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Abstract Abstract 3055 Lenalidomide (Revlimid®) and dexamethasone is an effective regimen for relapsed/refractory (rel/ref) multiple myeloma (MM) patients (pts) with an overall response rate of 60% and median time to progression of 13.4 months (Dimopoulos ME, et al. Leukemia 2009; 23: 2147-52). We combined lenalidomide with the alkylating agent combination of cyclophosphamide and prednisone—an older regimen with minimal cumulative myelosuppression and good activity as second or third line therapy (Trieu Y, et al, Mayo Clin Proc 2005; 80: 1582). The CPR regimen consisted of cyclophosphamide (CY) on days 1, 8, and 15, lenalidomide on days 1–21 and prednisone 100 mg q 2 days in a 28-day cycle. ASA 81 mg/day was given as DVT prophylaxis. Three dose levels were evaluated using a 3 × 3 dose escalation design. Thirty-two pts were entered between 11/2007-06/2009; median age was 64 (42-80) yrs, 60% were male, and immunoglobulin isotype was IgG in 19 (62%), IgA in 8 (25%) and light chain in 4 (13%) pts. Median β2-microglobulin level was 257 (92-767) nm/L, albumin 39 (34-48) g/L, creatinine 83 (50-126) μmol/L, platelet count 355 (75-479) × 109/L and ANC 2.5 (1.1-6.1) × 109/L. The median number of prior regimens was 2 (1-5). Prior therapy included: ASCT (single in 91%; double in 19%), thalidomide (28%) and bortezomib (50%). FISH cytogenetics were available in 13 pts; 1 had del 13q but none had t(4;14) or del p53. Table 1 summarizes protocol treatment delivered. Table 1. Dose level N Cyclophosphamide dose (mg/m2) Lenalidomide dose (mg) Prednisone dose (mg) Median # cycles given 1 3 150 15 100 12 (12–34+) 2 3 150 25 100 10 (9–23) 3 26 300 25 100 17 (5–28+) 1–3 (All) 32 150–300 15–25 100 19 (5–34+) Dose limiting toxicity was not observed during cycle 1 at any dose level. Grade 3–4 toxicities during the trial included: thrombocytopenia in 7 (22%) and neutropenia in 9 (29%), managed with dose reduction and/or growth factors; five episodes of febrile neutropenia occurred, all at dose level 3. In cohort 3, other grade 3–4 non-hematologic toxicities included 1 episode each of abdominal pain/bacteremia, hypokalemia, fatigue, sick sinus syndrome, cardiac amyloidosis, perforated diverticulum and 2 episodes of DVT. Two heavily pretreated pts developed 2° MDS, including 1 previously treated for lymphoma, 43 and 190 mos after the diagnosis of MM. The best response using modified EBMT criteria was documented at a median of 7 (1-26) cycles and included the following: dose level 1 (1 CR, 2 PR); dose level 2 (1 VGPR, 2 PR); dose level 3 (4 CR, 14 VGPR, 11 PR, 1 MR and 1 stable disease). At a median F/U of 16 (5-34) months, 13 pts remain on study and 18 have progressed at a median of 10 (2-23) mos; 1 was lost to F/U and 9 have died of progressive MM. The 1-year actuarial OS and PFS rates are 93% (95% CI 76–98%) and 78% (95% CI 60–89%), respectively. We conclude: 1) the combination of full doses of the agents in CPR can be given in a 28 day cycle with an acceptable safety profile; 2) the objective response rate (CR + PR + MR) in all 32 pts to date is 94%; 3) the 1-year OS of 93% and PFS of 78% compare favorably with other 3-drug combinations in rel/ref MM pts; 4) further evaluation of this regimen in newly diagnosed pts would be of interest. Disclosures: Reece: Celgene: Honoraria, Research Funding. Off Label Use: Combination of lenalidomide and cyclophosphamide and prednisone in relapsed and refractory myeloma patients. Chen:Celgene Corporation: Consultancy, Honoraria, Research Funding. Kukreti:Celgene: Honoraria.

