Kyle, Robert A.

Abstract Background: Increasingly thalidomide (Thal) plus dexamethasone (Dex) is being used as initial therapy for multiple myeloma (MM), but there is a need to minimize non-hematologic toxicity with this regimen. CC-5013 (lenalidomide; Revlimid™) is a more potent analog of thalidomide with significantly fewer non-hematologic toxicities that has shown promising results in relapsed refractory myeloma. We report the initial results of the first phase II trial using the combination of CC-5013 plus Dex (Rev/Dex) as initial therapy for newly diagnosed MM. Methods: The trial is designed to accrue 31 eligible patients; 13 patients (pts) (11 male and 2 female) were analyzed in this interim report. Patients were enrolled between February 2004 and July 2004. CC-5013 was given orally at a dose of 25 mg daily on days 1–21 of a 28-day cycle. Dex was given orally at a dose of 40 mg daily on days 1–4, 9–12, 17–20 of each cycle. Patients also received an aspirin once daily as thrombosis prophylaxis. Response was defined as a decrease in serum monoclonal (M) protein by 50% or higher and a decrease in urine M protein by at least 90% or to a level less than 200 mg/24 hours. Responses were assessed on an intent to treat basis. Results: The median age was 61 years (range, 32–78). 8 patients (62%) had Stage III myeloma. 11 of the 13 patients achieved an objective response yielding a response rate of 85% within 1–2 months of therapy. So far 6 patients have experienced grade 3 adverse events. These include one episode each of CD4-count < 200/mm3, anemia, neutropenia, increased liver enzymes, muscle weakness, agitation, hyperglycemia, cardiac arrhythmia, pneumonitis, and colonic perforation (underlying diverticulitis and dexamethasone suspected). No deep vein thrombosis or grade 4 or higher adverse events have been observed so far. Conclusions: Rev/Dex appears active and well tolerated in the treatment of newly diagnosed MM and is a potential alternative to Thal/Dex. However, these results are preliminary and responses are still being evaluated and need to be confirmed in the final analysis of this trial. A large randomized trial using Rev/Dex as initial therapy for MM is expected to be activated by the Eastern Cooperative Oncology Group later this year.

Abstract Abstract 3854 Poster Board III-790 Background Primary systemic amyloidosis (AL) is an incurable plasma cell disorder. Lenalidomide, especially in conjunction with dexamethasone, has been shown to be active in patients with multiple myeloma. Pomalidomide is a derivative of thalidomide that acts as an immunomodulator. Preliminary data in multiple myeloma demonstrate that this agent is highly active and well tolerated. Methods Eligible patients were accrued into an IRB approved treatment trial with pomalidomide and dexamethasone after signing informed consent. Pomalidomide (2 mg) and dexamethasone (40 mg) were scheduled to be taken orally, the former on a continuous schedule and the latter once weekly. All patients were instructed to take an aspirin daily. Patients were eligible if they had previously treated, biopsy proven, symptomatic AL. Patients were required to have measurable hematologic disease, defined as either a serum M-protein greater than 1 g/dL, a urinary M-protein greater than 200 mg/24-hours, or a serum immunoglobulin free light chain greater than 10 mg/dL. Other eligibility criteria included an ECOG PS>=2, adequate hematologic reserve (ANC>=1000/uL, platelets>=75/uL) and adequate renal function (creatinine <=2.5 mg/dL). They also were required to comply with contraceptive requirements. Patients were excluded if they had uncontrolled infection, another active malignancy, NYHA classification III or IV, a serum troponin T >0.1 ng/mL, >=grade 3 peripheral neuropathy, untreated active thrombosis, or other chemotherapy within 2 weeks of study enrollment. Thirty-four patients are to be enrolled to allow for 2 possible cancels and to provide 90% power to detect a true hematologic response rate of at least 20%. Between 11/24/08-7/28/09, 20 patients have been enrolled. Baseline characteristics and adverse events are available for 17 of the 20 enrolled