ALBERT

Description: Multiple myeloma (MM), a malignancy of plasma cells, is characterized by widespread genomic heterogeneity and, consequently, differences in disease progression and drug response. Although recent large-scale sequencing studies have greatly improved our understanding of MM genomes, our knowledge about genomic structural variation in MM is attenuated due to the limitations of commonly used sequencing approaches. In this study, we present the application of optical mapping, a single-molecule, whole-genome analysis system, to discover new structural variants in a primary MM genome. Through our analysis, we have identified and characterized widespread structural variation in this tumor genome. Additionally, we describe our efforts toward comprehensive characterization of genome structure and variation by integrating our findings from optical mapping with those from DNA sequencing-based genomic analysis. Finally, by studying this MM genome at two time points during tumor progression, we have demonstrated an increase in mutational burden with tumor progression at all length scales of variation.

Description: Introduction: Selinexor is a novel, first-in-class selective inhibitor of nuclear export (SINE), which blocks XPO1, forcing the nuclear retention and activation of tumor suppressor proteins. Selinexor in combination with low dose dexamethasone (Sel-dex) was recently approved based on data from the STORM study, wherein Sel-dex induced an overall response rate (ORR) of 26.2% in patients with penta-exposed, triple-class refractory multiple myeloma (MM). The recommended phase 2 dose (RP2D) of twice-weekly combination of selinexor, carfilzomib, and dexamethasone (SKd) was selinexor 60 mg, carfilzomib 20/27 mg/m2 and dexamethasone 20 mg (NCT02199665). The ORR of this regimen in patients with MM refractory to carfilzomib in last line of therapy (n=13) was 62% and clinical benefit response was 77% (Jakubowiak et al. Br J Haematol 2019). This is consistent with data from the combination of selinexor, bortezomib and dexamethasone where a 43% ORR was observed in bortezomib refractory disease. We conducted the STOMP study to assess the safety and preliminary efficacy of SKd combination using once weekly (QW) dosing in patients with relapsed/refractory MM. Methods: STOMP is a multicenter, open-label study. Patients with relapsed/refractory MM that was not refractory to carfilzomib, and who may have had prior proteasome inhibitor exposure were enrolled. Oral Selinexor was dosed QW at 80 or 100 mg. Carfilzomib was dosed QW (excluding day 22 of 28-day cycle) at 56 mg/m2 or 70 mg/m2. Dexamethasone was dosed at 40 mg QW. The primary objectives of the study are to assess the maximum tolerated dose, RP2D and evaluate the efficacy and safety of SKd in patients with relapsed/refractory MM. Results: As of July 01 2019, 12 patients were enrolled in the study. Of these, 5 were male and 7 were female. The median age was 70 years (range: 50-76 years). The median number of prior treatments was 4 (range: 2 - 8). Nine of 12 patients received prior autologous stem cell transplantation. All 12 patients were carfilzomib naïve. Nine of 12 patients had MM refractory to bortezomib; 11 patients had MM refractory to lenalidomide and/or pomalidomide including 5 patients with MM refractory to both; and 7 patients with MM refractory to daratumumab. Four dose limiting toxicities (DLTs) were observed across 3 dose cohorts (Table 1). Common treatment related adverse events (Grade 1/2 , Grade ≥3) included anemia (42%, 17%), thrombocytopenia (17%, 58%), leukopenia (17%, 17%), nausea (67%, 0%), decreased appetite (33%, 0%), insomnia (33%, 0%), hyperglycemia (25%, 17%), fatigue (25%, 8%), vomiting (25%, 8%), and pneumonia (0%, 17%). The ORR was 75% including 3 complete responses, 