Fiala, Mark A.

Abstract Introduction Proteasome inhibitors (PIs) and immunomodulatory drugs (IMiDs) have significantly improved survival in patients with multiple myeloma (MM). Refractoriness to PIs and IMiDs results in poor outcomes with a median survival of about 13 months.Daratumumab and isatuximab are CD38-targeting monoclonal antibodies (MoABs) with remarkable activity in relapsed and refractory MM. The outcome of MM patients in US clinical practice who becomes refractory to CD38 MoABs is unknown. The aim of this multicenter, retrospective study is to investigate the natural history of patients with MM who become refractory to CD38 MoABs (Monoclonal Antibodies in Multiple Myeloma: Outcomes after Therapy Failure: MAMMOTH study). Methods We identified patients from 14 academic institutions in the US with diagnosis of active MM and refractory to daratumumab or isatuximab, administered alone or in combination. Patients were considered refractory to CD38 MoAB if treated with at least 4 weeks of therapy and had evidence of progressive disease (PD) while on therapy or within 60 days after last dose. The time when patients met the above criteria of progression was defined as time zero (T0). Data including patient-disease characteristics and all therapies administered before and after T0 were collected with an electronic platform and submitted to peer-based quality check for completeness and internal consistency. For survival outcome analysis, patients were classified into three groups: "Penta-refractory" (refractory to 1 CD38 MoAB + 2 PIs + 2 IMiDs), "Triple-refractory and quad-refractory" (refractory to 1 CD38 MoAB + 1 PI + 1/2 IMiDs, or 1 CD38 MoAB + 1/2 PIs + 1 IMiD), and "Not triple-refractory" (refractory to 1 CD38 MoAB, and not both of a PI and an IMiD). Responses were evaluated using the IMWG criteria. Results Two hundred and seventy-five patients were included in this study; median age at T0 was 65 years (range 27-90). Fifty five percent of patients were males, 52% had IgG isotype, 29% had ISS stage III disease, and 29% had high-risk cytogenetics at diagnosis. Median interval from diagnosis of MM to T0 was 50.1 months (mo) (range 2.5-230.1). Patients received a median of 4 lines of treatment (1-16) prior to the CD38 MoAB-containing regimen; 72% underwent prior autologous transplant. Daratumumab-refractory patients formed a majority (256, 93.1%) of this cohort. Most of the patients were refractory to lenalidomide (77%), pomalidomide (65%), bortezomib (68%), and carfilzomib (47%). Seventy patients (25.5%) were "penta-refractory" and 148 (53.8%) were "triple-refractory and quad-refractory". Median follow-up from T0 for survivors was 10.6 mo (range 1.9-42.3 mo). The median overall survival (OS) from T0 for the entire cohort was 8.6 mo (95% C.I. 7.2-9.9); OS for the groups based on refractoriness to prior treatments are shown (Figure). Two hundred and forty-nine patients (90.5%) received at least one line of treatment after T0, (median 2, range 1-10). The response rates and depth of responses to each line of treatment post T0 are shown (Table). Among patients who received ≥ 1 subsequent treatment, the median PFS and OS from T0 were 3.4 (95% C.I. 2.8-4.0) mo and 9.3 (95% C.I. 8.1-10.6) mo, respectively; the median OS for the 26 patients who received no further treatment was only 1.3 (95% C.I. 0.6-1.9) mo. By multivariate analysis, penta-refractoriness (HR 2.4, p <0.001), high-risk cytogenetics (HR 1.5, p=0.01), elevated LDH (HR 2, p<0.001) and creatinine > 2 (HR 2.4, p=0.01) at the onset of CD38-based therapy predicted inferior OS. Conclusions Patients with MM who become refractory to CD38 MoAB are increasingly less responsive to subsequent therapies. While survival is particularly dismal for penta-refractory patients, the outcomes are poor even for patients who are not refractory to other mainstream MM agents. The MAMMOTH study defines a MM population in urgent need for new therapies, and provides benchmark OS, PFS and response data for subsequent investigational therapies in this setting. Disclosures Malek: Celgene: Consultancy, Speakers Bureau; Janssen: Consultancy, Speakers Bureau; Takeda: Consultancy, Speakers Bureau; Sanofi: Consultancy, Speakers Bureau; Amgen: Consultancy, Speakers Bureau. Paul:Bristol Myer Squibb: Other: Stock and pension plan (past employee). Neppalli:Amgen: Consultancy; Celgene: Consultancy. Liedtke:Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Prothena: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen/Onyx: Consultancy, Honoraria, Research Funding; BlueBirdBio: Research Funding; celgene: Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech/Roche: Research Funding; Caelum: Membership on an entity's Board of Directors or advisory committees. Hari:Amgen Inc.: Research Funding; Celgene: Consultancy, Honoraria, Research Funding; Spectrum: Consultancy, Research Funding; Kite Pharma: Consultancy, Honoraria; Bristol-Myers Squibb: Consultancy, Research Funding; Sanofi: Honoraria, Research Funding; Janssen: Honoraria; Takeda: Consultancy, Honoraria, Research Funding. Vij: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, Research Funding; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jansson: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: Honoraria, Membership on an entity's Board of Directors or advisory committees. Usmani:Abbvie, Amgen, Celgene, Genmab, Merck, MundiPharma, Janssen, Seattle Genetics: Consultancy; Amgen, BMS, Celgene, Janssen, Merck, Pharmacyclics,Sanofi, Seattle Genetics, Takeda: Research Funding. Kumar:Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Membership on an entity's Board of Directors or advisory committees, Research Funding; AbbVie: Membership on an entity's Board of Directors or advisory committees, Research Funding. Costa:Karyopharm: Research Funding; Sanofi: Honoraria; Janssen: Research Funding; BMS: Research Funding; Abbvie: Research Funding; Amgen: Honoraria, Research Funding; Celgene: Honoraria, Research Funding.

