Stewart, A. Keith

Abstract Abstract 1845 Poster Board I-871 Background: Proteasome inhibition is an effective strategy for the treatment of multiple myeloma. In patients, proteasome inhibition has primarily been measured in peripheral blood samples (whole blood or mononuclear cells). However, it is unknown whether myeloma cells in the bone marrow (BM) are equally sensitive to proteasome inhibitors such as bortezomib (BTZ) and carfilzomib (CFZ). Aim: To measure proteasome inhibition in purified tumor cells from BM samples taken from patients enrolled in two ongoing Phase 2 trials of single agent CFZ in relapsed or refractory myeloma: PX-171-003 (003) and PX-171-004 (004). Methods: CFZ was administered as an IV bolus of 20 mg/m2 on Days 1, 2, 8, 9, 15 and 16 of a 28-day cycle on both trials. Bone marrow samples, from an optional sub-study of both trials, were taken during screening and Day 2 (post-treatment) and sorted into CD138+ and CD138− cells. Proteasome activity was measured by an enzymatic assay using a fluorogenic substrate (LLVY-AMC) for the chymotrypsin-like (CT-L) activity and an active site ELISA (ProCISE) to quantitate levels of the CT-L subunits of the constitutive proteasome (Beta5) and immunoproteasome (LMP7) and the immunoproteasome subunit MECL1. Results: Whole blood samples from patients treated with CFZ showed inhibition of CT-L activity of ∼80+, similar to values obtained in Phase 1 studies. A total of 10 CD138+ screening samples, 6 from 004 and 4 from 003, and 9 post-dose samples, 5 from 004 and 4 from 003, were analyzed for proteasome levels and activity. In addition, 15 CD138−screening samples, 7 from 004 and 8 from 003, and 9 post-dose samples, 5 from 004 and 4 from 003, were analyzed. When compared to the average base-line activity, CFZ treatment resulted in 88% CT-L inhibition in CD-138+tumor cells from 004 patients (P = 0.0212 by unpaired t-test) and 59% CT-L inhibition in CD-138+ tumor cells from 003 patients (P = 0.25). Baseline CT-L activity in CD138+ tumor cells was 3-fold higher in 004 than 003, which includes a more heavily pre-treated patient population with greater prior exposure to BTZ. Higher specific enzymatic activity was due to increased levels of both constitutive and immunoproteasomes in tumor cells, where immunoproteasomes account for >75% of total cellular proteasomes. No differences between trials were seen in baseline CT-L activity from non-tumor (CD138−) cells. Inhibition in CD138− cells was 84% (P = 0.0380 and 42% (P = 0.38) in 004 and 003, respectively. Using ProCISE, we measured inhibition of LMP7 (66%), beta5 (48%) and MECL1 (64%) in CD138+ tumor cells from 004 patients. Three patients from 004 and one from 003 had both a screening and post-dose tumor cell samples available for analysis. Inhibition of CT-L activity was >80% in two of the 3 patients on 004; the third patient showed no proteasome inhibition by ProCISE and was unavailable for analysis by CT-L. CT-L activity in the CD138+ tumor cells in the 003 patient was not inhibited, however, inhibition was seen in non-tumor cells. Conclusions: CFZ inhibits the proteasome activity of myeloma cells in the bone marrow of relapsed and refractory myeloma patients. The levels of inhibition were similar to those measured in whole blood samples, supporting the use of the blood-based assay as a surrogate marker for proteasome inhibition in tumor cells. CFZ treatment resulted in inhibition of both CT-L subunits as well as additional subunits of the immunoproteasome in tumor cells. Reduced baseline activity in the more heavily pretreated 003 patients may reflect reduced tumor-dependency on the proteasome and may be related to prior treatment with BTZ in these patients. More samples are needed in order to make correlations between levels of proteasome inhibition in bone marrow tumor cells and prior therapies or response. These observations support further evaluation of proteasome activity and the effects of this promising new agent in primary tumors cells from myeloma patients. Disclosures: Trudel: Celgene: Honoraria, Speakers Bureau; Ortho Biotech: Honoraria. Lee:Proteolix, Inc.: Employment. Kirk:Proteolix, Inc.: Employment. Lonial:Celgene: Consultancy; Millennium: Consultancy, Research Funding; BMS: Consultancy; Novartis: Consultancy; Gloucester: Research Funding. Wang:Proteolix, Inc.: Research Funding. Kukreti:Celgene: Honoraria. Stewart:Genzyme, Celgene, Millenium, Proteolix: Honoraria; Takeda, Millenium: Research Funding; Takeda-Millenium, Celgene, Novartis, Amgen: Consultancy. Jagannath:Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. McDonagh:Proteolix: Research Funding. Zonder:Celgene: Speakers Bureau; Pfizer: Consultancy; Seattle Genetics, Inc.: Research Funding; Amgen: Consultancy; Millennium: Research Funding. Bennett:Proteolix: Employment.