5 very good partial responses and 1 partial response. Two patients had stable disease and 1 patient had minimal response. As of July 01, 8 patients remain on treatment. Conclusions: The once weekly SKd combination demonstrated encouraging preliminary activity with an ORR of 75% including complete responses and very good partial responses. Most DLTs were thrombocytopenia and all the DLT events occurred in patients with baseline Grade 1/2 thrombocytopenia. This activity and manageable side effect profile with QW selinexor in combination with carfilzomib and dexamethasone is promising. Disclosures Gasparetto: Celgene: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; BMS: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed ; Janssen: Consultancy, Honoraria, Other: Travel, accommodations, or other expenses paid or reimbursed . Schiller:Gilead: Research Funding; Incyte: Research Funding; J&J: Research Funding; Jazz Pharmaceuticals: Honoraria, Research Funding; Karyopharm: Research Funding; Novartis: Research Funding; Onconova: Research Funding; Pfizer Pharmaceuticals: Equity Ownership, Research Funding; Sangamo Therapeutics: Research Funding; Daiichi Sankyo: Research Funding; Eli Lilly and Company: Research Funding; FujiFilm: Research Funding; Genzyme: Research Funding; Agios: Research Funding, Speakers Bureau; Amgen: Other, Research Funding; Constellation Pharmaceutical: Research Funding; Astellas: Research Funding; Biomed Valley Discoveries: Research Funding; Bristol Myer Squibb: Research Funding; Celgene: Research Funding, Speakers Bureau. Lentzsch:Caelum Biosciences: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; Bayer: Consultancy; Janssen: Consultancy; Takeda: Consultancy; BMS: Consultancy; Proclara: Consultancy; Abbvie: Consultancy; Clinical Care Options: Speakers Bureau; Sanofi: Consultancy, Research Funding; Multiple Myeloma Research Foundation: Honoraria; International Myeloma Foundation: Honoraria; Karyopharm: Research Funding; Columbia University: Patents & Royalties: 11-1F4mAb as anti-amyloid strategy. Tuchman:Roche: Research Funding; Alnylam: Honoraria, Research Funding; Karyopharm: Honoraria; Prothena: Research Funding; Celgene: Honoraria, Research Funding, Speakers Bureau; Amgen: Research Funding; Sanofi: Research Funding; Merck: Research Funding. Bahlis:Takeda: Consultancy, Honoraria; AbbVie: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. White:Amgen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria. Chen:Amgen: Honoraria; Celgene: Honoraria, Research Funding; Janssen: Honoraria, Research Funding. Baljevic:Cardinal Health Specialty Solutions: Consultancy; Takeda Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Other: Internal Review Committee participant. Kotb:Takeda: Honoraria; Amgen: Honoraria; Merck: Honoraria, Research Funding; Celgene: Honoraria; Janssen: Honoraria; Karyopharm: Equity Ownership. Leblanc:Amgen: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Sebag:Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Venner:Celgene: Honoraria; Janssen: Honoraria; Amgen: Honoraria, Research Funding; J&J: Research Funding; Sanofi: Honoraria; Takeda: Honoraria. Bensinger:Amgen, Celgene: Other: Personal Fees, Research Funding, Speakers Bureau; Takeda, Janssen: Speakers Bureau; Sanofi, Seattle Genetics, Merck, Karyopharm: Other: Grant. Sheehan:Karyopharm Therapeutics: Employment, Equity Ownership. Chai:Karyopharm Therapeutics: Employment, Equity Ownership. Kai:Karyopharm Therapeutics: Employment, Equity Ownership. Shah:Karyopharm Therapeutics: Employment, Equity Ownership. Shacham:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Kauffman:Karyopharm Therapeutics Inc: Employment, Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Lipe:Celgene: Consultancy; amgen: Consultancy; amgen: Research Funding.

