Diels, Joris

Introduction: CARTITUDE-4 is a phase 3 randomized controlled trial (RCT) assessing the efficacy and safety of CARVYKTI (ciltacabtagene autoleucel; cilta-cel) versus pomalidomide, bortezomib and dexamethasone (PVd) or daratumumab, pomalidomide and dexamethasone (DPd) in patients with relapsed and refractory multiple myeloma (RRMM) with one to three prior line(s) of therapy that included an immunomodulatory agent (IMiD) and a proteasome inhibitor (PI), and who are refractory to lenalidomide. Based on the latest reported results from CARTITUDE-4, cilta-cel demonstrated superiority over PVd and DPd on progression-free survival (PFS), overall survival (OS) and response rates (overall response rate [ORR], very good partial response [VGPR] or better, and complete response [CR] or better [CR or better]). In 2023, an initial analysis was performed to compare the efficacy outcomes between all apheresed patients from the cilta-cel arm in CARTITUDE-4 vs doublet (Pd and Kd) and daratumumab-based triplet (DKd and DVd) therapy regimens in the same target population using available patient level data. Data from an updated prespecified data-cut of CARTITUDE-4 with median follow-up of 34 months became available, allowing for an updated assessment of the comparative efficacy, including OS, between cilta-cel and these treatment regimens. Methods: Individual patient data were collected from the CARTITUDE-4 (cilta-cel), CASTOR (DVd), CANDOR (DKd and Kd), and APOLLO (Pd) RCTs, from which patients who met CARTITUDE-4 eligibility criteria were identified. As no patients in the comparative trials had prior treatment with anti-CD38, patients with prior exposure to anti-CD38 therapies in the cilta-cel cohort were excluded. Key prognostic baseline covariates including refractory status, ISS stage, presence of extramedullary disease (EMD), and time to progression on prior line, were adjusted for using inverse probability of treatment weighting (IPTW), with average treatment effect in the treated weights. Differences in baseline characteristics were assessed using standardized mean differences. PFS, OS and response rates (ORR, ≥VGPR and ≥CR) were compared between cilta-cel versus the comparator regimens. Relative efficacy for PFS and OS was estimated with Hazard ratios (HRs) and 95% confidence intervals (CIs) using weighted Cox proportional hazards regression. Response endpoints were analyzed using weighted logistic regression estimating response rate ratios (RRs) and 95% CIs. Sensitivity analyses using alternative statistical approaches and including additional covariates were explored. Results: After the exclusion of 53 patients with prior exposure to an anti-CD38 therapy, 155 patients in the cilta-cel arm remained, and were compared to patients treated with DVd (n=44), DKd (n=98), Kd (n=46) and Pd (n=92) who met the CARTITUDE-4 inclusion criteria. Baseline covariates were well balanced across the cohorts after IPTW. Patients from the cilta-cel arm showed significant improvements in PFS versus all comparators, with adjusted HRs ranging from 0.21 vs DVd to 0.58 vs DKd (all p ≤0.01). Also, OS was significantly longer for cilta-cel versus all other regimens, with adjusted HRs ranging between 0.31 vs Pd to 0.55 vs DKd (all p ≤0.05). While comparative estimates for ORR and VGPR did not change versus the previously reported results, the relative benefit for cilta-cel versus other regimens further increased on deeper levels of response, with adjusted RR for ≥CR from 2.71 vs DKd to 31.47 vs Pd (all p≤0.001). Treatment with DKd consistently yielded the best results out of all comparator regimens but results were still significantly in favor of cilta-cel. Results of cilta-cel benefit were generally consistent across sensitivity analyses. Conclusions: Results from this updated analysis confirm the previously observed significant superiority of PFS and response outcomes of cilta-cel, whilst showing significant OS benefit compared to commonly used treatment regimens for this patient population. These findings provide valuable information to support cilta-cel as a highly effective treatment for RRMM patients who received 1-3 prior lines of therapy, including a PI and IMiD, and who are refractory to lenalidomide, particularly in countries where standard of care may be different from DPd/PVd.