Abstract Abstract 1802 Poster Board I-828 Background Heterogeneity in multiple myeloma (MM) leads to disparate outcomes with a wide variation in overall survival (OS). Based upon the evidence predominantly gathered from newly diagnosed patients treated with standard chemotherapy and/or transplantation, the current Mayo (mSMART) prognostic model uses a combination of metaphase cytogenetics, fluorescence in-situ hybridization (FISH) and plasma cell labeling index (PCLI) for risk-stratification at diagnosis of MM. The objective of our study was to evaluate the significance of this stratification model in the era of novel therapies, and to assess the independent prognostic value of each of the components in the model. Methods Data were abstracted from a cohort of 1556 consecutive patients with MM who presented to our institution between January 1999 and March 2009 within ninety days of diagnosis of MM A total of three hundred and eighty six patients had been evaluated with conventional cytogenetics near diagnosis in addition to interphase FISH. Out of this cohort, three hundred and sixty six patients had availability of all the three tests, including the slide-based PCLI. High-risk MM was defined as presence of any one or more of the following: cytogenetics: hypodiploidy, monosomy of chromosome 13 or deletion 13q ; FISH: deletion of p53 (locus 17p13) or immunoglobulin heavy chain (IgH) translocations, t(4;14) (p16.3;q32) or t(14;16)(q32;q23); PCLI ≥3%. Survival estimates were created using the Kaplan-Meier method and compared by log-rank tests. The impact of each of the three tests was assessed by a multivariate (MV) analysis using Cox proportional hazards model. Results The median OS of the cohort of 366 patients was 65 months from presentation. One hundred and twelve (31%) patients were deemed high risk by any one or more of the three tests: Metaphase cytogenetics, FISH or PCLI (current mSMART definition of high-risk MM). The median OS of high risk patients was 52 months versus 71 months for standard-risk (P=0.007). We then studied the prognostic value of the three tests separately. Patients classified as high risk by FISH had a median OS of 35 months versus 65 months for the standard risk, HR= 2.3, P<0.001. Similarly, cytogenetics alone was also able to classify patients into high and standard risk with a comparable HR of 2.1 (P=0.008, median survival 37 vs. 64 months). In contrast, PCLI did not have a significant prognostic value (HR =1.41, P=0.32). This was confirmed on multivariate analysis in a model that included all 3 tests. FISH (HR=2.36, P=0.001) and cytogenetics (HR=1.99; P=0.017) emerged as independent determinants of prognosis in the multivariable analysis, while PCLI (HR=1.03, P=0.93) did not provide additional prognostic value. We then examined whether the prognostic value of FISH contributed additionally in patients classified into high and standard risk by conventional cytogenetics, and vice versa. Those classified as high risk by cytogenetics (n=44, 11 %), were further categorized into 2 groups by additional prognostic information obtained by FISH (median survival 18 vs. 52 months; P=0.005). Similarly, those classified as standard risk by cytogenetics (n=342, 89 %), were further categorized into 2 groups (median survival 52 vs. 71 months; P=0.017) by additional FISH-based stratification. Similarly, high-risk patients defined by FISH (n=65, 17 %) were further classified into 2 groups with significant difference in median OS (18 vs. 52 months, P=0.004), based on the presence or absence of high-risk features on cytogenetics. In contrast, no additional prognostic information was gained by cytogenetics in patients who were stratified as standard risk by FISH alone (n=321, 83%). Conclusion Our study validates high risk features defined by FISH and conventional cytogenetics in the mSMART risk stratification model among patients treated after the introduction of novel therapies. Either test identifies a high risk cohort with a hazard ratio of approximately 2 (median survival ∼37 versus ∼65 months). In patients known to have high risk disease by one of the two tests, knowledge of the other appears to add additional prognostic value. Disclosures Fonseca: Amgen, BMS, Celgene, Otsuka, Genzyme and Medtronic: Consultancy. Gertz:celgene, millennium: Honoraria. Dispenzieri:celgene: Research Funding. Kumar:celgene, genzyme, millennium, novartis, bayer: Research Funding; genzyme: Membership on an entity's Board of Directors or advisory committees.