Description: Autologous PBSCT remains an integral part of therapy for MM patients (pts) but the sequencing and repeat applications of this intervention vary among transplant centers. Current NCCN guidelines (V 2.2014) and expert panels (e.g. IMWG Consensus Statement, Leukemia10: 1904) recommend collecting sufficient PBSCs for 2 transplants and indefinite storage. As MM survival continues to improve, the period between initial treatment and first or salvage PBSCT may span years. Many centers face issues of overflowing freezers, unreimbursed storage costs and referring providers opting for salvage treatment options other than PBSCT. Outside providers may also be unaware or forget that previously collected PBSCs are available for transplant or doubt the usefulness of the treatment. We therefore analyzed the fate of PBSCs collected for MM pts from 2005-2013 at our center. METHODS: All MM pts who underwent any attempt at PBSCT collection between 2005 and 2013 (n=304) were included. UW Stem Cell lab provided storage records, medical records were reviewed to establish current clinical status, treating physicians and patients were also contacted. RESULTS: 304 MM pts had PBSCs collected between 2005-2013. This accounted for 479 apheresis procedures, median 2/pt., range 1-4, with a median of 2 aliquots per procedure stored totaling 930 aliquots (median 2/pt.; range 1-10). Ultimately, 267 underwent PBSCT. Of those pts, 98 (32%) used all collected cells. Leftover cells remained for 206 pts (68%) during this 9 year time span. Of those, 37 pts (18% of those with leftover cells) have never undergone transplant (Table 1) Table 1. Outcome of patients who have never used stored PBSCs (n=37) OUTCOME Number Percentage (n=37) Have not progressed from initial therapy 19 51% Pt refused transplant 6 14% Never offered ; died of MM 14% Collection Inadequate 2 5% Cells sent to other transplant site 2 5% Transplant pending 3 8% Not offered due to PD 1 3% PD= progressive disease; The remaining 169 pts had a least one PBSCT and had leftover aliquots (82%) (Table 2) Table 2. Outcome of patients receiving one PBSCT with remaining cells OUTCOME Number Percentage Have not progressed from PBSCT 88 52% Died of PD; 2nd PBSCT never offered 23 14% Relapsed, alive, 2nd PBSCT not offered 17 10% Relapsed

Description: Abstract 621 Background: Two- and three-drug regimens incorporating bortezomib (Velcade®, V), lenalidomide (Revlimid®, R), dexamethasone (D), or cyclophosphamide (C) have been shown to be effective and well tolerated in previously untreated multiple myeloma (MM). Combining all four drugs in a single regimen (VDCR) may further enhance efficacy. Published results from the phase 1 dose-escalation portion of the non-comparative, multi-center EVOLUTION study showed that the VDCR regimen was highly active and generally well tolerated (Kumar et al Leukemia 2010). Here we present updated results from the phase 2 portion of the trial, focusing on efficacy and safety of the VDCR, VDR, and VDC regimens. Methods: Previously untreated patients with measurable disease were randomized to one of four treatment groups receiving up to eight 21-d cycles of VDCR (V 1.3 mg/m2 d 1, 4, 8, 11; D 40 mg d 1, 8, 15; R 15 mg d 1–14; C 500 mg/m2 d 1, 8), VDR (VD as in VDCR but with R 25 mg d 1–14), VDC (VDC as in VDCR), or VDC-mod (as for VDC but with an additional dose of C on d 15) as induction therapy, followed by four 42-d maintenance cycles of V 1.3 mg/m2 (d 1, 8, 15, 22) (all treatment arms). Patients eligible for autologous stem cell transplant (SCT) could undergo stem cell mobilization any time after cycle 2 and SCT any time after cycle 4. The primary endpoint was the combined complete response (CR) + very good partial response (VGPR) rate; secondary endpoints included safety/tolerability, time to response, duration of response, progression-free survival, and rate of minimal residual disease (MRD) negativity. Responses were assessed according to International Myeloma Working Group (IMWG) uniform criteria using an automated computer algorithm. Adverse events (AEs) were graded