Abstract Background: Maintenance therapy post-autologous stem cell transplantation (ASCT) has shown to improve progression-free and overall survival in multiple myeloma (MM) and has largely become the standard of care. Consolidation therapy, a brief duration of more-intensive chemotherapy administered prior to maintenance, has been shown to further deepen responses and may improve long-term outcomes. Ixazomib, lenalidomide and dexamethasone (IRd) is an all oral regimen that has been shown to be active in newly diagnosed MM as well as relapsed disease. In this study, we are analyzing the safety and efficacy of IRd as consolidation therapy after ASCT (NCT02253316). Methods: Eligible patients, age 18-70 with newly diagnosed MM undergoing ASCT during first-line treatment, are being consented prior to ASCT. Approximately 4 months following ASCT, patients receive 4 cycles of consolidation therapy with IRd [ixazomib 4 mg on days 1, 8 and 15 of a 28-day cycle, lenalidomide 15 mg on days 1 through 21, and dexamethasone 40 mg on days 1, 8 and 15]. The primary end point is minimal residual disease (MRD) status. MRD is being assessed by ClonoSEQ where possible and by multi-color flow where not. Toxicity, IMWG response rate, PFS, and OS are secondary end points. One month after the last consolidation cycle, patients are randomized (1:1) to maintenance therapy with single-agent ixazomib (4 mg on days 1, 8 and 15) or lenalidomide (15 mg daily). In total, 240 patients will be enrolled on the trial. This presentation coincides with planned interim analysis 2 which included data from the consolidation phase only. Results: As of July 2018, 172 patients with NDMM have been enrolled from 10 centers within the US. The median age was 57 (range 28-70) and 67% were male. 76% were white, 10% African-American/Black, and 13% were another race. 39% were ISS Stage I, 30% were Stage II, and 20% were Stage III. All patients received proteasome inhibitors and/or IMIDs as front-line induction and melphalan as conditioning for ASCT. IRd consolidation started at a median of 110 days post-ASCT (range 80-138). IRd has been well tolerated. Only 4% (6/154) of patients have been unable to complete the 4 cycles of consolidation to date due to toxicity. Grade 3 hematologic toxicity has been uncommon; 4% neutropenia, 3% thrombocytopenia, and 2% anemia. There has been no grade 4 hematologic toxicity. Non-hematologic grade 3-4 toxicities have included: infection (8%), nausea/vomiting/diarrhea (3%), and transaminitis (1%). No grade 3-4 peripheral neuropathy has been reported. One case of grade 5 pneumonia was reported but was not considered related to study treatment. Following ASCT, the MRD-negative rate was 26% and this improved to 37% following consolidation. In the subset of patients with Clonoseq results available, the MRD negative rate improved from 19% to 27%. Clinical response rate improved similarly; prior to consolidation the VGPR or better rate was 76% including 39% CR/sCR. Following consolidation, the VGPR or better rate was 85% including 56% CR/sCR. 137 patients went on to receive maintenance with either ixazomib (n = 71) or lenalidomide (n = 66). At time of submission, the median follow-up from start of IRd is 14 months and 28 patients have relapsed/progressed and 6 have expired. An interim analysis is planned for 2019, representing the first comparison of ixazomib and lenalidomide maintenance. Conclusion: IRd consolidation following ASCT appears to be safe and effective. The all oral regimen is convenient for patients which greatly simplifies follow-up in the peri-transplant period. Study enrollment is scheduled to complete in Q1 of 2019. Disclosures Vij: Karyopharma: Honoraria, Membership on an entity's Board of Directors or advisory committees; Jazz Pharmaceuticals: 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, Research Funding; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Jansson: Honoraria, Membership on an entity's Board of Directors or advisory committees. Martin:Amgen: Research Funding; Sanofi: Research Funding; Roche: Consultancy. Deol:Kite Pharmaceuticals: Consultancy; Novartis: Consultancy. Kaufman:Janssen: Consultancy; Karyopharm: Other: data monitoring committee; BMS: Consultancy; Abbvie: Consultancy; Roche: Consultancy. Hofmeister:Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Adaptive biotechnologies: 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; Bristol-Myers Squibb: Research Funding. Gregory:Poseida Therapeutics, Inc.: Research Funding. Berdeja:Amgen: Research Funding; Celgene: Research Funding; Janssen: Research Funding; Takeda: Research Funding; Poseida Therapeutics, Inc.: Research Funding; Bristol-Myers Squibb: Research Funding; Bluebird: Research Funding; Genentech: Research Funding; Glenmark: Research Funding; Novartis: Research Funding; Teva: Research Funding; Sanofi: Research Funding. Chari:Pharmacyclics: Research Funding; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees; Array Biopharma: Research Funding; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnology: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Consultancy; The Binding Site: Consultancy.