patients. Results Median age was 63 years (range 52 78), with 60% male. The median time from diagnosis to study entry was 45 months (range 4.5-103). Eighty-two percent had cardiac involvement; 41% renal involvement; 18% peripheral nerve involvement; and 12% autonomic nerve involvement. The cardiac biomarker staging breakdown was: I, 13%; II, 56%; and III, 31%. Patients were heavily treated, with 100% having received prior alkylator (including prior transplant in 9), 44% prior lenalidomide, 31% prior thalidomide, and 37% prior bortezomib. Thirty-three percent of patients had non-hematological adverse events (AEs) >=grade 3 (severe) that were deemed to be at least possibly related to therapy. Thirty-three percent had >=grade 3 hematologic AEs. Neutropenia was most the most common severe hematologic AE; severe thrombocytopenia was observed in only 1 patient, and there was no severe anemia. The most common severe non-hematologic AE was fatigue, which was observed in 3 patients. The only other severe AEs, each of which was observed in one subject each, were pneumonia, weakness, dyspnea, and ascites. As of 8/14/09, 17 patients remain on active therapy. Median time on study is only 3.7 months (range 0.2-8.1). Three patients have discontinued therapy: two progressions; and one death 5 days into treatment, presumably due to cardiac amyloidosis. At the time of this writing response rates could not be calculated given the short follow-up, but hematologic responses have been observed, and details on efficacy will be presented at the meeting. Conclusions Pomalidomide is well tolerated in previously treated AL patients. More information about its activity will be provided at the meeting. Disclosures: Dispenzieri: Celgene: Research Funding. Gertz:Celgene: Honoraria. Kumar:Celgene: Research Funding. Rajkumar:Celgene: Research Funding. Witzig:Novartis: Research Funding. Greipp:Celgene: Research Funding. Fonseca:Celgene: Consultancy. Bergsagel:Celgene: Consultancy. Mikhael:Celgene: Research Funding. Roy:Celgene: Research Funding. Lacy:Celgene: Research Funding.

Abstract Abstract 4876 Background Recent studies have found obesity to be associated with a 1.5- to 2-fold elevated risk of developing multiple myeloma. This is of particular interest given that elevated levels of the pro-inflammatory cytokine interleukin (IL)-6 have been found in obese persons, and, at the same time, IL-6 has well-known proliferative and anti-apoptotic effects on monoclonal plasma-cells. Also insulin-like growth factors (IGFs) have been proposed to play a role since obesity often causes insulin resistance, which in turn modulates the bioavailability of IGF-1 Similar to IL-6, prior studies have found IGF-1 to have both growth and survival effects on monoclonal plasma-cells. Based on these facts, we have speculated that obesity might increase the risk of the multiple myeloma precursor monoclonal gammopathy of undetermined significance (MGUS), or, alternatively, that obesity may increase the risk for transformation from MGUS to multiple myeloma. We conducted the first large screening study designed to assess the association between obesity and MGUS among almost 2,000 African-American and Caucasian women. Methods We included 1000 African-American and 996 Caucasian women (age 40-79, median 48 years) from the Southern Community Cohort Study to assess MGUS risk in relation to obesity. Per our sampling strategy, about 50% of the participants were obese. Medical record-abstracted weight and height (measured on the day of study enrollment) and self-reported values had very high concordance (Pearson correlation >0.95). Serum samples from all subjects were analyzed by electrophoresis performed on agarose gel; samples with a discrete or localized band were subjected to immunofixation. Using logistic regression models, we estimated odds ratios (ORs) as measures of risk. Results Among all study participants, 39 (3.9%) African-Americans and 21 (2.1%) Caucasians were found to have MGUS, yielding a 1.9-fold (95%CI 1.1-2.3; p=0.021) higher risk of MGUS among African-Americans (vs. Caucasians). On multivariate analysis, we found obesity (OR=1.8, 95%CI 1.03-3.1; p=0.039), African-American