using the CTCAE v3.0. Results: Patient characteristics were similar among the groups with respect to age, performance status, ISS stage, and proportion of patients with high-risk cytogenetic features. Patients received a median of 5, 6, 6, and 6 treatment cycles in the VDCR, VDR, VDC, and VDC-mod arms, respectively; 65%, 60%, 52%, and 47% of patients had dose reductions of any drug. In the VDCR, VDR, VDC, and VDC-mod arms, respectively, 52%, 62%, 58%, and 65% of patients completed treatment; 31%, 43%, 24%, and 41%, respectively, underwent SCT. In the phase 2 response-evaluable patients (n=132), all treatment regimens showed substantial efficacy, with CR+VGPR rates of 59% (VDCR), 50% (VDR), 41% (VDC), and 59% (VDC-mod) (Table) (includes pre-transplant responses only in SCT patients). Of MRD-assessed patients, 46% (21/46) of those who achieved CR (including sCR) or nCR were MRD-negative; 48% (10/21), 75% (9/12), 0% (0/7) and 33% (2/6) in the VDCR, VDR, VDC and VDC-mod arms, respectively. Median time to first response was similar across arms (range 1.6–1.8 months); median time to best response of CR+VGPR was 4.0 months (VDCR), 3.4 months (VDR), 5.1 months (VDC), and 3.1 months (VDC-mod). Median duration of response has not been reached in any arm to date. All treatment regimens were generally well tolerated. In the VDCR, VDR, VDC, and VDC-mod arms, at least one grade ≥3 AE was observed in 81%, 76%, 79%, and 88% of enrolled patients, respectively; serious AEs were experienced by 42%, 40%, 21%, and 41% of patients, and AEs resulting in study discontinuation were reported for 19%, 17%, 12%, and 6% of patients. The five most common all-grade AEs across all treatment groups were fatigue (range 47–67%), nausea (36–67%), constipation (40–62%), diarrhea NOS (42–65%), and neutropenia (19–52%). The incidence of grade ≥3 (grade ≥2) peripheral neuropathy (PN) was 13% (40%) in the VDCR arm, 14% (45%) VDR, 9% (48%) VDC, and 18% (41%) VDC-mod; there was no grade 4 PN. Rates of grade ≥3 neutropenia/thrombocytopenia were 42%/10% for VDCR, 7%/7% VDR, 36%/12% VDC, and 65%/18% VDC-mod. Conclusions: All regimens appear highly active and generally well tolerated in previously untreated MM patients. The four-drug combination did not result in a substantial increase in response rate and was associated with a modest increase in the incidence of hematologic toxicities. Continuous weekly C in the VDC regimen was associated with high response rates and rapid responses, comparable to the VDR and VDCR arms. Outcome data will be presented following longer follow-up. Disclosures: Kumar: Celgene: Consultancy, Research Funding; Millennium: Consultancy, Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding; Bayer: Research Funding. Off Label Use: Lenalidomide for treatment of newly diagnosed myeloma. Flinn:Millennium Pharmaceuticals, Inc.: Research Funding. Richardson:Celgene, Millennium, Novartis, Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees. Hari:Celgene: Research Funding. Callander:Millennium Pharmaceuticals, Inc.: Research Funding. Noga:Amgen: Honoraria, Research Funding, Speakers Bureau; Millennium: Consultancy, Honoraria, Research Funding, Speakers Bureau; Ortho-Centicor: Honoraria, Speakers Bureau; Cephalon: Honoraria, Research Funding, Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau. Stewart:Millennium Pharmaceuticals, Inc.: Honoraria, Research Funding; Celgene: Honoraria. Rifkin:Millennium Pharmaceuticals, Inc.: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Speakers Bureau; Amgen: Speakers Bureau; Cephalon: Speakers Bureau; Dendreon: Speakers Bureau. Wolf:Millennium Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Genentech and Multiple Myeloma Research: Membership on an entity's Board of Directors or advisory committees; Novartis: Honoraria, Speakers Bureau; OrthoBiotech: Honoraria, Speakers Bureau; Celgene: Honoraria, Speakers Bureau. Estevam:Millennium Pharmaceuticals: Employment. Mulligan:Millennium Pharmaceuticals, Inc.: Employment. Shi:Millennium Pharmaceuticals: Employment. Webb:Millennium Pharmaceuticals: Employment.