Abstract Introduction: In multiple myeloma, randomized trials of maintenance therapy using thalidomide or lenalidomide following autologous transplant (ASCT) demonstrated prolonged progression-free survival (PFS), but overall survival benefit was inconsistent. The MY.10 trial (n=332) demonstrated improved PFS with thalidomide-prednisone maintenance therapy, but quality of life was inferior and overall survival was not improved. As a randomized trial with a no-treatment control arm and biospecimen collection, MY.10 provides a unique opportunity to identify predictors of benefit from therapy that could be used to personalize treatment. Immunomodulatory drug action is mediated in part through binding to cereblon (CRBN) and downregulation of IRF4. Candidate single nucleotide polymorphisms (SNPs) were selected from the CRBN/IRF4 pathway and other genes previously associated with myeloma prognosis, drug response and toxicity from literature review. The aim of this study was to investigate associations between candidate SNPs and benefit from immunomodulatory compound-based maintenance therapy, as well as prognostic impact. Methods: Genomic DNA was extracted from samples preserved in Trizol¨. SNPs were genotyped using TaqMan¨ genotyping assays on the ViiA7 qPCR platform. Analysis was performed on 187 patients with available samples and clinical data (86 in treatment arm; 101 in observation arm). Cox regression models were performed using SAS clinical 2.0 for prognostic impact of a single SNP on PFS, assessed with and without adjusted covariates (age, stage, performance status and response to ASCT). In treatment benefit analysis, PFS was modeled with genotype, treatment assignment and their interaction term. Results: SNPs with significant prognostic impact for PFS in all 187 patients were found in CRBN (rs1672753) (HR 0.59, 95%CI 0.4-0.86; p=0.006) and the following SNPs which had been found to be prognostic in prior studies were validated: CYP1A1 (rs1048943) (HR 1.98, 95%CI 1.19-3.27; p=0.008), CYP1B1 (rs1056836) (HR 0.72, 95%CI 0.52-0.99; p=0.043), and trend toward significance for SNP in CYP1A2 (rs2069514) (HR 2.02, 95%CI 0.98-4.15; p=0.057). Of these, only the CYP1A1 SNP was found to be possibly predictive of greater benefit from maintenance therapy. A SNP in ABCA1 (rs363717), previously associated with thalidomide-induced neuropathy,‎ was prognostic in this study (HR 1.44, 95%CI 1.03-2.02; p=0.033) but not predictive of treatment benefit. Table 1 lists SNPs associated with a differential level of benefit from maintenance therapy, including SNPs in FAM179a and ICAM1 that were possibly associated with harm from maintenance therapy. Table 1. SNPs and treatment interaction with significant impact on PFS. HR represent hazard ratio of treatment versus observation for a given genotype group. Asterisk Indicates trend toward significance. Wildtype Heterozygote & mutant p-value interaction Gene dbSNP ID SNP HR 95% CI HR 95% CI FAM179A rs1053667 T>C 0.46 0.33, 0.66 2.28 0.78, 6.65 0.003 ICAM1 rs1799969 G>A 0.51 0.36, 0.73 1.75 0.83, 3.70 0.007 CASP3 rs1049216 A>G 0.82 0.54, 1.25 0.41 0.25, 0.69 0.029 IRF4 rs12203592 C>T 0.69 0.47, 1.02 0.38 0.21, 0.69 0.062* CYP1A1 rs1048943 A>G 0.62 0.44, 0.87 0.11 0.02, 0.52 0.079* Conclusion: Previously identified SNPs in drug metabolism and drug efflux genes were validated to be prognostic in this cohort. The prognostic but not predictive significance of a SNP in CRBN suggests a possible role for CRBN in multiple myeloma disease biology independent of immunomodulatory therapy. SNPs predictive of differing degrees of benefit from immunomodulatory maintenance were found in genes involved in immunomodulatory activation, drug action and cell adhesion mediated drug resistance; SNPs in FAM179A and ICAM1 were possibly associated with harm from thalidomide maintenance and could potentially be used to identify patients unsuitable for immunomodulatory maintenance therapy. These results may be applicable to lenalidomide and pomalidomide, since immunomodulatory compounds exhibit similar chemical structures and mechanisms of action. Validation of these SNPs in prospective clinical trials involving other immunomodulatory can test this hypothesis. Further studies are needed to confirm our findings. Disclosures Off Label Use: thalidomide and prednisone maintenance for multiple myeloma. Bahlis:Celgene: Consultancy, Honoraria, Research Funding, Speakers Bureau; Amgen: Consultancy; Johnson & Johnson: Speakers Bureau; Johnson & Johnson: Consultancy; Johnson & Johnson: Research Funding. Song:Celgene Canada: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. White:Celgene Canada: Honoraria, Research Funding. Chen:Celgene: Consultancy, Honoraria, Research Funding. Seftel:Celgene: Honoraria, Research Funding. Howsen-Jan:Celgene: Honoraria, Research Funding. Reece:Amgen: Honoraria; Bristol-Myers Squibb: Research Funding; Merck: Research Funding; Novartis: Honoraria, Research Funding; Onyx: Consultancy; Millennium Takeda: Research Funding; Lundbeck: Honoraria; Otsuka: Research Funding; Janssen-Cilag: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding. Shepherd:Celgene: Honoraria, Research Funding. Chen:Celgene: Honoraria, Research Funding. Djurfeldt:Celgene: Research Funding. Reiman:Soricimed Biopharma Inc: Consultancy, Other: Scientific Advisory Board for Soricimed.