Abstract Background: Patients with relapsed and refractory multiple myeloma (RRMM) who have triple class exposure to immunomodulatory drugs (IMiDs), proteasome inhibitors (PIs) and anti-CD38 monoclonal antibodies (MoABs) have a poor prognosis and high unmet medical need. Ciltacabtagene autoleucel (cilta-cel) is a chimeric antigen receptor T-cell therapy which may offer long-term disease control for these patients. CARTITUDE-1 is an open-label, single arm phase 1b/2 clinical trial conducted to characterize the safety and efficacy of cilta-cel in adult patients with triple-class exposed RRMM. Since CARTITUDE-1 is a single-arm study, adjusted comparisons to other currently available therapies can provide valuable information on relative efficacy and safety benefits of cilta-cel over current real-world clinical practice (RWCP). LocoMMotion is the first prospective study of RWCP efficacy and safety outcomes in triple-class exposed patients with RRMM. It was designed a priori to serve as an external control cohort for CARTITUDE-1, using aligned inclusion criteria and endpoint definitions, to enable robust, high quality indirect comparisons vs. cilta-cel. Objective: To compare patient outcomes of cilta-cel vs. RWCP, including overall response rate (ORR), complete response or better rate (≥CR rate), progression-free survival (PFS) as assessed by a review committee and overall survival (OS) in patients with triple-class exposed RRMM. Methods: Individual patient level data available from both CARTITUDE-1 (clinical cut-off February 2021) and LocoMMotion (clinical cut-off March 2021) were pooled to conduct the comparative analyses. Imbalances between both cohorts on key prognostic baseline characteristics, including refractory status, ISS stage, time to progression on prior line, number of prior lines, average duration of prior lines, age, creatinine clearance, ECOG PS and MM type were adjusted for using inverse probability weighting. Average treatment effect on the treated (ATT) weights derived from propensity scores estimated using multivariable logistic regression modeling were applied to the LocoMMotion patients to have the weighted RWCP cohort reflecting the CARTITUDE-1 patient population. Balance between the ATT weighted RWCP cohort versus the CARTITUDE-1 population was evaluated based on reduction of standardized mean differences and overlap of propensity score distributions. Weighted logistic and Cox proportional hazards regression were used to estimate the relative treatment effects for cilta-cel vs. RWCP on binary endpoints (Odds ratios (OR), transformed into Response-rate Ratios (RR) and time to event endpoints (Hazard ratios (HR)), respectively. The base case analyses included all enrolled (apheresed) patients from CARTITUDE-1, reflecting an intention to treat approach. Additional analyses were conducted including only patients who received cilta-cel infusion compared to an aligned population of LocoMMotion where patients that progressed or died within 52 days were excluded from the LocoMMotion cohort. Results: 113 patients were enrolled in CARTITUDE-1, of which 97 were infused with cilta-cel. 246 patients were enrolled in LocoMMotion receiving RWCP in Italy (24%), Germany (15%), France (14%), UK (11%), Spain (10%), USA (9%), Belgium (5%), Poland (5%), Netherlands (4%) and Russia (3%). Therapies within the RWCP cohort were diverse and >90 unique treatment regimens were used. The most frequent regimens were Kd (13.8%), PCd (12.6%) and Pd (11.0%). The weighted LocoMMotion population was well balanced with the CARTITUDE-1 cohort. Adjusted comparisons (Table 1) showed statistically significant improvements for cilta-cel vs. RWCP for ORR (RR=4.43), ≥CR (RR=568.92), PFS (HR=0.15) and OS (HR=0.38), all comparisons with p<0.001. All additional analyses were consistent with these findings (Table 1). Conclusions: Outcomes for patients with triple-class exposed RRMM treated with RWPC observed in LocoMMotion are poor, illustrating the high unmet medical need. Adjusted comparisons vs. CARTITUDE-1 demonstrate significantly improved ORR, ≥CR, PFS and OS for