Abstract Abstract 1827 Poster Board I-853 Background It is now well established that cytogenetic abnormalities can affect the responses to therapies in multiple myeloma (MM) patients. Bortezomib, used alone or in combination with other agents, has been shown to overcome the adverse impact of several common unfavorable cytogenetic features. More recently, responses with lenalidomide and dexamethasone have been reported in patients with some types of unfavorable cytogenetics. Carfilzomib (CFZ) is a novel proteasome inhibitor that has demonstrated single agent activity in relapsed and/or refractory MM patients. The objective of this analysis was to provide the first preliminary information on the influence of cytogenetics in patients (pts) with relapsed and/or refractory MM treated with CFZ. Methods We evaluated 79 pts treated on two single agent CFZ studies (PX-171-003 and PX-171-004) in relapsed and/or refractory myeloma in which metaphase cytogenetics and/or FISH analysis for del 13q, t(4:14), and t(14;16) chromosomal abnormalities were available. Metaphase cytogenetics was conducted for all pts in the analysis; fluorescence in situ hybridization (FISH) results were available for 28 of the 79 pts. Twenty-one pts with relapsed and refratory MM (PX-171-003) and 58 pts with relapsed or refractory MM (PX-171-004) received CFZ at 20 mg/m2 IV on days 1, 2, 8, 9, 15, and 16 in a 28-day cycle for up to 12 cycles. For this analysis, responders were defined as pts who achieved at least a Minor Response (MR) [MR + Partial Response (PR) + Very Good Partial Response (VGPR) + Complete Response (CR)] by IMWG and EBMT criteria. Results The median age of analysed pts was 63 yrs and 100% of pts were relapsed, with 70% refractory to their last therapy. Analysis of their histories demonstrated prior thalidomide treatment in 75% of pts, prior lenalidomide treatment in 57%, prior bortezomib treatment in 55%, and prior stem cell transplantation in 84%. The response rate (≥MR) for the entire group of patients was 40.5%. Twenty three of 79 pts had at least one of the abnormalities. The presence of del 13q, t(4;14), or t(14;16) did not significantly change the response rates, with 43.5% of pts with one or more abnormalities responding compared to 39.3% with none. The median time to progression (TTP) for all patients in this analysis was 203 days. The TTP for pts with one or more of the abnormalities was 195 days and was not significantly different from the TTP of 208 days for pts with none of the abnormalities (Figure; P > 0.05). Conclusion In this preliminary analysis, CFZ showed comparable activity in relapsed and relapsed/refractory MM with del 13q and/or t(4:14), and/or t(14;16) versus none of these abnormalities, with ≥MR in 43.5% vs. 39.3% of patients, and a TTP of 195 vs. 208 days, respectively. Updated efficacy data and TTP data will be presented at the meeting. Disclosures Jakubowiak: Millennium: 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; Centocor Ortho Biotech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Exelixis: 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. Wang:Proteolix, Inc.: Research Funding. Jagannath:Millennium: Honoraria, Membership on an entity's Board of Directors or advisory committees; Merck: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Siegel:Celgene: 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. Stewart:Takeda-Millenium, Celgene, Novartis, Amgen: Consultancy; Takeda, Millenium: Research Funding; Genzyme, Celgene, Millenium, Proteolix: Honoraria. Kukreti:Celgene: Honoraria. Lonial:Celgene: Consultancy; Millennium: Consultancy, Research Funding; BMS: Consultancy; Novartis: Consultancy; Gloucester: Research Funding. McDonagh:Proteolix: Research Funding. Vallone:Proteolix, Inc.: Employment. Kauffman:Proteolix, Inc.: Employment. Vij:Proteolix: Research Funding.