Abstract Abstract 1024 Background: The MMRC is a non-profit, disease-focused consortium founded in 2004. Sixteen North American member institutions with expertise in multiple myeloma (MM) work collaboratively with the MMRC Inc. (Norwalk, CT) and numerous pharmaceutical partners to speed development of new treatment options to MM patients. In December 2007, MMRC Inc. implemented business solutions to address barriers to rapid activation of phase I-II trials and established benchmarks for initiating and conducting these studies. In December 2010, we reported significantly faster trial start up and accrual data from previous years1,2. Today, we update and expand on MMRC performance data and analysis of progress. Methods: Twenty-five (25) trials conducted within the Consortium from May 2006 to July 2011 had sufficient start up trial data for review. FPFD was defined as the time from the member institutions' receipt of the final protocol (FP) from the trial sponsor, to the time the first patient was dosed on the trial at any participating MMRC member institution. With respect to enrollment, pre-study enrollment commitment (EC) established between MMRC and the study sponsor was defined as the total number of subjects committed to receive at least one dose of study drug across all participating MMRC centers on a trial; baseline enrollment timeline (BET) was prospectively defined as the target time period to attain EC. Results: Mean time to FPFD in the recent group of trials (RG; n=18; Sept 08-Jul 11) held steady at 131 calendar days from receipt of FP as compared to 181 days for the early group of trials (EG; n=7; Jun06-Sept08) representing a 28% reduction in time to FPFD. More importantly, there was a 20% decrease in time to FPFD by all participating MMRC centers on any MMRC trial from 189 days in the RG compared to 236 days in the EG representing an important achievement especially in the Phase I/II arena. MMRC trial accrual data was available for 17/25 trials (2 EG trials were missing data and 6 RG trials continue enrolling). The pre-study mean MMRC EC was 44 subjects per trial (n=19 trials; 849 patients); the mean actual MMRC enrollment was 49 subjects per trial (n=19; 935 patients through July 11) representing a 10% over enrollment versus committed enrollment. A total of 17/19 evaluable trials (89%) met their EC; 12/19 trials met EC within BET (71%) of which 8/12 trials (67%) reached EC 34% faster than their BET (representing a mean reduction of 4.5 months). The overall pre-study mean BET for 19 trials was 13.6 months. MMRC's actual mean enrollment timeline was 12.8 months for the group of 17 evaluable trials representing improvement over the original BET by a mean of 10%. Discussion: MMRC's acceleration of clinical trials provides physicians and patients with rapid access to novel compounds; industry with data for important drug development decisions; and academic institutions with more trials of high scientific interest. Even so, our data uncovered opportunities for improvement. The submission time from receipt of the final protocol from the trial sponsor to Scientific Review Committee (SRC) took an average 30 calendar days across all trials. A reduction to half this time could make a difference to patients and therefore warrants further exploration. Conclusion: Today, drug development in multiple myeloma is fast-paced and highly competitive. MMRC's frequent review of trial metrics provides valuable insight to continually speed answers to physicians, patients and industry. Disclosures: Richardson: Multiple Myeloma Research Consortium: Annual grant in support Clinical Trial Project Management. Vij:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Lonial:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Siegel:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Jakubowiak:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Reece:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Jagannath:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Hofmeister:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Stewart:Multiple Myeloma Research Consortium: Annual Grant in support of clinical trial Project Management. Wolf:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Krishnan:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Zimmerman:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Kumar:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Roy:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Fay:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management. Anderson:Multiple Myeloma Research Consortium: Annual grant in support of clinical trial Project Management.

Abstract Background: Multiple myeloma (MM) is a hematologic cancer characterized by a diversity of genetic lesions-translocations, copy number alterations (CNAs), and single nucleotide variants (SNVs). The prognostic value of translocations and of CNAs has been well established. Determining the clinical significance of SNVs, which are recurrently mutated at much lower frequencies, and how this significance is impacted by translocations and CNAs requires additional, large-scale correlative studies. Such studies can be facilitated by cost-effective targeted sequencing approaches. Hence, we designed a single-platform targeted sequencing approach capable of detecting all three variant types. Methods: We designed oligonucleotide probes complementary to the coding regions of 467 genes and to the IgH and MYC loci, allowing a probe to closely match at most 5 regions within the genome. Genes were selected if they were expressed in an independent RNA-seq MM data set and harbored germline SNP-filtered variants that: (1) occurred with frequency >3%, (2) were clustered in hotspots, (3) occurred in recurrently mutated "cancer genes" (as annotated in COSMIC or MutSig), or (4) occurred in genes involved in DNA repair and/or B-cell biology. IgH and MYC tiling was unbiased (with respect to annotated features within the loci) and spanned from 50 kilobasepairs (kbps) upstream of both regions to 50 kbps downstream of IgH and 100 kbps downstream of MYC. Results: We performed targeted sequencing of 96 CD138-enriched samples derived from MM patients, as well as matched peripheral blood leukocyte normal controls. Sequencing depth (mean 107X) was commensurate with that of available exome sequencing data from these samples (mean 71X). Samples harbored a mean of 25 non-silent variants, including those in known MM-associated genes: NRAS (24%), KRAS (22%), FAM46C (17%), TP53 (10%), DIS3 (8%), and BRAF (3%). Variants detected by both platforms showed a strong correlation (r^2 = 0.8). The capture array detected activating, oncogenic variants in NRAS Q61K (n=3 patients) and KRAS G12C/D/R/V (n=5) that were not detected in exome data. Additionally, we found non-silent, capture-specific variants in MTOR (3%) and in two transcription-related genes that have been previously implicated in cancer: ZFHX4 (5%) and CHD3 (5%). To assess the potential role of deep subclonal variants and our ability to detect them, we performed additional sequencing (mean 565X) on six of the tumor/normal pairs. This revealed 14 manually-reviewed, non-silent variants that were not detected by the initial targeted sequencing. These had a mean variant allele frequency of 2.8% and included mutations in DNMT3A and FAM46C. At least one of these 14 variants occurred in five of the six re-sequenced samples. This highlights the importance of this additional depth, which will be used in future studies. Our approach successfully detected CNAs near expected frequencies, including hyperdiploidy (52%), del(13) (43%), and gain of 1q (35%). Similarly, it inferred IgH translocations at expected frequencies: t(4;14) (14%), t(6;14) (3%), t(11;14) (15%), and t(14;20) (1%). As expected, translocations occur predominantly within the IgH constant region, but also frequently 5' (i.e., telomeric) of the IGHM switch region, and occasionally within the V and D regions. We detected MYC -associated translocations, whose frequencies have been the subject of debate, at 10% (n=9 patients), with five involving IgH, three having both partners in or near MYC, and one having both types. Finally, our platform detected novel IgH translocations with partners near DERL3 (n=2), MYCN (n=1), and FLT3 (n=1). Additional evidence suggests that DERL3 and MYCN may be targets of IgH-induced overexpression: of 84 RNA-seq patient samples, six exhibited outlying expression of DERL3, including one sample in which we detected the translocation in corresponding DNA, and one exhibited outlying expression of MYCN. Conclusion: Our MM-specific targeted sequencing strategy is capable of detecting deeply subclonal SNVs, in addition to CNAs and IgH and MYC translocations. Though additional validation is required, particularly with respect to translocation detection, we anticipate that such technology will soon enable clinical testing on a single sequencing platform. Disclosures Vij: Celgene, Onyx, Takeda, Novartis, BMS, Sanofi, Janssen, Merck: Consultancy; Takeda, Onyx: Research Funding.