Abstract Abstract 1874 Poster Board I-899 Lenalidomide (Revlimid®) and dexamethasone is an effective regimen in relapsed/refractory multiple myeloma (MM) patients (pts), with an overall response rate of 60.6% and median time to progression (TTP) of 13.4 months (Dimopoulos MA, et al, Leukemia 2009 Jul 23 [Epub ahead of print]). Oral cyclophosphamide and prednisone is an older regimen with excellent patient tolerance, and we sought to enhance the efficacy of lenalidomide by adding oral cyclophosphamide and prednisone in this phase I-II trial. The CPR regimen consisted of cyclophosphamide on days 1, 8 and 15; lenalidomide on days 1–21; and prednisone 100 mg every other day in a 28 day cycle. ASA 81 mg/day was given to all pts as DVT prophylaxis. Three dose levels were evaluated using a 3 by 3 dose escalation design. Between 11/2007–07/2009, 31 pts with relapsed/refractory MM who had not previously received lenalidomide were entered onto study. Median age was 61 (40–78) years and 61% were male. Immunoglobulin subtype was IgG in 19 pts (61%), IgA in 8 pts (26%) and light chain only in 4 pts (13%). Median number of prior regimens was 2 (1–5) and 28 pts had undergone previous ASCT, including double transplants in 6 pts. Prior therapy included thalidomide in 9 (29%) and bortezomib in 15 (48%). FISH cytogenetics were available in 13 pts; one had 13q deletion but none had t(4;14) or p53 deletion. At the time of protocol entry, median β 2-microglobulin level was 246 (92–767) nm/L, albumin 39 (34–48) g/L, creatinine 83 (50–126) μmol/L, platelet count 230 (75–337) × 109/L and ANC 2.5 (1.1–6.1) x 109/L. Protocol treatment is summarized in Table 1. Dose limiting toxicity was not observed during cycle 1 at any dose level. Grade 3–4 toxicities included thrombocytopenia in 5 pts (16%) and neutropenia in 9 pts (29%). These were managed with dose reduction and/or growth factor support. Four episodes of febrile neutropenia occurred. Other grade 3–4 non-hematologic toxicities included abdominal pain/bacteremia in 1 pt in cohort 1; hypokalemia in 1 pt in cohort 2; and DVT in 2 pts, dizziness in 2 pts and fatigue in 1 pt in cohort 3. Using the International uniform response criteria (Durie BG, et al, Leukemia 2006; 20:1467–1473), the best response was documented at a median of 6 (1–5) cycles and included the following: dose level 1 (1 CR, 2 PR); dose level 2 (1 VGPR, 2 PR); dose level 3 (5 CR, 9 VGPR, 9 PR, 1 MR and 1 stable disease). At a median follow-up (F/U) of 12 (8–21) months, 20 pts remain on study, 2 have withdrawn and 9 pts have progressed at a median of 9 (4–13) months; only 1 one has died (due to MM). We conclude: 1) the combination of full doses of the agents in CPR can be given in a 28 day cycle with minimal toxicity; 2) the overall response rate (CR + VGPR + PR) in 31 pts to date is 93%; 3) at a median F/U of 1 year, only 9 pts (29%) have progressed; 4) longer follow-up is required to assess the TTP and survival of the CPR regimen. Disclosures: Reece: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding, Speakers Bureau. Off Label Use: Lenalidomide in combination with drugs other than dexamethasone. Anglin:Celgene: Honoraria. Chen:Celgene: Honoraria, Research Funding. Kukreti:Celgene: Honoraria. Mikhael:Celgene: Honoraria. Trudel:Celgene: Honoraria.

Abstract Abstract 2403 Immunoglobulin light chain amyloidosis (AL) is a monoclonal plasma cell disorder characterized by the accumulation of monoclonal light chain fragments that have undergone a conformational transformation and deposit as amyloid fibrils in different tissues. High-dose melphalan (HDM) with autologous hematopoietic stem-cell transplant (ASCT) is increasingly used to treat patients (pts) with AL Amyloidosis. However, transplant-related mortality (TRM) is high, ranging between 13% to 43%. The survival benefit of HDM has been attributed to a patient-selection bias. Recently, a randomized clinical trial by Jaccard A et al, showed longer survival in the group assigned to receive melphalan plus dexamethasone (Mel/Dex) than in the group assigned to receive HDM. The present is a retrospective study aiming to define which pts with AL are most likely to benefit from HDM. Patients and Methods We retrospectively reviewed the medical records of all the pts included in the Princess Margaret Hospital Amyloidosis Database who underwent ASCT from January 2004 to March 2010 to determine: a) TRM, b) Hematological response (HR) and Organ response (OR) and c) Overall survival (OS). We included transplanted pts who had received no more than two previous courses of any chemotherapy regimen who did not have concurrent myeloma, and who had an Eastern Cooperative Oncology Group (ECOG) performance-status score of 2 or better. As part of the ASCT the stem cells were obtained from the peripheral blood with granulocyte colony-stimulating factor (G-CSF) alone (5 μ g/kg subcutaneously, twice daily). Pts then received HDM, 200 mg/m2 given intravenously on day 0, and stem cells were infused on day 1. The HDM was reduced to 140 mg/m2 for pts 65 years of age or older and for those with an important decrease of the ejection fraction, a calculated creatinine clearance of less than 30 ml per minute, or severe liver disease. HR and OR was assessed using 2004 Amyloidosis