treatment options for patients with AL amyloidosis. There are several studies who report long term outcomes of patient post ASCT. However, there is a paucity of literature describing the outcomes of patients who have received ASCT but have relapsed. We performed a retrospective study to assess the outcomes and treatment regimens employed following relapse after ASCT. Between 1996 and 2009, 410 patients received ASCT at the Mayo Clinic as first line therapy. Of those 410 patients 42 patients died within 3 months of transplant, 64 patients died without documented relapse, 158 patients were alive without documented progression, and 146 patients had documented progression. Those 146 patients are the subject of our study. The median time to hematologic relapse was 2 years (range: 0.2–15.5 years). At relapse, 59 patients were treated with IMiD based therapy, 36 with alkylator based therapy, 24 with bortezomib, 15 with steroids, and 5 with second ASCT. The respective hematologic response rates were 58%, 33%, 50%, 53%, and 60%. The remaining six patients were not evaluable for response for one other following reasons: organ transplants; no further therapy; inevaluable disease. With a median post relapse follow up of 3.6 years, the median overall survival (OS) from the first post ASCT relapse was 4.6 years. The median post transplant follow up was 6.1 years, the median OS for these patients was 7.3 years from the time of transplant. These data provide novel information about outcomes after SCT relapse, which should be useful not only for patients and doctors but also for investigators designing studies for salvage therapies post-transplant. Disclosures: No relevant conflicts of interest to declare.