race (OR=1.8, 95%CI 1.04-3.1; p=0.037), and increasing age (quartiles: ≥55 vs. <43 years) (OR=2.5, 95%CI 1.1-5.7; p=0.028) to be independently associated with an excess risk of MGUS. Another interesting finding was that the distribution of the monoclonal immunoglobulin isotype usage among African-American and Caucasian women was significantly different (p=0.007). Their respective rates were: IgG in 79.5% and 71.3 %; IgA in 7.7% and 0%; IgM in 7.7% and 19%; biclonal in 5.1% and 4.7%; and triclonal in 0% and 4.7%. The distribution of serum light-chain types between the two races was also significantly different (P=0.003, chi-square test): kappa in 53.8% and 47.6%; lambda in 43.6% and 42.8%; biclonal 2.6% and 4.7%; and triclonal in 0% and 4.7%. Conclusions Our finding that MGUS is twice as common among obese (vs. non-obese) women, and independent of race, supports the hypothesis that obesity is etiologically linked to myelomagenesis and may have public health impact. The observed 2-fold excess of MGUS among African-Americans (vs. Caucasians) of similar socio-economic status, coupled with other recent studies supports a role for susceptibility genes as the cause for racial disparity in the prevalence of MGUS. Disclosures No relevant conflicts of interest to declare.

Abstract Abstract 615 Background: Trials comparing efficacy of standard melphalan prednisone (MP) therapy with MP plus thalidomide (T) in the transplant ineligible, elderly patients with multiple myeloma have provided conflicting evidence. While there is greater agreement with regard to superior response rates (RR) with the addition of T to MP in elderly patients, the impact on progression free survival (PFS) and overall survival (OS) is less clear with some trials showing an improvement in PFS and/or OS with MPT and others demonstrating no difference in outcomes. We performed a systematic review to integrate the existing outcome data related to the efficacy of MP vs. MPT using a meta-analytic approach. Methods: A comprehensive search of electronic database through July 31st, 2009 was performed for publications, abstracts and presentations to identify randomized controlled trials (RCTs) comparing MP with MPT. A meta-analysis was performed by pooling results on clinical endpoints of RR, PFS and OS reported in all the identified RCTs under a random effects model. We did not have access to individual patient data from these trials. Results: Overall, five prospective RCTs (3 published articles and 2 abstracts) comparing MP with MPT regimen and comprising a total of 1571 patients were identified. For the endpoints of OS and PFS, data were extractable only from 4 RCTs (abstract by Gulbrandsen et al. was excluded). The Bregg and Egger funnel plot for OS demonstrated a symmetric distribution (P = 0.6) indicating no significant publication bias. The test of heterogeneity among all RCTs was statistically significant in the estimate of RR (tau2=0.21; chi2=16.33; p=0.003 (df=4); I2 = 75.5%), but not significant for the estimates of PFS (tau2=0.01; chi2=4.61; p=0.2 (df=3); I2 = 34.9%), and OS (tau2=0.02; chi2=5.53; p=0.14 (df=3); I2 = 45.8%). As expected, the pooled odds ratio of responding to treatment with MP versus MPT was 0.307 (P&lt;0.001) indicating that MP was worse than MPT in achieving at least a partial response. The pooled hazard ratios (HR) for PFS and OS were 1.59 (p&lt;0.001) and 1.34 (p=0.006), respectively (see table for forest plots) in favor of MPT. Conclusion: Our meta-analysis implies that in previously untreated, transplant ineligible elderly patients with multiple myeloma, the addition of thalidomide to melphalan-prednisone demonstrates improved RR, PFS and OS compared with the use of melphalan-prednisone alone. Although the results from a comprehensive individual patient data pooled analysis would give a more precise estimate, our analysis suggests that MPT is superior to MP in terms of response and survival. Disclosures: Dispenzieri: Celgene: Research Funding. Gertz:Celgene: Honoraria. Kumar:celgene, genzyme, millennium, novartis, bayer: Research Funding; genzyme: Membership on an entity's Board of Directors or advisory committees.