Consensus Response Criteria (Gertz, M et al, 2004). For statistical evaluation, HR was defined as observing complete or partial remission (CR or PR); stable disease (SD) or progression was considered as no HR. All statistical tests were 2-sided X2 t test and P values less than .05 were considered to be statistically significant. Results Seventy seven pts were evaluated with a median age of 56 years (33-74). Clinical characteristics are seen in Table 1. Only 18/77 pts (23%) received induction therapy: Dexamethasone alone n=9, Cyclophosphamide and Prednisone n=2, Mel/Dex n=4, VAD n=2 and Melphalan and Prednisone n=1. TRM observed was 12% mainly due to congestive heart failure and sepsis. Complete HR was achieved in 38 cases (49%) and OR was seen in 59%. Among the most common complications to ASCT, febrile neutropenia was reported in 67%, transient renal impairment in 10% and congestive heart failure in 3%. Median OS was significantly lower for patients with B-type natriuretic peptide (BNP) >300 pg/ml (17.7 vs 64.46 months) (p0.0004), Troponin I >0.07 ng/ml (19.25 vs 97.4 months) (p0.00001) and those who achieved a complete HR (115 vs 88 months) (p0.0345). Multivariate Cox regression analysis showed that BNP>300 pg/ml and Troponin I >0.07 ng/ml (normal <0.07) were the most important factors to predict OS for patients with AL who underwent ASCT (p0.0002 and 0.04 respectively). Conclusions Based on this study of 77 patients, clinical selection is the most important factor to better improve outcomes for HDM in AL. Patients with BNP>300 pg/ml and/or abnormal levels of Troponin I (>0.07) should not be considered eligible for transplants due to a high degree of mortality. Our series showed a CR rate of 49% which is higher than 33% reported by Palladini et al with Mel/Dex. Stringent case selection may be the most important factor in decreasing mortality rate associated to ASCT leading to better outcomes. Table 1. Clinical Characteristics of patients with AL Amyloidosis undergoing ASCT (at initial diagnosis) Clinical Characteristics N Median Range % Age (years) 77 57 33–74 Hemoglobin (g/L) 77 138 104–182 Creatinine (μ mol/L) 77 129 37–700 **BNP (pg/ml) 44 180 10–1670 ***BMPC (%)– 77 7 1–30 24 Hr Proteinuria (g/d) 77 5.5 0–24.9 Intraventricular Septal Distance (mm) 77 13 9–23 Kappa/lambda ratio 53 4.4 0.001–71.2 Kidney Involvement 71 Heart Involvement 52 Liver involvement 23 GI involvement 10 3 or more organs involved by AL 16 ** B-Type Natriuretic Peptide *** BMPC: Bone marrow plasma cells Disclosures: Stewart: Millennium: Consultancy; Celgene: Honoraria. Reece: Celgene: Honoraria, Research Funding. Chen: Celgene Corporation: Consultancy, Honoraria, Research Funding. Kukreti: Celgene: Honoraria.

Abstract Abstract 2876 Poster Board II-852 Multiple myeloma (MM) patients (pts) are immunosuppressed given the underlying disease, previous treatments and myelosuppression seen on lenalidomide (Revlimid, Rev). We evaluated the infectious complications seen on Celgene's Expanded Access Rev program at Princess Margaret Hospital. We have treated 75 pts who had progressed after at least one prior therapy as part of a national study in Canada. At entry, pts were required to have a neutrophil count of ≥1.0 ×109/L. The median age was 61 yrs (range 35-79); 52% were males. Prior therapy included stem cell transplant in 65, thalidomide in 54 and bortezomib in 24. Number of lines of prior therapy were as follows: 24 (one), 29 (two), 16 (three), 8 (four) and one (five). Neupogen was used liberally (63%) after a patient had a dose delay on trial due to neutropenia. Patients were treated with full dose lenalidomide at entry onto clinical trial and were maintained on full dosing unless platelet counts were <30×109/L or ANC was <1.0×109/L. No other dose adjustments were made for renal dysfunction. Results: There were 32 pts (43%) who had a clinically evident infection; the majority (91%) was on prophylactic antibiotics (septra/ciprofloxacin) at the time. There were two deaths due to infection and 23 pts (72%) required hospitalization (range 2-27 days). The majority of infections occurred within the first 4 cycles of treatment (26 pts) and seemed to occur more in pts with several lines of prior therapy – 7/24 (29%) with 1 prior therapy, 14/29 (48%) with 2, 9/16 (56%) with 3 and 2/8 (25%) with 4 prior therapies. Sixteen were neutropenic of which 7 had febrile neutropenia (9%). The types of infections were: respiratory in 14 (1 with pneumocystis pneumonia), cellulitis in 4, herpes simplex and herpes zoster in 2 pts each. These included streptococcus pneumoniae (1), staphylococcus aureus (3), respiratory syncitial virus (1) and mycobacterium chelonae (1). Rev was held during the infection in 23 pts (72%). Conclusions: 1) Infections are frequent in this patient population (43%) and often lead to hospitalization (72%); respiratory infections accounted for a large majority (43%). 2) Early aggressive growth factor support and broader antibiotic prophylaxis may be of benefit especially in heavily pretreated patients. 3) Dose reduction of Rev in the context of serious infections should be further evaluated. Disclosures: Kukreti: Celgene: Honoraria. Trudel:Celgene: Honoraria, Speakers Bureau; Ortho Biotech: Honoraria. Chen:Celgene: Honoraria.