Description: Aim: A phase III trial of lenalidomide plus high (standard) dose dex (RD) versus lenalidomide plus low dose dex (Rd) in newly diagnosed myeloma (MM). Methods: Pts with untreated, symptomatic MM were eligible. Pts in the RD arm (Arm A) received lenalidomide 25 mg/day PO days 1–21 every 28 days plus dex 40 mg days 1–4, 9–12, and 17–20 PO every 28 days; pts in the Rd arm (Arm B) received lenalidomide at the same dose plus dex 40 mg days 1, 8, 15, and 22 PO every 28 days. The primary endpoint was response rate at 4 months, with the null hypothesis being that the response rates in the two 2 arms are equivalent. Planned sample size was 196 eligible pts per arm with one-sided 0.10 Type I and 0.05 Type II error rate. All analysis were performed on an intent to treat basis. An independent DMC recommended release of study results. Results: 445 pts (median age, 65 yrs) were accrued; 223 randomized to RD, 222 to Rd. Median follow-up time is 17 months. Arms were well balanced for age, gender, stage, bone lesions, hemoglobin, beta-2 microglobulin, performance status, bone marrow plasma cells, and M protein levels at baseline. Major grade 3 or higher toxicities, including DVT/PE and infections, were significantly higher in the high dose dex arm (see Table). Overall survival (OS) at the second pre-planned interim analysis was significantly superior with lenalidomide plus low dose dex, P

Description: Abstract 38 INTRODUCTION: Lenalidomide and bortezomib have moved into the management of newly diagnosed multiple myeloma leading to dramatically improved outcomes. As a consequence, the role of upfront autologous peripheral blood stem cell transplant (ASCT) has become more controversial. The ECOG E4A03 clinical trial randomized newly diagnosed MM patients to lenalidomide with high-dose dexamethasone (LD) vs lenalidomide with low-dose dexamethasone (Ld) (Rajkumar et al Lancet Oncol 2010; 11: 29–37). Upon completing four cycles of therapy, pts had the option of ASCT or continuing on the assigned therapy. The purpose of this abstract is to determine the outcome of patients on this trial pursuing early ASCT according to various age-groups. MATERIALS and METHODS: This is a post hoc, retrospective analysis of overall survival within age subgroups stratified by early ASCT status. This is a landmark analysis including only pts surviving the first 4 cycles of therapy. RESULTS: In all three age-groups studied, 1, 2, and 3-year survival probability estimates with ASCT were excellent (Tables 1, 2, and 3). For patients under the age of 65 who survived the first 4 cycles of therapy, overall survival at 3-years was 94% with early ASCT, 78% in pts continuing protocol therapy. Although direct comparison with patients not going to early transplant is not possible because the assignment to early ASCT versus no early ASCT was not randomized, survival with ASCT at 3-years appeared higher. While we attempt to correct for age, the differences may be influenced by other factors such as performance status, comorbidities, response to therapy, etc. The presumption that treatment related mortality (TRM) should be more problematic for older pts undergoing ASCT is addressed by looking at the 〉65 and 〉70yo cohorts. In the 〉65 age group, one-year mortality is similar between the early ASCT population and the no early ASCT population. In the 〉70 age group, no adverse impact of early ASCT was seen in the first year on overall survival but the sample size is extremely small. In all age groups early ASCT seemed to mitigate some of the survival disadvantage associated with randomization to the LD arm. CONCLUSIONS: This analysis shows that the strategy of lenalidomide plus dexamethasone induction followed by early ASCT has a remarkably good outcome in terms of overall survival in all age groups studied and supports the continued role of early consolidative ASCT in newly diagnosed patients. The risk of early mortality was notably low in the first year in all age groups. The risk of early mortality seems to increase at 2 years for the LD pts not choosing early ASCT and at 3 years for the Ld pts not choosing early ASCT. Selection bias makes it difficult to compare results for pts that chose early ASCT directly to the patients who did not receive early ASCT in this trial. As such, these results emphasize the need for randomized trials investigating the timing of ASCT in myeloma in the era of novel therapy. Disclosures: Siegel: Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Millennium Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Merck: Membership on an entity's Board of Directors or advisory committees. Off Label Use: Lenalidomide for front line therapy. Abonour:Celgene: Speakers Bureau; Millennium Pharmaceuticals: Speakers Bureau. Callander:Millennium Pharmaceuticals: Research Funding. Fonseca:Amgen: Consultancy; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy, Research Funding; Genzyme: Consultancy; Onyx: Research Funding; Otsuka: Consultancy; Medtronic: Consultancy. Vesole:Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau.