cilta-cel compared to a diverse set of RWCP. These findings highlight cilta-cel's potential as a highly effective treatment option for patients with triple-class exposed RRMM. Figure 1 Figure 1. Disclosures Mateos: Regeneron: Honoraria, Membership on an entity's Board of Directors or advisory committees; GSK: Honoraria; Sea-Gen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Adaptive Biotechnologies: Honoraria, Membership on an entity's Board of Directors or advisory committees; Celgene - Bristol Myers Squibb: Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria; Takeda: Honoraria, Membership on an entity's Board of Directors or advisory committees; AbbVie: Honoraria; Amgen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Honoraria, Membership on an entity's Board of Directors or advisory committees; Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees; Sanofi: Honoraria, Membership on an entity's Board of Directors or advisory committees; Bluebird bio: Honoraria; Pfizer: Honoraria, Membership on an entity's Board of Directors or advisory committees. Weisel: GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive Biotechnologies: 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, Research Funding; Bristol Myers Squibb: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees; Roche: Honoraria; Oncopeptides: 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; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy; Novartis: Honoraria; Pfizer: Honoraria. Martin: Sanofi: Research Funding; Oncopeptides: Consultancy; Janssen: Research Funding; GlaxoSmithKline: Consultancy; Amgen: Research Funding. Berdeja: Celularity, CRISPR Therapeutics: Research Funding; Abbvie, Acetylon, Amgen: Research Funding; Bluebird bio, BMS, Celgene, CRISPR Therapeutics, Janssen, Kite Pharma, Legend Biotech, SecuraBio, Takeda: Consultancy; EMD Sorono, Genentech: Research Funding; GSK, Ichnos Sciences, Incyte: Research Funding; Lilly, Novartis: Research Funding; Poseida, Sanofi, Teva: Research Funding. Jakubowiak: Karyopharm: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Gracell: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees. Stewart: Oncopeptides: Honoraria; Janssen: Honoraria; GSK: Honoraria; BMS: Honoraria; Amgen: Honoraria; Skyline diagnostics: Consultancy; Genomcs England: Membership on an entity's Board of Directors or advisory committees; Tempus Inc.: Current holder of individual stocks in a privately-held company, Membership on an entity's Board of Directors or advisory committees; PikSci Inc.: Current holder of individual stocks in a privately-held company, Patents & Royalties; Sanofi Aventis: Honoraria. Jagannath: Legend Biotech: Consultancy; Bristol Myers Squibb: Consultancy; Karyopharm Therapeutics: Consultancy; Janssen Pharmaceuticals: Consultancy; Takeda: Consultancy; Sanofi: Consultancy. Lin: Novartis: Consultancy; Bluebird Bio: Consultancy, Research Funding; Legend: Consultancy; Sorrento: Consultancy; Juno: Consultancy; Takeda: Research Funding; Celgene: Consultancy, Research Funding; Gamida Cell: Consultancy; Vineti: Consultancy; Merck: Research Funding; Janssen: Consultancy, Research Funding; Kite, a Gilead Company: Consultancy, Research Funding. Diels: Janssen: Current Employment. Ghilotti: Janssen-Cilag SpA, Cologno Monzese, Italy: Current Employment. Perualila: Janssen: Current Employment. Cabrieto: Janssen: Current Employment. Haefliger: Janssen-Cilag AG: Ended employment in the past 24 months; Cilag GmbH International: Current Employment. Erler-Yates: Janssen: Current Employment. Hague: Janssen: Current Employment, Current equity holder in publicly-traded company. Jackson: Janssen: Current Employment; Memorial Sloan Kettering Cancer Center: Consultancy. Strulev: Janssen Pharmaceutica NV: Current Employment. Nesheiwat: Legend Biotech USA: Current Employment. Pacaud: Legend Biotech: Current Employment. Moreau: Janssen: Honoraria; Celgene BMS: Honoraria; Amgen: Honoraria; Sanofi: Honoraria; Abbvie: Honoraria; Oncopeptides: Honoraria. Einsele: Janssen, Celgene/BMS, Amgen, GSK, Sanofi: Consultancy, Honoraria, Research Funding.