Abstract Abstract 3803 Background: The MMRC is a non-profit, disease-focused consortium founded in 2004 comprised of 13 North American centers with expertise in multiple myeloma (MM). The MMRC Inc. (Norwalk, CT), MMRC's member institutions, and several pharmaceutical partners work closely to speed early development of new treatment options for MM patients. In December 2007, MMRC headquarters staff implemented multiple project management (PM) business solutions to address trial barriers that delay activation of our phase I-II clinical trials and established trial metric benchmarks considered attainable at our member institutions. In November 2009, we reported initial data1 on trial activation: MMRC trials initiated between Sep08-Jul09 (n=5) demonstrated a 38% decrease in mean time to first patient dosed (FPFD), compared with the Early Group trials (EG) initiated before PM solutions (Jun06-Sept08; n=7 trials). These results also confirmed improvement over published metrics from Dilts et al 2,3. We present additional data on time to FPFD and now enrollment, to assess impact of the MMRC PM resources and processes on trial efficiency. Methods: Twenty-one (21) trials conducted within the MMRC from May 2006 to June 2010 had sufficient trial data for review. Data were collected by MMRC-funded project managers at the clinical centers using a web-based clinical trial management system (CTMS). FPFD was defined as the time from the member institutions' receipt of the final protocol (FP) from the trial sponsor, to the time the first patient was dosed on the trial at any participating MMRC member institution. With respect to enrollment, pre-study enrollment commitment (EC) established between MMRC and the study sponsor was defined as the total number of subjects committed to receive at least one dose of study drug across all participating MMRC centers on a trial; baseline enrollment timeline (BET) was prospectively defined as the target time period to attain EC. Results: Mean time to FPFD was 181 calendar days for the early group trials (EG, n=7) and 122 days for the recent group (RG) trials (n=14, Sep08 – Jun10), representing a 32% reduction of time to FPFD in the RG. Additionally, time from final protocol to first patient dosed at all MMRC centers on a trial decreased 18% from a mean of 7.7 months (EG) to 6.3 months (RG). With respect to MMRC trial enrollment, data was available for 16/21 trials (5 EG and 11 RG). 2 EG trials were missing data and 3 RG trials were still enrolling as of June 2010. The mean MMRC pre-study EC was 39 subjects per trial (n=16 trials; 626 enrollment target); the mean actual MMRC enrollment was 49 subjects per trial (n=16; 783 enrolled through Jun 29, 2010) representing a 25% increase in actual versus committed enrollment. Two trials did not meet MMRC EC: MMRC investigators discontinued their involvement in these trials at approximately 30% target EC due to trial complexity or low patient enrollment. 14/16 evaluable trials (88%) met their EC; 11/16 trials met EC within BET (69%) of which 8/16 trials (50%) reached EC 34% faster than their BET (representing a mean reduction of 4.5 months). The overall pre-study mean BET for 16 trials was 13.1 months. MMRC's actual mean enrollment timeline was 11.3 months for the group of 14 evaluable trials representing improvement over the original BET by a mean of 1.9 months (14%). We believe FP to FPFD is a more meaningful metric beyond that of first patient consented. Moreover, we believe that if all participating trial centers focus their efforts on dosing the first patient and within a targeted timeframe, it may improve our research efforts overall. Conclusion: Development of drugs in the clinical setting has become time and resource intensive. Activating and enrolling trials promptly is a priority for drug development. The MMRC's standardization of processes and support for site-based PM resources results in improved trial metrics. MMRC member centers met or exceeded pre-specified enrollment targets in 88% of the trials analyzed to date. Ongoing monitoring of trial conduct continues to reveal areas where increased focus is needed to realize further trial efficiencies. These trial metrics and measures to improve efficiency may be applied with similar expected benefit in all oncology disciplines. Disclosures: Wear: Multiple Myeloma Research Consortium (MMRC): Employment. Richardson:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC; Millennium: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Johnson & Johnson: Membership on an entity's Board of Directors or advisory committees. Revta:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Vij:Multiple Myeloma Research Consortium (MMRC): Research Funding; Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Fiala:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Lonial:Bristo-Myers Squibb: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene Corporation: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Millenium Pharmaceuticals Inc: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis Pharmaceuticals: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Onyx: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Francis:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Siegel:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC; Celgene: Speakers Bureau; Millennium: Speakers Bureau. Schramm:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Jakubowiak:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC, Research Funding; Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Honoraria, Speakers Bureau; Centocor Ortho-Biotech: Honoraria, Speakers Bureau; Exelixis: Honoraria, Speakers Bureau; Bristol-Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau. Harvey:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Reece:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC; Celgene: Honoraria, Research Funding; Ortho Biotech: Honoraria, Research Funding; Merck: Honoraria, Research Funding; Amgen: Honoraria, Research Funding; Facet: Research Funding; Otsuka: Honoraria, Research Funding. Gul:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Jagannath:Celgene: Honoraria; Millenium: Honoraria; Orthobiotec: Honoraria; Onyx Pharma: Honoraria; Merck: Honoraria; Proteolix: Honoraria; Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. La:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Hofmeister:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Jansak:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Stewart:Millennium: Consultancy; Celgene: Honoraria; Multiple Myeloma Research Consortium: Member Institution of the MMRC. Hagerty:Mayo Clinic: Employment; Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Wolf:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC; Celgene: Speakers Bureau; Millennium: Speakers Bureau; Novartis: Speakers Bureau; Orthobiotech: Speakers Bureau. Davis:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Krishnan:Celgene: Speakers Bureau; Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Duarte:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Zimmerman:Millennium, Celgene: Speakers Bureau. Cisneros:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Kumar:Celgene: Consultancy, Research Funding; Millennium: Research Funding; Merck: Consultancy, Research Funding; Novartis: Research Funding; Genzyme: Consultancy, Research Funding; Cephalon: Research Funding; Bayer: Research Funding; Multiple Myeloma Research Consortium: Member Institution of the MMRC. Birgin:Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC. Ott:Multiple Myeloma Research Consortium (MMRC): Employment. Tasca:Multiple Myeloma Research Consortium (MMRC): Employment. Kelley:Multiple Myeloma Research Consortium (MMRC): Employment. Anderson:Millennium: Consultancy; Multiple Myeloma Research Consortium (MMRC): Member Institution of the MMRC; Celgene: Consultancy; Novartis: Consultancy; Onyx: Consultancy; Merck: Consultancy; Bristol-Myers Squibb: Consultancy; Acetylon: Equity Ownership, Membership on an entity's Board of Directors or advisory committees. Giusti:Multiple Myeloma Research Consortium (MMRC): Employment.

Abstract Abstract 2965 Background: Alkylating agents have been the mainstay of multiple myeloma (MM) therapy for decades and despite introduction of several new therapies, it continues to play a significant role in its management as part of various drug combinations. While melphalan has been the most commonly used alkylator in MM, recent studies have suggested significant activity for bendamustine, a bifunctional alkylator. The combination of lenalidomide and melphalan has been associated with high response rates in relapse and newly diagnosed MM. Based on these promising results we designed a trial to evaluate the maximally tolerated dose of lenalidomide and bendamustine when used in combination as well as the efficacy of the combination in relapsed disease. Patients and Methods: Patients with relapsed MM and measurable disease were enrolled on this phase 1/2 trial provided they had not more than 4 prior lines of therapy for MM, had adequate performance status and organ and hematological function. Patients refractory to lenalidomide were allowed to enroll. The primary objectives were to (i) to determine the MTD of bendamustine and lenalidomide in combination with dexamethasone in subjects with relapsed MM (phase 1) and (ii) to evaluate the confirmed response rate of bendamustine in combination with lenalidomide and dexamethasone in patients with relapsed MM (phase 2). Bendamustine (B) was administered on days 1 and 2 of a 28-day cycle at doses of 50–100 mg/m2. Lenalidomide (R) was given days 1–21 at doses of 15–25 mg daily. Dexamethasone (D) was administered at 40 mg weekly. Dose escalation was done using a 3+3 design and MTD was defined as one dose level below that resulted in >=2 DLTS among 6 patients. The primary end point for this trial was the proportion of patients with confirmed hematologic response (sCR, CR, VGPR, or PR) over the first 6 cycles of treatment. Results: A total of 72 patients were accrued to this study from March 2010 to May 2012: 21 patients in phase 1 and 51 in phase 2. The 6 patients from the MTD dose level of phase 1 were also included in phase 2. The median age of all 72 patients was 62.1 (range, 40–86) and 57% were male. Majority (75%) of patients had previously been exposed to lenalidomide and 69% had prior exposure to bortezomib. Median # of prior therapies was 3 (range, 1–5) and 74% of patients had a prior autologous stem cell transplant. Patients have received a median of 4 cycles (range, 1–25), with 27 patients still continuing on active treatment. Disease progression led to study discontinuation in 22 (49%) and adverse events were the reason for discontinuation in 14 (31%). In phase I, two DLTs (Grade (Gr) 2 neuropathy and Gr 4 neutropenia) were seen at the highest dose level (100 mg/m2 B, 25 mg R), and the MTD was determined as 75 mg/m2 of B given days 1 and 2 and 25 mg of R days 1–21, along with D 40 mg weekly. Overall patients, 12/21 (57%) had a PR or better. In phase 2, 17 (40%) confirmed responses (>=PR) were seen among the 43 patients evaluable for response (received at least 6 cycles of treatment or have gone off study prior to 6 cycles); including 9 (21%) VGPR and 8 (19%) PR. An additional 5 patients had a minor response. Over all dose levels, a gr 3 or higher adverse event at least possibly attributed to the study was seen in 75% of patients. The most common toxicities were all hematological (thrombocytopenia and leukopenia), and most common non-hematological toxicity was infection. Prolonged time to recovery of blood counts was seen in a few patients, but majority of patients were able to tolerate the regimen with adequate dose reductions. Conclusion: The recommended dose of the combination for further studies is bendamustine at 75 mg/m2 days 1 and 2, lenalidomide 25 mg daily on days 1–21 and dexamethasone days 1, 8, 15, 22; with cycles repeated every 28 days. The regimen is well tolerated with hematological toxicity being the most common and manageable with dose reductions. The regimen is effective with high response rates and durable responses seen. Updated results with response rates and time to event analyses will be available for the entire cohort at the time of meeting. Disclosures: Kumar: Merck: Consultancy, Honoraria; Celgene: Research Funding; Millennium: Research Funding; Novartis: Research Funding; Cephalon: Research Funding; Genzyme: Research Funding. Krishnan:celgene: Consultancy, Speakers Bureau. Zimmerman:Celgene: Honoraria; Millennium: Honoraria; Novartis: Expert Testimony, Expert Testimony Other. Vij:Teva: Speakers Bureau; Celgene: Honoraria, Research Funding, Speakers Bureau; Millennium: Speakers Bureau; Onyx: Honoraria, Research Funding.