Description: The interaction between malignant plasma cells and non malignant bone marrow microenvironment has been recognized as both an important feature of MM propagation and a therapeutic target. One critical interaction appears to involve angiogenesis as evidenced by increased blood vessel density in areas of myeloma cell proliferation. The potent anti MM compound lenalidomide may work partly through down regulation of VEGF expression by bone marrow stromal cells. We hypothesized that the addition of the VEGF-A receptor inhibitor, bevacizumab, in combination with low dose weekly dexamethasone, would provide more complete blockade of VEGF activation and translate to increased activity in MM patients with relapsed or refractory disease. ELIGIBILTY: relapsed or refractory MM patients (pts), failing 〉1 therapy, with no previous exposure to lenalidomide, measurable M protein in serum and/or urine, no current history of unstable cardiovascular disease or uncontrolled thrombosis, no therapy for ≥28 days, and no contraindication to aspirin. METHODS: Each 4 week cycle consisted of lenalidomide 25 mg PO d1–21, bevacizumab 10 mg/kg IV over 2 hours every two weeks, and dexamethasone 40 mg PO q week. All pts received aspirin 325 mg PO daily. Prior to therapy pts underwent bone marrow biopsy and aspirate. MM and stromal cells were isolated for analysis of STAT 3 activation to assess the treatment’s effect on stromal/MM cell interactions. Clinical responses were assessed using IBMTR criteria. RESULTS: 17 pts have been enrolled, ages 53––89, with median number of previous regimens 3 (range 1–6). Two pts were taken off study during the first cycle, one due to GI perforation occurring d 6 of therapy, and one pt due to rapidly progressive disease during first week of therapy. Ten pts have completed ≥ 4 cycles and can be evaluated for response. Seven of 10 pts achieved a PR after a median of two cycles and have maintained that response. One pt progressed after completing one cycle, one pt progressed after 5 cycles, and one pt had stable disease after 6 cycles. Expected grade 3 toxicities included DVT in 2 patients (both of whom were on aspirin but received erythropoiesis stimulating agents) and 2 pts developed shortness of breath attributed to bevacizumab, with resolved after discontinuation of the drug; one patient developed atrial fibrillation which spontaneously converted. No patient developed hypertension or proteinuria. Most required a dose reduction of lenalidomide due to fatigue. Analysis of STAT3 DNA-binding in MM cells alone or in co-culture with MM-BMSCs revealed variable low levels of constitutive STAT3 activity and enhanced activity in co-culture. No additional effect of bevacizumab + revlimid on constitutive STAT3 activity was observed. CONCLUSIONS: the combination of lenalidomide, bevacizumab and low dose dexamethasone has activity in relapsed and refractory myeloma. The initial 70% response rate compares favorably with the 58% response rate reported by Stadtmauer et al (Blood 108:3552) in previously treated MM pts receiving lenalidomide and high dose dexamethasone. Toxicities of this regimen are predictable but manageable. The use of ESAs may contribute to the development of DVT and the protocol has been modified to preclude their use.