The quantitative assay for free light chains (FLC) is a recently introduced commercial product (FREELITETM, The Binding Site, Ltd.) that has been reported to be sensitive and specific for detecting and monitoring free light chain diseases such as primary systemic amyloidosis (AL), light chain deposition disease (LCDD), non-secretory multiple myeloma (NSMM), and LCMM (light chain multiple myeloma). We have prospectively evaluated the test performance in clinical practice. Results : In 2003, our Clinical Laboratory received samples for FLC assays from 1020 Mayo Clinic patients. The majority of these patients (88%) had plasma cell disorders (PCD). All 120 patients who did not have PCD had normal K/L FLC ratios. Among these, 52 had non-AL amyloidosis: localized amyloid (23), hereditary (16), senile (6), secondary (3), and amyloid of unknown type (4). The 68 other patients who did not have a PCD were being tested because of peripheral neuropathy, rule out AL, anemia, proteinuria, lymphoproliferative disease, and a number of other indications with small numbers of patients (n=13). Among the monoclonal gammopathy patients were 330 with MM, 269 AL, 115 MGUS, 72 SMM, 22 plasmacytomas, 20 NSMM, 9 macroglobulinemia, 7 LCDD, and a variety of other diagnoses with smaller numbers of patients. The sensitivity of the K/L FLC ratio was 100% in LCDD (7/7) and 70% in NSMM (14/20). The 6 NSMM patients with normal K/L FLC ratios had all been treated with SCT and 5 of the 6 had achieved hematologic remission by bone marrow plasma cells. Among the 110 AL patients who had not been previously treated and who had a FLC assay performed within 120 days of diagnosis, the sensitivity of the K/L FLC ratio was 92% compared to 71% for serum IFE and 84% for urine IFE. Using all 3 assays, there was 99.1% (109/110) sensitivity for detecting monoclonal light chain in AL. Conclusion : The performance of the FLC assay in this prospective analysis matches the results from published retrospective validation studies.

Abstract Abstract 4953 Introduction Primary systemic (AL) amyloidosis occurs as a result of the production a monoclonal protein by a clonal plasma cell or B-cell proliferative disorder. Reduction or complete eradication of the underlying clonal cell disorder is essential for an organ response. Melphalan/ dexamethasone or high dose chemotherapy with autologous hematopoietic stem transplant is currently considered the standard of care. Bortezomib a proteosome inhibitor is effective in reducing or eradication clonal plasma cells and has been shown to produce high complete hematologic response (CHR) rates in multiple myeloma. We therefore hypothesized that Bortezomib will produce a high CHR rate and hence a higher organ response in patients with AL. Material and Methods Our amyloidosis data base which is prospectively collected was searched for patients with primary amyloidosis (AL) who were treated with Bortezomib containing regimen during their disease course. We identified 20 patients. We then assessed clinical features, hematologic and organ response based on the amyloidosis consensus working group criteria. We also evaluated overall survival and time to next therapy. Results We identified 20 patients who received a Bortezomib containing regimen. The median age at diagnosis was 57 yr (range 43 - 79). There were 12 (60%) males. All patients had clonal plasma cell disorder except one patient with lymphoplasmacytic lymphoma. Median bone marrow plasma cell involvement was 10%. The amyloid protein was Lambda light chain in 12 patients and Kappa in 6 patients. Data was missing in 2 patients. The median serum m-spike was 0.5g/dL (range 0 to 3.5). The median number of organs involved was 1 (range 1 – 4). Nine patients had 2 or more organs involved. The specific organs involved were Kidney (13), Cardiac (12), Nerve (5) and liver (2). Median number of prior