Abstract Abstract 1217 Poster Board I-239 Background Single autologous stem cell transplant (ASCT) is considered the standard of care after induction therapy for younger multiple myeloma (MM) patients (pts). However, it is not curative and virtually all patients will ultimately relapse. As more options are available to treat relapsed disease, the role of a second ASCT as salvage therapy is unclear. Method Retrospective review of all MM pts who received a 2nd ASCT as salvage therapy at Princess Margaret Hospital. Results Between February 1997 and July 2009, 79 MM pts received a second ASCT for relapsed MM at our institution. Median age was 60 yrs (range 39-72) at second transplant. 48 pts (61%) were male. Immunoglobulin subtype included IgG (42), IgA (21), light chain (11), nonsecretory (3), IgM(1) and IgD (1). Transplant conditioning regimen for first transplant was high dose melphalan (MEL) 140-200 mg/m2 in 67, busulphan and cyclophosphamide in 1, and combinations of MEL with etoposide (E) or TBI in the rest. 2nd ASCT conditioning consisted of MEL alone in 76, the remaining 3 had MEL with either TBI or E. The median time to relapse after the first transplant was 2.72 years (0.81-8.26), with a median interval between transplants of 3.61 years (1.63-9.59). Response to first transplant in 78 evaluable patients was 13 CR/nCR (17%), 56 PR/VGPR (72%), 9 MR/SD (12%). Nineteen pts received maintenance therapy between transplants. Two transplant-related deaths occurred following 2nd ASCT. In 73 evaluable patients, response to second transplant was 11 CR/nCR (15%), 57 PR (78%), 6 MR/SD (8%). After 2nd ASCT, with median follow up 5.92 years (71 months), median progression-free survival (PFS) was 18.5 months and median overall survival (OS) was 4.4 years. Long term progression-free status based on the progression-free interval after 1st ASCT is summarized Table 1. PFS based on progression free interval after 1st ASCT is outlined in Figure 1. Conclusions 2nd ASCT is a feasible and safe salvage therapy in relapsed MM patients. It is effective in providing a median progression free survival of 18.5 months and median overall survival of 4.4 years (52.8 months) after 2nd ASCT. This is comparable if not better than modern salvage chemotherapies. The longer the disease free interval after 1st ASCT the more effective 2nd ASCT is at extending both progression free survival and overall survival. It is reasonable, therefore, to consider a 2nd ASCT if the time to progression is greater than 2 years after first ASCT. Disclosures Chen: Celgene: Honoraria, Research Funding; Ortho Biotech: Honoraria. Trudel:Celgene: Honoraria, Speakers Bureau; Ortho Biotech: Honoraria. Kukreti:Celgene: Honoraria.

Abstract Background: Lenalidomide (Revlimid®) in combination with dexamethasone was approved in the US on June 29, 2006 for the treatment of subjects with multiple myeloma who had received at least one prior therapy. On February 28, 2005 based upon a positive interim analysis of two pivotal placebo-controlled Phase III studies, an independent Data Safety Monitoring Board recommended the studies be unblinded and all subjects in both studies be given access to lenalidomide. In April 2005, the FDA in association with myeloma patient advocacy groups requested Celgene establish an expanded access program to make lenalidomide plus dexamethasone available to subjects with relapsed or refractory multiple myeloma while the treatment was awaiting approval. Aim: To provide lenalidomide to multiple myeloma subjects with a high likelihood of benefit and to obtain additional safety data. Methods: Subjects with relapsed or refractory multiple myeloma that received at least 1 prior therapy were eligible. Subjects received 25 mg lenalidomide plus high-dose dexamethasone in 4-week cycles until disease progression was documented, study drug was discontinued, or lenalidomide became commercially available for this indication. Results: Between September 8, 2005 and July 25, 2006, approximately 1400 subjects in the US and Canada were enrolled into the study. A data snapshot taken March 17, 2006 demonstrated that 746 subjects had been enrolled, median age was 63 years, 60% were male, and 66.5% had Stage III disease. Median time on study was 7.1 weeks (0.1–24.4) and median daily dose was 20.5 mg. At least one Grade 3 or 4 adverse event was reported in 261 (35%) of the 746 subjects. Most commonly reported Grade 3–4 events were neutropenia (7.9% of subjects), thrombocytopenia (6.0%), fatigue (3.6%), anemia (3.5%), pneumonia (3.1%) and hyperglycemia (2.0%). These most commonly reported Grade 3–4 adverse events were the same as those found in the previous pivotal studies, however, their frequencies of occurrence were lower in the current study probably due to ongoing data collection and differences in study maturity. Likewise, the most commonly reported adverse events (all grades) were the same as those reported in the two previous pivotal studies. Conclusion: Preliminary data from this expanded access program in over 1400 subjects with multiple myeloma are consistent with results from two earlier Phase III pivotal studies. The EAP of lenalidomide plus dexamethasone in multiple myeloma represents a model of how government, advocacy groups, healthcare providers and industry can work together to quickly provide treatment to subjects in need while a clearly active treatment regimen is awaiting approval.