Description: Abstract 3885 Poster Board III-821 The interaction between malignant plasma cells and non malignant bone marrow microenvironment has been recognized as both an important feature of MM propagation and a therapeutic target. One critical pathway appears to involve neoangiogenesis as evidenced by increased blood vessel density in areas of myeloma cell proliferation. The potent anti MM compound lenalidomide may work partly through down regulation of VEGF expression by bone marrow stromal cells. We hypothesized that the addition of the VEGF-A receptor inhibitor, bevacizumab, in combination with low dose weekly dexamethasone, would provide more complete blockade of VEGF activation and boost the response rate in MM patients with relapsed or refractory disease over lenalidomide and dexamethasone alone. ELIGIBILTY Relapsed or refractory MM patients (pts), failing 〉1 prior therapy, and no previous exposure to lenalidomide, measurable M protein in serum and/or urine, no current history of unstable cardiovascular disease or uncontrolled thrombosis, no therapy for 28 days, and no contraindication to aspirin. METHODS Pts received 4 week cycles consisted of lenalidomide 25 mg PO d1–21, bevacizumab 10 mg/kg IV over 2 hours every 2 weeks, and dexamethasone (D) 40 mg PO q week. All pts received aspirin 325 mg PO daily. Prior to therapy pts underwent bone marrow biopsy and aspirate. MM and stromal cells were isolated for analysis of STAT 3 activation to assess treatment effect on stromal/MM cell interactions. Plasma VEGF, VEGFR-1 and MIP-1α levels were measured at baseline and after 2 cycles. Clinical responses were assessed using IBMTR criteria every 2 cycles. Pts continued on treatment until progression or toxicity. This study was designed as a Simon minimax two-stage design with 19 pts, followed by 14 additional pts with 10 or more responders out of the initial 19 to detect an objective response rate of 70% with power 0.9 from 45% at a significance level of 0.05. RESULTS As of this reporting, 31 pts have been enrolled, ages 41–89, with median number of previous regimens 3 (range 1–7), previous transplant 27%. Three pts are considered unevaluable as they were taken off study before 2 cycles, two due to GI perforation and one pt due to rapidly progressive disease during first week of therapy. One pt is too early for evaluation. Twenty-seven pts have completed 〉4 cycles and have been evaluated for response. Responses are as follows: Complete response-15% (n=4), Partial response 56% (n=15), stable disease 19% (n=5), and progressive disease 11% (n=3). Overall response rate of 70% (a 95% confidence interval 50%–86%) is not significantly different from that reported by Weber et al (NEJM 357:2133) of 61% (a 95% CI 53%–68%) in patients receiving lenalidomide and high dose D. However, overall grade 3/4 toxicities were significantly less than those reported by Weber. Grade 3/4 toxicities included DVT in 3 patients (all were on aspirin but received erythropoiesis stimulating agents), and 2 pts developed shortness of breath attributed to B, which resolved after discontinuation of the drug; 3 pts developed atrial fibrillation. No patient developed hypertension or proteinuria. Most required a dose reduction of lenalidomide due to fatigue. Analysis of STAT3 DNA-binding in MM cells alone or in co-culture with MM-BMSCs revealed variable levels of constitutive STAT3 activity and enhanced activity in co-culture. No additional effect of bevacizumab + lenalidomide on constitutive STAT3 activity was observed. Patients with no constitutive STAT3 activity were those achieving CR. CR was also associated with low plasma MIP-1α and VEGF levels. CONCLUSIONS The combination of B added to lenalidomide and low dose D has activity in relapsed and refractory myeloma. The initial 70% response rate is not statistically superior to the 60% response rate reported by Weber et al in previously treated MM pts receiving lenalidomide and high dose D. Toxicities of this regimen are predictable from the expected side effect profile of each drug but manageable. The use of ESAs may contribute to the development of DVT, and the protocol was modified to preclude their use. Low levels of constitutive STAT-3 activation and plasma MIP-1α predict for response in this trial. Acknowledgments Supported by the U Wisc Carbone Cancer Center (P30 CA14520), Wisconsin Oncology Network, and NCI Translational Research Initiative 25×5097. Genentech Lab and Celgene Corp provided B and lenalidomide for correlative studies. Disclosures: Callander: Millenium: Research Funding. Off Label Use: bevacizumab for multiple myeloma.

Description: NRAS Q61 mutations are prevalent in advanced/relapsed multiple myeloma (MM) and correlate with poor patient outcomes. Thus, we generated a novel MM model by conditionally activating expression of endogenous NrasQ61R and a MYC transgene in germinal center B cells (VQ mice). VQ mice developed a highly malignant MM characterized by high proliferation index, hyperactivation of ERK and AKT signaling, impaired hematopoiesis, widespread extramedullary disease, bone lesions, kidney abnormalities, preserved PD1 and TIGIT immune checkpoint pathways, and expression of human high-risk MM gene signatures. VQ MM mice recapitulate most of the biological and clinical features of human advanced/high-risk MM. These MM phenotypes are serially transplantable in syngeneic recipients. Two MM cell lines were also derived to facilitate future genetic manipulations. Combination therapies based on MEK inhibition significantly prolonged the survival of VQ mice with advanced stage MM. Our study provides a strong rationale to develop MEK inhibition-based therapies for treating advanced/relapsed MM.