regimen was 1(range 0 to 3). Seven patients had received no prior therapy. The remaining 13 patients had received various treatments including oral Melphalan/dexamethasone (9), Lenalidomide/dexamethasone (3), Thalidomide/dexamethasone (1) and one patient who received R-CHOP for underlying lymphoplasmacytic lymphoma. Four patients had received a prior autologous stem cell transplant. The median time form diagnosis to Bortezomib treatment was 5 months. The Bortezomib regimen was mainly Bortezomib/dexamethasone (17patients), Bortezomib/Thalidomide/dexamethasone (1), Bortezomib/cyclophosphamide/dexamethasone (1). The Bortezomib was given mainly in the standard dosing 1.3mg/m2 days 1, 4, 8, and 11. Treatment was well tolerated. Hematologic response was seen in 17 patients including CHR (11), VGPR (3), PR (1), and MR (2). Thus resulting in a better than PR response of 75%. Three patients had no response. The median number of cycles to best hematologic response was 4 (range 1 – 9). The median total number of cycles administered was 4 (range 1 – 10). Organ response was seen in 10 patients (50%). These were mainly partial responses was seen primarily in patients with renal amyloidosis. Median time to next treatment was 7.5 months (95% CI: 4-9). Seven patients have received further therapy after their Bortezomib treatment. Three patients received consolidation treatment with Autologous PBSCT although they had all achieved VGPR or CHR. The other four received salvage chemotherapy for disease progression or lack or response, BMT (1), FCR (1), Pomalidomde/dexamethasone (1) and Melphalan/dexamethasone (1). Median follow up of all patients from diagnosis is 12 months (range 2 – 64). The median survival from diagnosis is estimated at 44.7 months (95% CI; 29.1 – 64.8). Median follow up from Bortezomib treatment is 5 months and median survival from Bortezomib treatment has not been reached. Conclusion Bortezomib produced high hematologic response in this population of patients. Organs response was seen in 50% of patients. The durability of these responses is not known, because of the short follow up time. This study suggests that Bortezomib containing regimen may be beneficial in amyloidosis patients. A larger prospective study, looking at single agent Bortezomib or in combination with alkylator agents compared to standard melphalan/dexamethasone or autologous stem cell transplant is needed to help define the role of Bortezomib in primary amyloidosis. Disclosures Lacy: celgene: Research Funding. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 3884 Poster Board III-820 Background and Objective Thalidomide/dexamethasone (thal/dex) combination has shown high activity in newly diagnosed multiple myeloma (MM) (Rajkumar SV. at al, J Clin Oncol 2006;24:431-436). In newly diagnosed patients, lenalidomide/dexamethasone (len/dex) has demonstrated superiority compared with high-dose dexamethasone alone (Zonder JA et al, Blood 2007;110:77). Although both thal/dex and len/dex are active in newly diagnosed MM, no randomized trial has been reported comparing these two regimens, and unfortunately none are ongoing or planned. We compared the efficacy and the toxicity of thal/dex and len/dex as primary therapy in 411 newly diagnosed MM patients treated at the Mayo Clinic. Patients and methods 411 consecutive patients seen at Mayo Clinic between 2001 and 2008, who received induction with thal/dex (n=183) or len/dex (n=288) were retrospectively studied. Thalidomide was given at a dose ranging from 100 mg/day to 400 mg/day continuously; the lenalidomide dose was 25 mg/day, days 1-21 on a 28-day cycle. All patients received dexamethasone, either at high-dose (40 mg orally on days 1-4, 9-12, and 17-20) or at low-dose (40 mg orally day 1, 8, 15, 22); each cycle was repeated every 4 weeks. In addition, a case-matched subgroup analysis that adjusted for age, gender