Abstract Abstract 1793 Thalidomide (THAL) and IMID® immunomodulary drugs lenalidomide (LEN) and (POM) have proven beneficial in the treatment of a variety of hematological malignancies. Pre-clinical studies demonstrate multiple direct and indirect anti-tumor activities including anti-angiogeneic, proapoptotic, anti-proliferative and immunomodulatory effects. Recent studies have identified cerebron (CRBN) as a potential direct physical target of THAL and IMiD compounds and CRBN expression is reportedly required for IMiD compound activity. However, the precise link between CRBN and IMiD compound mechanism of action (MOA) have not been clearly defined. We applied Drosophila as a drug discovery platform to assess the MOA of THAL and IMiD compounds in vivo. THAL or POM fed Drosophila demonstrate morphological phenotypes that replicate wingless (wg) mutants indicating that drugs are inhibitors of Wg/Wnt signaling. In this model system, THAL and IMiD compounds disrupt membrane localization of GSK-3 indicating that the bioactivity of IMiD compounds is achieved through spatial regulation and potentiation of Sgg/GSK-3 in Drosophila. Using epistasis analysis we show that Drosophila expressing genetic mutants lacking GSK-3 activity and myeloma cells in which GSK-3a and GSK-3b have been knocked down by siRNA fail to respond to POM. In both Drosophila and myeloma cells therefore it appears that GSK-3 activity is required for biological responses. To test the clinical validity of GSK-3 as a biomarker, we obtained patient tumor samples from a Phase II clinical trial of single agent LEN for previously untreated CLL (Chen CI et al., J Clin Oncol, 2011; 29:1175). Twenty five patients were enrolled onto this study and received LEN at a starting dose of 2.5 mg days 1–21 of a 28 day cycle with monthly escalation to a target dose of 10 mg. The primary clinical endpoint for the trial was objective response to lenalidomide (complete response (CR) and partial response (PR)) evaluated as defined in the revised 1996 NCI Working Group guidelines. Peripheral blood samples for correlative studies were collected on days 1 (pre-dosing) and 8 of cycles 1 and 2. CRBN expression was evaluated by gene expression profiling and Western blot and found to be uniformly expressed in all 19 evaluable day 1 patient samples regardless of LEN response. Thus CRBN expression does not appear to be a useful predictive biomarker of response in this population of previously untreated patients. However, GSK-3 localization was correlated with response. Paired analysis of CD19 selected CLL cells comparing day 1 vs day 8 revealed focal membrane localization of GSK-3 on day 1 and subcellular redistribution on day 8 in 11 out of 12 evaluable responders (PR or better). By contrast, in the CLL cells from all 6 evaluable non-responders, GSK-3 expression appeared diffusely distributed before and after treatment. In preliminary studies using confocal immunofluorescence microscopy we determined that CRBN and GSK-3 co-localize in day 1 CLL samples of responders but not in those of non-responders. In summary, our results indicate that THAL and the IMiD compounds target GSK-3 function by spatial regulation and identify GSK-3 localization as a potential clinical biomarker of IMiD response. Disclosures: Trudel: Celgene: Honoraria; GlaxoSmithKline: Research Funding; Janssen: Honoraria. Mercurio:Celgene: Equity Ownership, Research Funding. Lopez-Girona:Celgene Corp: Employment, Equity Ownership. Gaidarova:Celgene Corp: Employment, Equity Ownership. Webb:Celgene: Employment, Equity Ownership. Chen:Johnson & Johnson: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; GlaxoSmithKline: Research Funding; Lundbeck: Consultancy. Stewart:Millenium: Consultancy, Honoraria, Research Funding; Onyx: Consultancy; Celgene: Consultancy. Manoukian:Celgene: Research Funding.