Description: Introduction: There is no standard treatment for Mantle cell lymphoma (MCL). Intensive treatment strategies such as conventional R-hyperCVAD with alternating R-cytarabine/methotrexate or autologous stem cell transplant appear to improve PFS but the effect on OS is unclear. In addition, approximately 50% of newly diagnosed patients are not candidates for intensive therapies. Novel treatment strategies are needed. We have published the results of a study using a modified R-hyperCVAD induction followed by maintenance rituximab (Kahl et al, Ann Oncol 2006). This induction strategy yielded a complete response (CR) rate of 64% and the entire treatment program yielded a median PFS of 37 months. Bortezomib (Velcade) has demonstrated promising activity in relapsed MCL (Fisher et al, J Clin Onc, 2006). We hypothesized that the incorporation of Velcade (Vc) into the induction regimen would improve the CR rate. The new regimen, VcRCVAD, was tested for safety and efficacy in a phase II study at the University of Wisconsin and within the Wisconsin Oncology Network. Methods: Eligible patients had histologically confirmed mantle cell lymphoma, PS 0–2, and adequate end organ function. The final treatment plan included: Velcade 1.3 mg/m2 days 1 and 4, rituximab 375 mg/m2 IV day 1, cyclophosphamide 300 mg/m2 IV over 3 hrs q 12 hrs X 6 doses days 1–3, doxorubicin 50 mg/m2 continuous infusion over 48 hrs days 1–2, vincristine 1 mg IV day 3, dexamethasone 40 mg po days 1–4. Due to excessive painful peripheral neuropathy (PN), 2 dose modifications were required during the course of the study. Patients 1–7 received 1.5 mg/m2 Velcade and 2 mg vincristine. Patients 8–14 received 1.3 mg/m2 Velcade and 2 mg vincristine. Patients 15–30 received 1.3 mg/m2 Velcade and 1 mg vincristine. Cycles were repeated every 21 days for 6 cycles and all patients received G-CSF cytokine support. Patients achieving at least a PR receive maintenance rituximab therapy for 5 years. Results: Enrollment is complete and all 30 patients are evaluable for response to VcRCVAD induction. Baseline characteristics include median age 60.5 (48–74), 24M:6F, 26/30 (87%) stage IV, and 12 (40%) low-risk, 8 (27%) int-risk, and 10 (33%) high-risk by MIPI. 3 patients (10%) experienced PD during induction therapy and 27 (90%) responded with 23 CR/CRu (77%) and 4 PR (13%). With a median follow up of approximately 18 months, the 18-month PFS and OS are 73% and 97%, respectively. The major toxicity of this treatment regimen is painful PN and expected hematologic toxicity. 5/7 patients in cohort 1 and 3/7 patients in cohort 2 developed grade 3 painful PN and 1 patient in cohort 2 developed grade 4 painful PN. Only 1/16 patients in the final cohort experienced grade 3 painful PN. All neuropathy eventually improved to ≤ grade 2, but 10 patients require chronic medication for symptom relief. 13/167 (8%) of the treatment cycles were complicated by neutropenic fever/infection. There were no treatment related deaths. Conclusion: The VcR-CVAD induction has produced high overall response (90%) and CR rate (77%) in a very representative MCL patient population. Comparing these data to our previous frontline MCL study, the CR rate appears to be enhanced (77% vs 64%) by the addition of Velcade. Longer follow up is needed before determining if the higher CR rate will translate into an improved PFS and OS. Because of the risk for painful PN, caution must be exercised when using vincristine and Velcade in combination. The MTD for this combination was 1 mg vincristine and 1.3 mg/m2 Velcade. The encouraging complete response rate provided the rationale for ECOG study E1405, which is testing the safety and efficacy of this induction regimen in a cooperative group setting.