and transplantation status was performed among patients who received high-dose dexamethasone comparing the thal/dex (n=72) and len/dex (n=72) groups. Outcome was analyzed on an intention-to-treat basis. The Chi-square or the rank sum tests were used to compare variables. Time-to-event analysis was performed using the Kaplan-Meier method and all comparisons were determined by the log-rank test and by the Cox proportional hazards model. Results On intention-to-treat analysis, of 411 patients, 80.3% versus 61.2% patients, respectively in the len/dex group and in the thal/dex group (p < 0.001), achieved at least a partial response. A significant difference between the 2 groups was found in terms of both very good partial response or better (34.2% vs 12.0%, p < 0.001) and complete response rate (13.6% vs 3.3%, p < 0.001). Duration of therapy was significantly longer in len/dex patients as compared to thal/dex patients: 36.7% vs 12.6% of patients who did not stop treatment to receive SCT were still receiving therapy at 1 year (p < 0.001).Time-to-progression was significantly better in the len/dex group than in patients receiving thal/dex (median 27.4 vs 17.2 months, HR 0.64; 95% CI 0.44-0.93; p = 0.019). Similarly, progression-free-survival was significantly higher in len/dex patients (median 26.7 vs 17.1 months, HR 0.69; 95% CI 0.48-0.98; p = 0.036). This translated into an increase in overall survival (OS) (median not reached for len/dex group compared to 57.2 months in thal/dex patients, HR 0.60; 95% CI 0.40-0.92; p = 0.018). Survival advantages were evident in patients presenting with International Staging System Stage (ISS) I/II (HR 0.57; 95% CI 0.32-1.00; p = 0.052) at diagnosis but not in patients with ISS stage III in subgroup analysis. There was a trend toward better OS in len/dex group compared to thal/dex group both for patients who underwent transplant and for patients who did not. A similar rate of patients experienced at least one grade 3 or higher adverse event (57.5% vs 54.6% in len/dex and thal/dex groups, respectively, p = 0.568). However, the toxicity profile was different in the two groups: major grade 3-4 toxicities of len/dex were hematological, in particular neutropenia (14% with len/dex vs 0.6% with thal/dex, p<0.001) while the most common toxicities in thal/dex were venous thromboembolism (15.3% vs 9.2%, p = 0.058) and peripheral neuropathy (10.4% vs 0.9%, p < 0.001). The data on efficacy and safety shown above were also confirmed in the subgroup case-matched analysis which included only high-dose dexamethasone patients. Conclusions This cohort study shows the superiority of len/dex in terms of response rates and survival, compared to thal/dex. The toxicity profile of the 2 regimens is different and len/dex treatment, although more active, was not associated with increased toxicity (grade 3-4 AEs). These data need to be carefully evaluated and randomized prospective phase III studies are necessary to confirm these results and determine the optimal initial therapy for MM. Disclosures: Off Label Use: research drugs in combination to standard care. Lacy:celgene: Research Funding. Gertz:celgene: Honoraria; genzyme: Honoraria; millenium: Honoraria; amgen: Honoraria. Kumar:celgene: Research Funding; millenium: Research Funding; bayer: Research Funding; Novartis: Research Funding; Genzyme: Research Funding. Dispenzieri:celgene: Research Funding. Bergsagel:amgen: Membership on an entity's Board of Directors or advisory committees; genetech: Membership on an entity's Board of Directors or advisory committees; merck: Research Funding; celgene: Membership on an entity's Board of Directors or advisory committees. Witzig:celgene: Research Funding. Fonseca:medtronic: Consultancy; genzyme: Consultancy; celgene: Consultancy; amgen: Consultancy; BMS: Consultancy; otsuka: Consultancy. Greipp:celgene: Research Funding.

