Abstract: Persons of African ancestry (AA) have a twofold higher risk for multiple myeloma (MM) compared with persons of European ancestry (EA). Genome-wide association studies (GWASs) support a genetic contribution to MM etiology in individuals of EA. Little is known about genetic risk factors for MM in individuals of AA. We performed a meta-analysis of 2 GWASs of MM in 1813 cases and 8871 controls and conducted an admixture mapping scan to identify risk alleles. We fine-mapped the 23 known susceptibility loci to find markers that could better capture MM risk in individuals of AA and constructed a polygenic risk score (PRS) to assess the aggregated effect of known MM risk alleles. In GWAS meta-analysis, we identified 2 suggestive novel loci located at 9p24.3 and 9p13.1 at P & lt; 1 × 10−6; however, no genome-wide significant association was noted. In admixture mapping, we observed a genome-wide significant inverse association between local AA at 2p24.1-23.1 and MM risk in AA individuals. Of the 23 known EA risk variants, 20 showed directional consistency, and 9 replicated at P & lt; .05 in AA individuals. In 8 regions, we identified markers that better capture MM risk in persons with AA. AA individuals with a PRS in the top 10% had a 1.82-fold (95% confidence interval, 1.56-2.11) increased MM risk compared with those with average risk (25%-75%). The strongest functional association was between the risk allele for variant rs56219066 at 5q15 and lower ELL2 expression (P = 5.1 × 10−12). Our study shows that common genetic variation contributes to MM risk in individuals with AA.

Abstract: Few treatments options are available for patients (pts) with relapsed/refractory multiple myeloma (RRMM) who have previously been treated with lenalidomide (LEN) and bortezomib (BORT), and their prognosis is poor. Pomalidomide (POM) is a distinct IMiD® immunomodulatory agent with a mechanism of action consisting of direct anti-myeloma, stromal-support inhibitory, and immunomodulatory effects. In randomized phase 2 and 3 trials (MM-002 and MM-003), POM plus low-dose dexamethasone (POM+LoDEX) demonstrated marked efficacy in RRMM pts who had received multiple prior therapies, including LEN and BORT. This side-by-side analysis presents the most recent survival and safety data from these trials. Methods The MM-002 and MM-003 trials enrolled pts with ≥ 2 prior therapies, including LEN and BORT. In MM-002, pts received POM (4 mg/day on days 1–21 of each 28-day cycle) alone or in combination with LoDEX (40 mg/week). In MM-003, pts were randomized 2:1 to receive POM+LoDEX or high-dose DEX alone (HiDEX) (40 mg/days 1–4, 9–12, 17–20 in a 28-day cycle); HiDEX was chosen as the comparator to isolate the effects of POM, as at the time of trial design it was the standard salvage therapy for heavily pretreated pts. Thromboprophylaxis was required for all pts treated with POM and pts at high risk of developing venous thromboembolism. Data cutoff was February 1, 2013 for MM-002 and March 1, 2013 for MM-003. The primary endpoint in both trials was progression-free survival (PFS). Secondary endpoints included overall survival (OS), response rates, duration of response, and safety. Results In each study, pts had received a median of 5 prior therapies (range 1-17), and all pts had received prior LEN and BORT. In MM-002, 113 pts were treated with POM+LoDEX and 108 were treated with POM alone (60% of POM alone pts subsequently received DEX). A total of 79% of pts were LEN refractory; 62% were refractory to both LEN and BORT; and 35% had received LEN as their last prior therapy. With a median follow-up of 14.2 months (mos), median PFS was 4.2 mos, OS was 16.5 mos, and overall response rate (ORR, defined as at least a partial response) was 33% with POM+LoDEX (Table 1). In MM-003, 302 pts were treated with POM+LoDEX and 153 pts were treated with HiDEX (50% of HiDEX pts subsequently received POM). A total of 94% of pts were LEN refractory; 74% were both LEN and BORT refractory; and 29% had received LEN as their last prior therapy. Survival outcomes were similar in MM-003; with a median follow-up of 10 mos, median PFS was 4.0 mos, OS was 12.7 mos, and ORR was 31% with POM+LoDEX. In both trials, LEN as last prior therapy did not impact response, PFS, or OS vs the overall population. Commonly observed adverse events (AEs) are presented in Table 2 for pts treated with POM+LoDEX. Grade 3 and 4 neutropenia was 28% and 13% in MM-002, and 26% and 22% in MM-003 for the POM+LoDEX arms, respectively. AEs were generally manageable for POM+LoDEX in MM-002 and MM-003 with dose interruptions (67% for both) and reductions (29% and 26%, respectively), and standard supportive care, including growth factor support (46% and 43%), red blood cell transfusions (45% and 49%), platelet transfusions (14% and 20%), and anti-infective agents (89% in both trials). Rates of POM discontinuation due to treatment-related AEs were low (2–4% with POM+LoDEX). In MM-002 and MM-003, 49% and 51% of pts in the POM+LoDEX arms experienced neutropenia of any grade. With appropriate AE management, 9% and 23% had dose interruptions, 4% and 8% had dose reductions, and 1 pt in both MM-002 and MM-003 discontinued due to neutropenia. Febrile neutropenia developed in 3% and 10% of pts; 1% and 4% had dose interruptions, 0% and 2% had dose reductions, and no pts discontinued due to febrile neutropenia in the MM-002 and MM-003 studies, respectively. The majority of infections occurred in the absence of neutropenia of any grade (54% in MM-002 and 66% in MM-003). The rate of POM discontinuation due to infection was low (1% in MM-002 and 2% in MM-003). Conclusion In both the MM-002 and MM-003 trials, POM+LoDEX consistently extended PFS in advanced RRMM pts. PFS, OS, and ORR were not negatively impacted in patients who were refractory to LEN or BORT, even as last prior therapy. Both trials demonstrated that with dose modifications and supportive care POM was well tolerated, leading to few discontinuations. POM+LoDEX should be considered a standard of care for pts with advanced RRMM who have exhausted LEN and BORT. Disclosures: Siegel: Celgene Corporation: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Onyx: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau; Millennium: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Richardson:Millennium: Membership on an entity’s Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity’s Board of Directors or advisory committees; Celgene Corporation: Membership on an entity’s Board of Directors or advisory committees. Dimopoulos:Celgene Corporation: Honoraria, Membership on an entity’s Board of Directors or advisory committees. Chen:Celgene Corporation: Consultancy, Honoraria, Research Funding. Song:Celgene Corporation: Honoraria, Membership on an entity’s Board of Directors or advisory committees, Research Funding, Speakers Bureau. Vij:Onyx: Consultancy, Research Funding; Millenium: Speakers Bureau; Celgene Corporation: Consultancy, Research Funding, Speakers Bureau. Bahlis:Celgene Corporation: Consultancy, Honoraria, Research Funding. Baz:Millenium: Research Funding; Bristol Myers Squibb: Research Funding; Novartis: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Celgene Corporation: Research Funding. Hofmeister:Celgene Corporation: Membership on an entity’s Board of Directors or advisory committees, Speakers Bureau. Weisel:Celgene Corporation: Consultancy, Honoraria, Research Funding. Jagannath:Millennium: Honoraria; Celgene Corporation: Honoraria. Lonial:Millennium: Consultancy; Novartis: Consultancy; Bristol Myers Squibb: Consultancy; Sanofi: Consultancy; Onyx: Consultancy; Celgene Corporation: Consultancy. Delforge:Celgene Corporation: Honoraria. Talpaz:Ariad, Sanofi, Novartis: Membership on an entity’s Board of Directors or advisory committees; Ariad, Novartis, BMS, Pfizer: Speakers Bureau; Ariad, BMS, Sanofi, INCYTE: Research Funding. Moreau:Celgene Corporation: Honoraria, Speakers Bureau. San Miguel:Jansen, Celgene Corporation, Onyx, Novartis, Millenium: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees. Karlin:Janssen: Honoraria; Celgene Corporation: Consultancy, Expert board committee Other, Honoraria. Goldschmidt:Celgene Corporation, Janssen, Novartis: Consultancy, Honoraria, Research Funding. Oriol:Celgene Corporation: Consultancy. Alegre:Janssen: Membership on an entity’s Board of Directors or advisory committees, Research Funding; Celgene Corporation: Membership on an entity’s Board of Directors or advisory committees, Research Funding. Cavo:Millennium: 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; Onyx: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Bristol-Myers Squibb: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees; Celgene Corporation: Consultancy, Honoraria, Membership on an entity’s Board of Directors or advisory committees. Martinez-Lopez:Celgene Corporation: Honoraria, Research Funding. Lacy:Celgene Corporation: Research Funding. Chen:Celgene Corporation: Employment, Equity Ownership. Casey:Celgene Corporation: Employment, Equity Ownership. Sternas:Celgene Corporation: Employment, Equity Ownership. Zaki:Celgene Corporation: Employment, Equity Ownership. Jacques:Celgene Corporation: Employment, Equity Ownership. Anderson:Onyx: Consultancy, Equity Ownership; Gilead: Consultancy, Equity Ownership; sanofi aventis: Consultancy, Equity Ownership; Oncopep: Consultancy, Equity Ownership; Acetylon: Consultancy, Equity Ownership; Celgene Corporation: Consultancy, Equity Ownership.