Abstract Background: In the pivotal FIRST trial, at the pre-specified planned analysis for progression-free survival (PFS), treatment (Tx) with lenalidomide plus low-dose dexamethasone until disease progression (Rd continuous) improved outcomes for transplant-ineligible patients (pts) with newly diagnosed multiple myeloma (NDMM) compared with melphalan, prednisone, and thalidomide (MPT), as well as Rd for 18 cycles (Rd18; Benboubker, NEJM 2014). Rd18 was added as a third arm to investigate whether Rd continuous Tx would control progression of NDMM longer than Rd18. Here, we present the final analysis of the overall survival (OS) data from the trial. Methods: Transplant-ineligible pts with NDMM were randomized 1:1:1 to Rd continuous (with lenalidomide given on days 1-21 of 28-day cycles until disease progression), Rd18 (with lenalidomide given on days 1-21 of eighteen 28-day cycles), or MPT (twelve 42-day cycles); both Rd18 and MPT were 72 weeks in duration. The primary endpoint was PFS and the key secondary endpoint was OS; the primary comparison was Rd continuous vs MPT. Other secondary endpoints included time to second therapy (TTST) and safety. Time from randomization to second progression or death (PFS2) was an exploratory analysis. Response assessment used for PFS and PFS2 analysis was determined by investigators based on International Myeloma Working Group criteria. Results: At the time of cutoff for the final OS analysis (January 21, 2016), 52 of the 535 pts in the Rd continuous arm and none of the pts in the Rd18 (n = 541) and MPT (n = 547) arms continued to receive Tx. The median follow-up for surviving pts was 67.0 months (range, 0-86.8 months). In the pre-specified final OS analysis for the primary comparison, a statistically significant advantage in OS was shown with Rd continuous over MPT (hazard ratio [HR], 0.78; 95% confidence interval [CI], 0.67-0.92; P = .00234; Table). OS for Rd continuous vs Rd18 was evaluated (HR, 1.02; 95% CI, 0.86-1.20). In this updated analysis, a PFS advantage continued to be seen for Rd continuous vs MPT (HR, 0.69; 95% CI, 0.59-0.79; P < .00001) and vs Rd18 (HR, 0.70; 95% CI, 0.60-0.81). Median TTST was longer for Rd continuous vs MPT (HR, 0.63; 95% CI, 0.54-0.73; Table). More pts in the Rd18 and MPT arms started second-line therapy (n = 377 and 381, respectively) compared with the Rd continuous arm (n = 299). Pts received a variety of Tx at progression, with bortezomib-based regimens the most common in the Rd continuous (n = 179; 59.9%), Rd18 (n = 208; 55.2%), and MPT (n = 170; 44.6%) arms. Pts who received bortezomib after Rd continuous or Rd18 had better outcomes than those who received it after MPT. PFS2 for Rd continuous was improved vs MPT (HR, 0.74; 95% CI, 0.64-0.85). Grade 3/4 adverse events (AEs) occurred in 86.3%, 80.2%, and 88.7% of the 532, 540, and 541 pts in the safety populations of the Rd continuous, Rd18, and MPT arms, respectively; the most common grade 3/4 AEs were neutropenia (29.5%, 26.5%, and 44.9%) and infections (31.6%, 21.9%, and 17.2%), and no new safety signals were seen compared with earlier analyses. Study discontinuation was most commonly due to disease progression and was less common in the Rd continuous vs Rd18 and MPT arms (50.7% vs 66.9% and 61.6%, respectively). Discontinuation due to AEs was similar across the Rd continuous, Rd18, and MPT arms (12.0%, 13.1%, and 13.9%). Solid tumor second primary malignancies (SPMs) occurred in 6.0, 6.9%, and 5.9% of pts, and hematologic malignancies occurred in 0.8%, 0.4%, and 2.6% of pts in the Rd continuous, Rd18, and MPT arms, respectively. Conclusions: Rd continuous significantly prolonged PFS and OS, and improved other secondary endpoints compared with MPT in transplant-ineligible pts with NDMM. Rd continuous also showed a PFS benefit compared with Rd18, delaying the time to next Tx. PFS2 outcomes suggest that Rd does not induce resistant relapses. Few hematologic malignancies occurred in the Rd arms, and the incidence of SPMs was similar between Rd continuous and Rd18. Rd continuous remains a standard of care for transplant-ineligible pts with NDMM. Disclosures Facon: Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Other: travel and expense, Speakers Bureau. Dimopoulos:Genesis: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees. Dispenzieri:Celgene: Research Funding. Belch:Takeda: Honoraria; Janssen: Honoraria; Amgen: Honoraria; Celgene: Honoraria. Cavo:Bristol-Myers Squibb: Consultancy, Honoraria; Janssen-Cilag: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria; Millennium: Consultancy, Honoraria. Weisel:BMS: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Janssen: Consultancy, Honoraria, Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Onyx: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Novartis: Consultancy, Research Funding. Ludwig:Janssen: Speakers Bureau; BMS: Speakers Bureau; Takeda: Research Funding, Speakers Bureau; Amgen: Research Funding, Speakers Bureau. Bahlis:BMS: Honoraria; Amgen: Consultancy, Honoraria; Celgene: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Janssen: Consultancy, Honoraria, Other: Travel Expenses, Research Funding, Speakers Bureau; Onyx: Consultancy, Honoraria. Delforge:Janssen: Honoraria; Celgene: Honoraria; Amgen: Honoraria. Cavenagh:Amgen: Consultancy, Speakers Bureau; Novartis: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Celgene: Consultancy, Speakers Bureau. Geraldes:Celgene: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; BMS: Consultancy, Honoraria; Janssen: Consultancy, Honoraria. Oriol:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: 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. De La Rubia:Amgen, Bristol, Celgene, Janssen: Consultancy, Speakers Bureau. White:Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding. Moreau:Celgene: Honoraria; Amgen: Honoraria; Takeda: Honoraria; Novartis: Honoraria; Janssen: Honoraria, Speakers Bureau; Bristol-Myers Squibb: Honoraria. Attal:janssen: Consultancy, Research Funding; amgen: Consultancy, Research Funding; celgene: Consultancy, Research Funding; sanofi: Consultancy. Ervin-Haynes:Celgene: Employment, Equity Ownership. Chen:Celgene: Employment, Equity Ownership. Houck:Celgene: Employment. Hulin:celgene: Honoraria; Bristol: Honoraria; Janssen: Honoraria; Amgen: Honoraria; takeda: Honoraria. Benboubker:Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Takeda: 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.