Abstract Abstract 429 Background: Patients with MM who have progressed after multiple novel agents have limited treatment options. Pomalidomide (CC4047) is the newest immunomodulatory (IMiD) agent that has demonstrated response rates of 63% in a Phase 2 trial of Pom/dex in patients with relapsed MM (in press, JCO). To better define the response rate in this group, we treated an additional cohort of patients who were truly resistant/refractory to lenalidomide. Methods: To be eligible, patients must:be refractory to lenalidomide therapy defined as relapsing on or within 60 days of stopping lenalidomide. Pomalidomide was given orally 2 mg daily on days 1–28 of a 28-day cycle. Dexamethasone was given orally at a dose of 40 mg daily on days 1, 8, 15 and 22 of each cycle. Response was assessed by the International Myeloma Working Group Uniform Response criteria. All patients received aspirin 325 mg daily as prophylaxis against DVT. Pom/dex regimen would be declared promising if we observed at least 4 confirmed responses out of 34 patients based on a single stage Fleming design. Results: 34 patients (23 male and 11 female) resistant/refractory to lenalidomide were enrolled. The median age was 62 years (range, 39-77). The median time from diagnosis to enrollment was 62 months (range 8-179). 12 patients had high risk molecular markers including loss of 17p (6 pts), t(4;14) (1 pt) and del 13 by cytogenetics (5 pts). 70% had ≥3 prior regimens including 38% with ≥5 prior regimens; 56% had prior thalidomide, 59% had prior bortezomib, and 68% had prior SCT. Toxicity (at least possibly related to treatment) was mild and consisted primarily of myelosuppression: grade 3/4 neutropenia (21%); grade 3 thrombocytopenia (9%); and grade 3 anemia (12%). Grade 3/4 non-hematologic toxicities occurred in 24%: pneumonia (3%), non-infectious pneumonitis (3%), hyperglycemia (3%), edema(3%), fatigue(9%) skin rash(3%). Neuropathy occurred in 18% (12% grade 1; 6% grade 2). No thromboembolic events have occurred so far. Nine (26%) patients were confirmed responders (all PR), surpassing the threshold for a positive trial, and 18 (53%) had SD. With a median follow-up of 4 months (range:0-8), 65% remain progression free; 88% remain alive; and 12% have died, all due to progressive MM. Conclusions: Pom/dex is active and well tolerated in this heavily pre-treated population of lenalidomide-refractory MM patients. The majority of patients have not progressed and objective responses are seen in 26%. This study confirms that pomalidomide has non-cross resistance with lenalidomide and offers benefit for patients who have relapsed after other novel therapies. Disclosures: Lacy: Celgene: Research Funding. Gertz:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Kumar:celgene: Honoraria; millenium: Honoraria, Membership on an entity's Board of Directors or advisory committees. Bergsagel:Genentech, Inc.: Consultancy; Amgen: Consultancy; Celgene: Consultancy; Merck: Research Funding. Stewart:Takeda-Millenium, Celgene, Novartis, Amgen: Consultancy; Takeda, Millenium: Research Funding; Genzyme, Celgene, Millenium, Proteolix: Honoraria.

Abstract Background: The combination of lenalidomide and dexamethasone (RD) has been shown to be highly effective as initial therapy for multiple myeloma. More recently, a phase III trial demonstrated improved survival with use of lenalidomide and low dose dexamethasone (Rd). Further improvements by incorporating other active agents may increase the depth of response and may improve long-term outcome. We report the results from a phase II trial combining lenalidomide and low dose dexamethasone with cyclophosphamide (RCd) as initial therapy for newly diagnosed MM. Methods: The trial was initiated in July 2006 and completed the initial target accrual of 33 patients by July 2007 (Cohort 1). Due to high rate of dose reductions in cohort 1, between July 2007 and May 2008 an additional 20 patients were enrolled with lower doses of cyclophosphamide (Cohort 2). The treatment protocol consisted of lenalidomide given orally at a dose of 25 mg daily on days 1–21 of a 28-day cycle. Dex was given orally at a dose of 40 mg on days 1, 8, 15, and 22 of each cycle. Cyclophosphamide at a dose of 300 mg/m2 was given on days 1, 8, and 15 of each cycle in cohort 1 and 300 mg on days 1, 8, and 15 of each cycle in cohort 2. Patients also received an aspirin once daily as thromboprophylaxis. Response was defined as a decrease in serum monoclonal (M) protein by 50% or higher and a decrease in urine M protein by at least 90% or to a level less than 200 mg/24 hours. Responses were assessed on intent to treat basis. Results: 53 patients were enrolled. The median age was 64 years (range, 37–82). 