Abstract Introduction: IgM-secreting myeloma is rare, encompassing about 1% of all the myeloma cases. Given its rarity, the characteristics and survival of these patients have not been extensively studied. Therefore, we carried out a multicenter retrospective study in patients with IgM myeloma. Methods: The study protocol was reviewed and approved by the Institutional Review Board of each participating institution. Clinical data were gathered and included age, sex, hemoglobin, calcium, LDH, estimated glomerular filtration rate (GFR), presence of lytic bone lesions, International Staging System score, cytogenetic abnormalities, final outcome and overall survival (OS) time. OS was defined as the time in months from diagnosis to last follow-up or death. The Chi-square and the rank-sum tests were used to compare categorical and continuous variables, respectively. The Kaplan-Meier method was used to estimate OS and the log-rank waas used to compare groups. The Cox proportional-hazard regression method was used to fit univariate and multivariate survival models, reported as hazard ratio (HR) with 95% confidence intervals (CI). All reported p-values are two-sided, and were considered significant if less than 0.05. Results: A total of 159 patients with IgM myeloma from 20 centers from Europe, USA and Latin America were included in this analysis. Patients were diagnosed between 1996 and 2015. The median age at diagnosis was 65 years (range 37-86 years) with a male predominance (68%). The median serum IgM level was 2510 mg/dl (range 27-12,100 mg/dl) with 25% of patients having a serum IgM within normal limits but an IgM monoclonal spike detectable in serum electrophoresis. Hemoglobin levels <10 g/dl were seen in 49 patients (32%), serum calcium was elevated in 24 (16%), estimated GFR of 60 ml/min or less in 56 (37%), lytic lesions were detected in 86 (58%), and serum LDH was elevated in 28 (24%). ISS scores of 1, 2 and 3 were seen in 53 (36%), 63 (43%) and 31 (21%) of patients, respectively. Although immunohistochemistry and/or flow cytometry data were limited, CD20 expression was seen in 15/26 (58%) and cyclin D1 in 10/15 (67%) patients. The most common cytogenetic abnormalities were t(11;14) in 26/67 (39%), del13q in 25/76 (33%) and del17p in 6/76 (8%) patients. 149 patients (94%) received at least one line of systemic therapy for myeloma of which 13 (9%) received rituximab as part of initial therapy. After a median follow-up of 47 months, 74 patients (47%) have died. The median OS was 62 months (95% CI 51-79 months). Cause of death was known in 38 patients, and the most common was myeloma progression (74%). IN the univariate analysis, prognostic factors associated with a worse OS were age (HR 1.03, 95% CI 1.01-1.06; p=0.01) and ISS score (ISS 2: HR 1.43, 95% CI 0.83-2.48; p=0.2, and ISS 3: HR 3.03, 95% CI 1.54-5.98; p=0.001, using ISS 1 as reference group), while male sex was associated with a better OS (HR 0.56, 95% CI 0.34-0.90; p=0.02). Hemoglobin, calcium, estimated GFR and lytic lesions were not associated with OS. In the multivariate analysis, male sex was associated with a better OS (HR 0.57, 95% CI 0.35-0.95; p=0.03) and ISS with worse OS (ISS 2: HR 1.57, 95% CI 0.89-2.74; p=0.12, and ISS 3: HR 2.76, 95% CI 1.38-5.55; p=0.004, using ISS 1 as reference group). Conclusion: Patients with IgM myeloma apparently present with similar clinical characteristics as patients with non-IgM myeloma. Pathologically, CD20 and cyclin D1 expression is common. The most common cytogenetic abnormalities identified were t(11;14) and del13q. Survival does not appear shorter than non-IgM myeloma patients, and the ISS appears to have similar prognostic value. Disclosures Castillo: Millennium: Research Funding; Janssen: Honoraria; Otsuka: Consultancy; Biogen: Consultancy; Abbvie: Research Funding; Pharmacyclics: Honoraria. Ghobrial:Celgene: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Novartis: Honoraria; Takeda: Honoraria; Noxxon: Honoraria; Amgen: Honoraria. Hájek:Celgene: Consultancy, Research Funding; Amgen: Consultancy, Honoraria, Research Funding; Janssen: Honoraria; BMS: Honoraria; Takeda: Consultancy. Hungria:International Myeloma Foundation Latin America: Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy; Amgen: Consultancy; Roche: Consultancy; Bristol: Consultancy; Janssen: Consultancy, Speakers Bureau. Niesvizky:Celgene: Consultancy, Research Funding, Speakers Bureau; Takeda: Consultancy, Research Funding, Speakers Bureau; Onyx: Consultancy, Research Funding, Speakers Bureau. Reagan:Alexion: Honoraria; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees. Richardson:Celgene: Membership on an entity's Board of Directors or advisory committees. Spicka:Janssen Cilag: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria; BMS: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Millenium: Honoraria. Gertz:Celgene: Honoraria; Med Learning Group: Honoraria, Speakers Bureau; Research to Practice: Honoraria, Speakers Bureau; Alnylam Pharmaceuticals: Research Funding; Novartis: Research Funding; Prothena Therapeutics: Research Funding; Ionis: Research Funding; NCI Frederick: Honoraria; Sandoz Inc: Honoraria; GSK: Honoraria; Annexon Biosciences: Research Funding.