Background:Carfilzomib (CFZ) combined with dexamethasone is approved to treat patients (pts) with relapsed and/or refractory multiple myeloma (RRMM), with CFZ given once‐weekly at 70 mg/m2 (Kd70 QW) or twice‐weekly at 56 mg/m2 (Kd56 BIW). No randomized trials have directly compared Kd70 QW with Kd56 BIW.Aims:We performed a post hoc comparison between pts who received Kd56 BIW in the ENDEAVOR trial and pts who received Kd70 QW in the A.R.R.O.W. or CHAMPION‐1 trials.Methods:Data were analyzed from 3 trials of CFZ in RRMM: A.R.R.O.W. (240 pts in Kd70 QW arm; 2–3 prior therapies and refractory to most recent therapy), CHAMPION‐1 (104 pts received Kd70 QW; 1–3 prior therapies), and ENDEAVOR (464 pts in Kd56 BIW arm; 1–3 prior therapies). Pts who received Kd70 QW in A.R.R.O.W. and CHAMPION‐1 were pooled and compared with pts who received Kd56 BIW in ENDEAVOR. As study populations slightly varied among the 3 trials, an analysis of safety and efficacy was performed in a subgroup of pts who received 2–3 prior therapy lines and were not refractory to bortezomib (BTZ). Also, we performed regression analyses (controlling for age, ISS stage, BTZ and lenalidomide refractory status, and number of prior regimens) among all pts in the trials who received Kd70 QW or Kd56 BIW.Results:Among BTZ non‐refractory pts with 2–3 lines of prior therapy, median progression‐free survival (PFS) was 12.1 months (95% CI 8.4–14.3) for Kd70 QW (n = 146) and 14.5 months (95% CI 10.2–NE) for Kd56 BIW (n = 217), and the overall response rate (ORR) was 69.9% (95% CI 61.7–77.2) for Kd70 QW and 72.4% (95% CI 65.9–78.2) for Kd56 BIW. The rate of grade ≥3 adverse events (Kd70 QW vs Kd56 BIW) was 67.6% and 85.3%; among adverse events of interest, the grade ≥3 rate was 1.4% and 5.1% for cardiac failure, 3.4% and 6.0% for renal failure, and 5.5% and 15.7% for hypertension. Kd70 QW represents a convenient and well‐tolerated treatment modality for pts with RRMM. In a Cox proportional hazards model, the hazard ratio for PFS (Kd70 QW vs Kd56 BIW) was 0.91 (95% CI 0.69–1.19), and in a logistic regression model the odds ratio for ORR (Kd70 QW vs Kd56 BIW) was 1.12 (95% CI 0.74–1.69).Summary/Conclusion:This post hoc analysis suggests that once‐weekly Kd70 has a comparable benefit‐risk profile to twice‐weekly Kd56.© 2019 American Society of Clinical Oncology, Inc. Reused with permission. This abstract was accepted and previously presented at the 2019 ASCO Annual Meeting. All rights reserved.

Background:The treatment paradigm for multiple myeloma (MM) has evolved rapidly following new drug approvals and combinations. These improvements have the potential to improve outcomes for patients, but only if specialists in hematology/oncology (hem/oncs) have up‐to‐date knowledge on selection of treatments, prevention and management of adverse events (AEs), and comfort with emerging clinical trial data.Aims:We sought to determine if a curriculum of online continuing medical education (CME) activities could improve hem/onc knowledge and competence in treating patients with MM.MethodsThis analysis included hem/onc data from a MM curriculum spanning over 4 years, with 54 activities. For each year of the curriculum, an expert panel identified knowledge/competence gaps to be addressed through CME. Within the analysis, assessment questions were grouped into learning topics and the average for pre and post‐education was calculated for 2016‐2018 of the curriculum for each topic. The analysis elucidated the impact of the curriculum on narrowing gaps in knowledge/competence using a pre/post design. Statistical significance was assessed using a chi‐square statistic (P < .05 level).Results:As of December 2018, the curriculum had reached 33,699 US hem/onc learners and 2144 participated in the outcomes assessment. Treatment Selection: The curriculum significantly improved hem/onc knowledge/competence over time for selecting treatment for patients with relapsed/refractory (R/R) MM (pre/post: 2016, 41%/51%, P < .001; 2018, 48%/64%, P < .001). Managing AEs: The curriculum led to sustained knowledge gains for hem/oncs over time related to managing treatment‐related AEs in patients with MM (pre/post: 2016, 39%/53%, P < .001; 2018, 80%/84%, P = .427). Knowledge of Clinical Trial Data: Activities within the curriculum also significantly improved hem/onc knowledge of clinical trial data for consolidation and maintenance therapy (pre/post: 2016, 63%/76%, P < .001; 2017, 68%/74%, P < .05; 2018, 62%/76%, P < .001). Potential Patient Impact: The reach of Medscape Oncology CME has a large impact on how US hem/oncs treat patients with MM. Of all hem/onc specialists with MM diagnostic encounters, 64% are members of Medscape. Additionally, 70% of all high decile (deciles 7‐10) hem/onc specialists with MM diagnostic encounters are members of Medscape. Based on the number of learners for the curriculum and the average number of patient encounters, this education has the potential to impact 33,894 MM patient encounters.[IQVIA Data]Summary/Conclusion:This analysis shows that online CME, as part of a sustained educational curriculum, using various formats (video, text, panel discussion, case‐based) can significantly improve the knowledge and competence of hem/oncs in multiple areas related to MM. Statistically significant gains in knowledge and competence selecting treatment for R/R MM were seen even with the introduction of new clinical evidence in this area. The analysis also shows the potential impact on patients and the large reach that is achievable with online education. As new therapies and combinations of treatments continue to change practice, additional education is needed to aid hem/oncs in staying abreast of new data, managing AEs, and tailoring therapy selection for individual patients with MM.