Abstract Abstract 718 Introduction: In a previously reported phase 2 study of single agent lenalidomide in 25 untreated CLL patients (pts), we reported an overall response rate (ORR) of 56% (14 pts), 40% SD (10 pts) and no CR at a median follow-up of 20.7 months (Chen et al. JCO 2010;29:1175). Although an amended protocol with conservative lenalidomide dosing was used to mitigate tumor lysis and severe myelosuppression observed in the first 2 accrued pts, we continued to observe frequent toxicities of grade 3–4 neutropenia (72%) and tumor flare (TF 88%). We now report long-term efficacy and toxicity from this study at a median follow-up of 47 months (mos). Methods: Patients were eligible if previously untreated and symptomatic (cytopenias, symptomatic adenopathy/organomegaly, constitutional symptoms, lymphocyte doubling count <12 mos). The amended starting dose for lenalidomide was 2.5mg daily on days 1–21 of a 28 day cycle, with slow monthly dose escalations (2.5mg cycle 1, 5mg cycle 2, 10mg cycle 3 and if required for response, further 5mg increments to a maximum of 25mg daily were allowed). Results: Longterm toxicities: Hematologic toxicities were common: grade 3–4 neutropenia (76%), thrombocytopenia (28%), anemia (20%). With longer term use, neutropenia tended to recur (12% of all cycles) and 10 pts required GCSF support (5 routinely during each cycle). Most common non-hematologic toxicities (all grades) were TF (88%), fatigue (76%), rash (60%), muscle cramping (40%), diarrhea (40%). All non-hematologic toxicities were mild (grade 1–2), except for 1 pt each with grade 3 rash and diarrhea. Although TF was most common during cycle 1, repeat flare symptoms upon resuming lenalidomide after the 7 day rest period of each cycle were noted in 16% of all 898 cycles administered, and as late as at cycle 28. Infections were mild (most respiratory, skin) with only 2 grade 3 events (disseminated zoster, S.pneumoniae bacteremia). Other malignancies: 2 pts developed transformed large cell lymphoma 7 and 18 mos after study discontinuation, 1 pt developed squamous cell carcinoma of skin at cycle 51, and 1 pt developed recurrence of remote non-small cell lung cancer at cycle 34. Dose modifications/discontinuation: The median highest dose achieved for all 25 pts was 15 mg (range 2.5–25 mgs); 8 pts were able to escalate to the maximal 25mg dose. Ten pts (40%) required dose reductions for grade 3 cytopenias [neutropenia (2), thrombocytopenia (2), both (2)], febrile neutropenia (2), and diarrhea (2). Of all 25 pts, the median duration on therapy was 31.1 mos (range 28 days – 60.6 mos). Twelve pts (52%) currently remain on study, receiving a median of 59 cycles of therapy (range 48–66). Causes of discontinuation for 13 pts included: treatment-related toxicity (8), lack of response/progressive disease (4), and recurrence of remote lung cancer (1). Toxicities leading to discontinuation included: prolonged cytopenias (3), recurrent infections (1), atrial fibrillation (1), disseminated herpes zoster (1), persistent grade 2 diarrhea (1), and grade 3 skin rash (1). Efficacy: With extended median follow-up from 20.7 to 47 mos, the ORR improved from 56% (14 pts) to 72% (18 pts), with 3 pts in PR upgrading to CR, and 1 SD to PR. Although the median time to response was 7.7 mos, responses occurred as quickly as 1.8 mos to as late as 27.0 mos of therapy. For the 3 CR pts, prolonged therapy with an additional 14.9, 28.3 and 40.6 mos beyond the time of first response was required to achieve CR. To date, 7 pts have progressed with 3-year PFS 68.8% (95% CI:52–91%) and OS 85.3% (95% CI:71.1–100%). Correlatives: Cereblon (CRBN), recently identified as a direct protein target of lenalidomide, was evaluated by gene expression profiling and Western blot and found to be uniformly expressed in all 19 evaluable day 1 pt samples regardless of lenalidomide response. Thus, baseline CRBN expression does not appear to be a useful predictive biomarker of response in this population. The mechanism by which CRBN is linked to response is reported by Trudel et al, ASH 2012. Conclusions: Long-term followup of this study demonstrates that when using low doses of single agent lenalidomide in CLL, prolonged therapy is feasible and may be required for the achievement of durable, high quality responses. Maximal daily doses of 25mg can be reached and may also be needed for optimal response, though recurrent myelosuppression remains limiting. Disclosures: Chen: Celgene: Honoraria, Research Funding; GlaxoSmithKline: Research Funding; Lundbeck: Consultancy; Janssen: Consultancy, Research Funding. Off Label Use: Lenalidomide is not approved for use in chronic lymphocytic leukemia. Kukreti:Roche: Honoraria; Celgene: Honoraria; Janssen Ortho: Honoraria. Trudel:Celgene: Honoraria, Research Funding, Speakers Bureau.