Abstract BACKGROUND: Azacitidine and decitabine are indicated for the first line treatment of intermediate and high risk MDS. About 40% to 47% of patients respond to 1st line hypomethylating agents. The median duration of response is 13 months. There are no effective therapies for patients who fail to respond to or progress on hypomethylating agents. A phase II trial of high dose lenalidomide (50mg/day) induction therapy followed by low dose (10mg/day) maintenance therapy in elderly patients with AML had demonstrated a high CR/CRi of 30%. CR was restricted to patients with presenting WBC counts <10000/µL, peripheral blast counts <1000/ µL and < 30%, many of whom could have been classified as having MDS rather than AML by FAB criteria. With the rationale that MDS and AML represent a continuum of disease, and the promising results in AML we aimed to assess the clinical activity of high dose lenalidomide by conducting a clinical trial of high dose Lenalidomide induction followed by low dose maintenance in patients with hypomethylating agent refractory MDS. METHODS: We conducted an open label, single arm, multi-center phase II trial of high dose lenalidomide induction (50mg/day for two 28 day cycles) followed by low dose lenalidomide maintenance therapy (10mg/day for 12 cycles) for patients with MDS (as defined by FAB criteria) refractory to hypomethylating agents. Patients who had failed to show CR, PR or HI (hematological improvement) after at least 6 cycles of azacytidine or decitabine or who had progressed on treatment were considered eligible. Patients were enrolled in a Simon's optimal two-stage design with an intended sample size of 43. The primary endpoint was proportion of confirmed responses (CR, PR or HI), as defined by international working group criteria, during the 14 cycles of treatment. RESULTS: 24 patients were enrolled in the first stage of the study. 16 patients completed at least one cycle of therapy and were considered evaluable for efficacy. Efficacy: Characteristics and outcomes of patients are detailed in Table 1. There were no complete or partial remissions. Marrow complete remission (MCR) was seen in 8/16 patients (50%). One of the 8 patients with a MCR had 5q- karyotype; 3/8 had trisomy 8 and one patient had a complex karyotype with monosomy 7. Median duration of MCR was 70 days (range 28-336 days). MCR lasted beyond the high dose induction period in 2 patients, one of whom had a 5q interstitial deletion (112 days) and one patient with trisomy 8 (336 days). Hematologic improvement (HI) was seen in 2/16 patients (12.5%) (Refer to table below). Toxicity: ≥grade 3 toxicities included pneumonia (12/24, 50%), sepsis (4/24, 17%), febrile neutropenia (8/24, 33%), rash (2/24, 8%), thromboembolic event (1/24), MI (1/24), new cancer -mammary analogue salivary carcinoma- (1/24). TABLE 1 Pt No: Age IPSS Prior cycles of 5-aza/ decitabine Cycles of Lenalidomide Reason off trial Best Response 1 69 1.5 2 4 Pancytopenia MCR 2 78 3 8 1 Death-Unrelated SD 3 73 2 7 1 Consent withdrawn SD 4 87 2 14 12 Progression MCR, HI-p&n 6 72 2 13 2 Thrombocytopenia MCR 7 69 2 13 1 PE SD 8 75 1 7 2 New Cancer MCR 9 74 1 4 3 Progression SD 10 75 2 0 2 Progression SD 11 72 1 13 3 Thrombocytopenia MCR 12 75 3 6 1 Progression PD 13 78 1 9 3 Gr3 Fatigue MCR 14 70 0 19 2 Progression MCR, HI-p 15 72 1 23 1 Progression PD 16 73 1 8 2 Gr 3 fatigue MCR CONCLUSIONS: High dose lenalidomide followed by standard dose maintenance in hypomethylating agent refractory MDS resulted in a marrow complete remission rate of 50% and hematological improvement rate of 12.5%. Future protocols should explore whether an extended schedule of intermittent dosing of high dose lenalidomide would allow for improved efficacy with acceptable toxicity. Disclosures Off Label Use: Lenalidomide is used in this study in patients with MDS both with and without deletion 5q.Use in patients without deletion 5q is off label use.. Tibes:Tetralogic Pharmaceuticals: Research Funding. Stockerl-Goldstein:Celgene: Speakers Bureau. Jacoby:Norvo Nordisk: Consultancy. Cashen:Celgene: Speakers Bureau. Vij:Onyx: Honoraria, Research Funding; Sanofi: Honoraria; Jannsen: Honoraria; Novartis: Honoraria; Millennium: Honoraria; Celgene: Honoraria, Research Funding.