14 patients (29%) had ISS stage III disease. The median number of cycles was 4 (range: 1 – 20). The best response based on all enrolled patients on an intent to treat basis was 83%, including CR:1 (2%), VGPR: 20 (38%), PR: 23 (43%), and less than PR: 9 (17%). The CR plus VGPR rate was 40%. Among the 20 patients in cohort 2 who were enrolled after optimization of the cyclophosphamide dosing, 16 (80%) have already achieved a partial response or better with 17 patients in this cohort still receiving study treatment. Overall, 25 of the 53 enrolled patients have discontinued study treatment. Reasons for ending treatment are: completed study per protocol (14), disease progression (5), adverse event (3) and alternate treatment (3). This includes 3 patients from cohort 2, one completed treatment per protocol, one went to alternate therapy and one patient went off for progression. Hematological toxicity was the most common with grade 4 toxicity seen in 8 patients (only 1 from cohort 2). Non-hematological toxicities included neuropathy, diarrhea, cystitis, and thrombosis. There were 6 patients with grade 4 non-hematological toxicities (none from cohort 2) attributed to the drug (thrombosis, confusion, depression and sepsis). Thirteen patients had dose adjustments, most commonly due to hematological toxicity attributed to lenalidomide or cyclophosphamide. One patient has died off study, of intracranial hemorrhage. The median follow-up for the remaining patients is 7.8 months. Conclusions: The combination of lenalidomide, cyclophosphamide, and dexamethasone (RCd) has excellent activity in the setting of newly diagnosed myeloma. Seventeen patients continue on study and the response rates are likely to be higher with additional followup. Myelosuppression was a significant toxicity leading to dose reductions and cycle delays, and is lower with decreased dose of CTX in cohort 2 without any apparent loss of responses.

Abstract Background: Thalidomide and its analogue lenalidomide have high response rates among patients with newly diagnosed as well as previously treated myeloma. Pomalidomide (CC4047) is the newest immunomodulatory (IMiD) agent that has shown single-agent activity in phase I studies. We report on the first Phase 2 trial of pomalidomide combined with low dose dexamethasone (Pom/dex) in patients with relapsed or refractory multiple myeloma. Methods: 37 patients (21 male and 16 female) were enrolled. Pomalidomide was given orally 2 mg daily on days 1–28 of a 28-day cycle. Dexamethasone was given orally at a dose of 40 mg daily on days 1, 8, 15 and 22 of each cycle. Response was assessed by the International Myeloma Working Group Uniform Response criteria. All patients received aspirin 325 mg daily as prophylaxis against DVT. Results: The median age was 66 years (range, 40 – 88). All patients were evaluable for response and toxicity, and all analysis were done on intent to treat basis. All patients had received prior therapy; 38% had 3 prior regimens; 35% had 2 prior regimens and 27% had one prior regimen. 76% had previous autologous stem cell transplant (ASCT) and 24% had 2 prior ASCT. 62% had previous IMiD therapy. Toxicity was mild and consisted primarily of myelosuppression. Grade 3 neutropenia occurred in 31%; grade 3 thrombocytopenia 3%; grade 3 anemia 3 %. Other grade 3/4 toxicities seen in less than 5% pts included: diarrhea, atrial fibrillation, pneumonia, dehydration and renal insufficiency. 16 % had grade 1/2 neuropathy. No grade 3 neuropathy was seen and there have been no thromboembolic events. Thirty (81%) patients are continuing study treatment. Seven patients have discontinued treatment due to: disease progression (5), died on study (1) and the medical doctor’s discretion (1). Twenty three of 37 patients (62%) achieved an objective response to therapy; including 9 (24%) with VGPR; 14 patients (38%) with PR; 6 (16%) with stable disease. Objective responses were seen in 4 of 13 patients (29%) who were refractory to lenalidomide. Conclusions: Pomalidomide plus dexamethasone (Pom/dex) is highly active and well tolerated for treatment of relapsed/refractory multiple myeloma with an objective responserate of 62%, including a 29% response rate among patients who are lenalidomiderefractory.