Abstract: Multiple myeloma (MM) is 2-3 times more common among African-Americans compared to non-Hispanic whites. The 2-3-fold increased risk among family members of cases suggests a genetic contribution to risk. Genome-wide association studies (GWAS) in populations of European ancestry have identified seven novel risk loci at 2p23.3 (rs6746082), 3q26.2 (rs10936599), 3p22.1 (rs1052501), 6p21.32 (rs2285803), 7p15.3 (rs4487645), 17p11.2 (rs4273077) and 22q13.1 (rs877529) (Broderick, et al. Nat Genet, 2011, Chubb, et al. Nat Genet, 2013), three of which were replicated in another European series (Martino et al., Br J Haematol, 2012). Here we examined the index signals and conducted fine-mapping for each locus in a case-control study of 1,049 multiple myeloma cases and 7,084 controls of African ancestry to identify better markers of risk and novel independent loci in seven previously reported regions in this high risk population. Incident cases were recruited from 10 clinical centers and SEER cancer registries from 2011 to 2013 and genotyped using the Illumina HumanCore GWAS array. Control data were obtained from previous genome-wide studies of breast and prostate cancer, genotyped using the Illumina 1M-Duo in 4425 male controls from the African Ancestry Prostate Cancer Consortium (consisting of 14 independent studies) and 2632 female controls from a breast cancer GWAS of African-American women (consisting of 9 independent studies). Imputation to 1000 Genomes (March 2012 release) was conducted for regions around six of the previously identified single nucleotide polymorphisms [SNPs] (the HLA region harboring rs2285803 is still being imputed, results will be presented). A case-control analysis of SNPs/indels 〉 1% frequency within 250 kb of each index variant was conducted using unconditional multivariable logistic regression adjusting for age, sex and five leading principal components. Region-specific alpha levels were determined through permutation tests. The minimum alpha level across the six regions was α=0.002. All previously reported risk variants were common in African-Americans (minor allele frequency [MAF] 〉 0.05). For five of the six SNPs, we had ≥94% power to detect the same effect observed in non-Hispanic whites, and 64% power for the less common variant rs10936599 (MAF=0.07). We observed directionally consistent effects (odds ratio [OR] 〉 1) for the six risk variants tested, with three replicating at p≤0.05 (7p15.3, p=1.4x10-7; 17p11.2, p=0.05; 22q13.1, p=0.02). For three of the six regions, we observed better markers of risk in African-Americans that were correlated with the index SNP in Europeans (7p15.3, rs56333627, p=1.5x10-5, r2=0.89; 17p11.2, rs34562254, p=2.9x10-3, r2=0.90; 22q13.1, rs2092410, p=1.1x10-4 r2=.71). The missense variant identified in the 17p11.2 region (rs34562254, Pro251Leu) is located in TNFRSF13B, which encodes the protein TACI, a B cell surface receptor which plays a role in B cell maturation, apoptosis and antibody production by inducing activation of transcription factors including NFAT and NFκβ. In addition, there is evidence suggesting that TACI is involved in MM pathogenesis. Our results demonstrate that many of the risk loci for MM found in European ancestry populations are also risk loci in men and women of African ancestry and that by fine-mapping, we are able to identify variants that better capture risk in populations of African ancestry. Disclosures Terebelo: Celgene Corp: Membership on an entity's Board of Directors or advisory committees. Lonial:Millennium: The Takeda Oncology Company: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Novartis: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Onyx Pharmaceuticals: Consultancy, Research Funding.