e18061 Background: Despite a favorable genetic profile, African-Americans (AAs) with mm have poorer outcomes secondary to inferior treatment. NCI-CCs provide the highest-quality of care and attendance has been associated with better outcomes in many cancers. AAs have greater access to NCI-CCs proximally; however, they attend these facilities at lower rates than their white peers. The impact of attendance at NCI-CCs on mediating racial disparities in mm outcomes has not been reported on to date. Methods: We reviewed cases of mm the Surveillance, Epidemiology, and End Results (SEER)-Medicare linked database from 2000-2011 who were enrolled in Medicare Part A and B > 1 year prior to diagnosis, excluding cases enrolled prior to age 65 and those where mm diagnosis occurred post-mortem. Any center designated a NCI-clinical or -comprehensive center in 2002, 2005, or 2010 was considered a NCI-CC; attendance was defined as 2 or more claims on separate dates (MEDPAR and Outpatient files) from a NCI-CC in the 12 months following mm diagnosis. Logistic regression was performed to determine if race was associated with attendance, Cox regression to determine the association of attendance with survival. Results: 21,843 cases were analyzed; the median age was 77 years; 80% were white, 15% AA/Black. Overall NCI-CC attendance was low, only 11% of the population. Compared to white patients, black patients had a 13% decreased odds (aOR 0.87, 95% CI 0.75-0.99) of NCI-CC attendance after controlling for age, gender, socioeconomic status, geographic, and overall health variables. Attendance was associated with a 28% decrease risk for death (aHR 0.72, 95% CI 0.68-0.76), but had little impact on black-white outcome disparities. Black patients had a 9% increase in risk (aHR 1.09, 95% CI 1.04-1.13) after controlling for NCI-CC attendance. Conclusions: Black patients with mm have lower NCI-CC attendance. This may be related to referral bias and/or patient declining referral. NCI-CC attendance was associated with superior outcomes; however, controlling for attendance did not mediate black-white outcome disparities suggesting that racial treatment disparities pervade beyond access to NCI-CCs.

Abstract Multiple myeloma (MM) is twice as common in African Americans (AA) compared to European Americans (EA). The reported familial clustering and the elevated MM risk among first-degree relatives of cases implicate genetic susceptibility. Previous genome-wide association studies (GWAS) in EA have identified 16 novel risk loci. In this study, we tested the generalizability of the established risk alleles to AA and conducted a meta-GWAS analysis using two sets of AA to identify additional novel common MM risk variants. In the first study, we genotyped 1,305 incident AA MM cases from the African American Multiple Myeloma Study (AAMMS) using the Illumina HumanCore GWAS array and compared them to 7,078 AA controls from the African Ancestry Prostate Cancer Consortium (AAPC) and African Ancestry Breast Cancer Consortium (AABC) using the Illumina 1M-Duo. In the second study, 95 additional AAMMS cases and 435 AA MM cases from the University of Arkansas for Medical Sciences (UAMS) were genotyped using the Illumina MegaBead Chip and compared to 2,390 AA controls from the Multiethnic Cohort. The Haplotype Reference Consortium (HRC) was used to impute the overlapping typed SNPS from each GWAS case and control set together. Per-allele risk associations were tested for 8,715,278 overlapping genotyped and imputed variants with &gt;1% frequency and &gt;0.8 imputation score using unconditional logistic regression in both sets, and the combined effects were estimated using a fixed-effect meta-analysis. Of the 16 reported risk loci discovered in EA, directional consistency was present for 15 variants; eight of these replicated at nominal significance p&lt;0.05, with the most statistically significant variant being rs4487645 at 7p15.3 (OR=1.38, p=3.56×10-6). AA individuals with polygenic risk scores from these 16 variants (PRS) in the top 10% stratum had a 1.44-fold increased MM risk compared to those with a PRS in the 25th -75th percentiles. Additionally, we identified three suggestive novel loci located at 12q12, 9p24.3 and 9p13.1 at p&lt;1×10-6, with ORs ranging from 1.25-1.55, but none reached genome-wide significance. The variant at 9p24.3 is located in an intron in the KANK1 gene and a correlated SNP in EAs (r2=0.5) is strongly associated with gene expression in neoplastic plasma cells (unpublished, Weinhold and Morgan). Our study replicated most of the reported risk loci discovered among EA, demonstrated that a PRS constructed using the 16 reported risk alleles was associated with MM risk, and provides suggestive evidence for additional loci associated with MM risk in AAs. Citation Format: Zhaohui Du, Chi Song, Kristin Rand, Niels Weinhold, David Van Den Berg, Amie Hwang, Xin Sheng, Victor Hom, Sikander Ailawadhi, Ajay K. Nooka, Seema Singhal, Karen Pawlish, Edward S. Peters, Cathryn Bock, Ann Mohrbacher, Alexander Stram, Sonja I. Berndt, William Blot, John David Carpten, Antoinette Stroup, Andrew Olshan, Wei Zhang, African Ancestry Breast & Prostate Consortium, Stephen Chanock, Jayesh Mehta, Graham A. Colditz, Jeffrey Wolf, Thomas G. Martin, Michael Tomasson, Mark A. Fiala, Howard Terebelo, Nalini Janakiraman, Laurence Kolonel, Loic LeMarchand, Elad Ziv, Daniel Stram, Ravi Vij, Leon Bernal-Mizrachi, Gareth J. Morgan, Jeffrey A. Zonder, Carol Ann Huff, Sagar Lonial, Robert Z. Orlowski, David V. Conti, Christopher A. Haiman, Wendy Cozen. A meta-analysis of genome-wide association studies of multiple myeloma among African Americans [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 223.