Abstract Introduction. Efficacy and safety of daratumumab monotherapy (DARA mono) in relapsed/refractory multiple myeloma (rrMM) has been shown in the single-arm phase I/II trial GEN501 and the single-arm phase II trial SIRIUS (1, 2). Since then, several indirect treatment comparisons of DARA mono versus comparator therapies have been published showing consistent results with an overall survival benefit for DARA mono (3, 4, 5, 6). This analysis compares efficacy and for the first time also safety of DARA mono data versus an international historic control group, adjusting for differences in patient populations based on individual patient level data (IPD). Methods. IPD from the SIRIUS trial and from the International Myeloma Foundation (IMF)-cohort (7), a retrospective, multicenter cohort, were compared using a multivariate Cox proportional hazards model, on the endpoints of efficacy (overall survival (OS)) and safety (discontinuation due to adverse events (DISCONAE)). The IMF-cohort included patients with rrMM who received at least three prior lines of therapy, were refractory to both an immunomodulator (IMiD) and a proteasome inhibitor (PI), and were exposed to an alkylating agent. An inclusion criterion for the historic control group in this analysis was treatment with EU approved regimens. Baseline covariates adjusted for in the regression model included age, gender, prior lines of therapy, albumin, beta-2 microglobulin, prior exposure to pomalidomide and carfilzomib, and PI/IMiD refractory status. Several sensitivity analyses were run, including multiple imputation of missing values. Results. Data from 106 patients treated with DARA mono (16 mg/kg) were available from SIRIUS; 258 patients from the IMF chart review fulfilled the inclusion criteria; most frequent treatment regimens contained pomalidomide plus dexamethasone (PomDex) (n=172), bortezomib (n=31), carfilzomib (n=21), cyclophosphamide (n=14) and lenalidomide (n=9). The adjusted HR for OS was 0.41 [0.25, 0.69], p<0.001, and 0.23 [0.05, 1.00], p=0.050 for DISCONAE, in favor of daratumumab. Results were consistent across a range of sensitivity analyses and were similar when restricting the comparison to DARA vs. PomDex, with HR=0.35 [0.19, 0.64], p<0.001 for OS and 0.20 [0.03, 1.54], p=0.123 for DISCONAE. Conclusions. This comparison using real-world data of rrMM patients suggests improved efficacy and safety for DARA mono compared to approved therapy regimens used in clinical practice, including PomDex. References. Lokhorst, H. M., Plesner, T., Laubach, J. P., Nahi, H., Gimsing, P., Hansson, M., et al. Targeting CD38 With Daratumumab Monotherapy in Multiple Myeloma. The New England Journal of Medicine. 2015. Lonial S, Weiss BM, Usmani SZ, Singhal S, Chari A, Bahlis NJ, et al. Daratumumab Monotherapy in Patients with Treatment-Refractory Multiple Myeloma (SIRIUS): An Open-Label, Randomised, Phase 2 Trial. The Lancet. 2016. Usmani S, Ahmadi T, Ng Y, Lam A, Desai A, Potluri R, Mehra M. Analysis of Real-World Data on Overall Survival in Multiple Myeloma Patients With ≥3 Prior Lines of Therapy Including a Proteasome Inhibitor (PI) and an Immunomodulatory Drug (IMiD), or Double Refractory to a PI and an IMiD. The Oncologist. 2016. Van Sanden S, Ito T, Diels J, Vogel M, Belch A, Oriol A. Comparative Efficacy of Daratumumab Monotherapy and Pomalidomide Plus Low-Dose Dexamethasone in the Treatment of Multiple Myeloma: A Matching Adjusted Indirect Comparison. The Oncologist. 2017. Usmani SZ, Diels J, Ito T, Mehra M, Khan I, Lam A. Daratumumab monotherapy compared with real-world historical control data in heavily pretreated patients with highly refractory multiple myeloma: An adjusted treatment comparison. American Journal of Heamtology. 2017. Jelínek T, Maisnar V, Pour L, Špička I, Minařík J, Gregora E, et al. Adjusted comparison of daratumumab monotherapy versus real-world historical control data from the Czech Republic in heavily pretreated and highly refractory multiple myeloma patients. Current Medical Research an Opinion. 2017. Kumar SK, Dimopoulos MA, Kastritis E, Terpos E, Nahi H, Goldschmidt H, et al. Natural history of relapsed myeloma, refractory to immunomodulatory drugs and proteasome inhibitors: a multicenter IMWG study. Leukemia. 2017. Disclosures Demmer: Janssen: Employment. Huschens:Janssen: Employment. Potthoff:Janssen: Employment. Tomeczkowski:Janssen: Employment. Englisch:Janssen: Employment. Thilakarathne:Janssen: Employment. Diels:Janssen: Employment. Kumar:AbbVie: 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; AbbVie: 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; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche: Research Funding; KITE: 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; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Novartis: Research Funding; Takeda: 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; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding. Durie:Celgene: Consultancy; Amgen: Consultancy; Takeda: Consultancy; Janssen: Consultancy. Eisele:Janssen: Employment.

Abstract Introduction In 2 large phase 3 trials of patients (pts) with relapsed or refractory (R/R) CLL/SLL, single-agent ibrutinib (ibr) was superior to ofatumumab (ofa) (RESONATE; Byrd. NEJM 2013) and ibr + BR was superior to placebo + BR (HELIOS; Chanan-Khan. ASCO 2015). Both studies evaluated ibr in different pt populations with different relevant comparators (eg, ofa in pts who had relapsed following prior anti-CD20-based chemoimmunotherapy [CIT] and/or with del17p, and BR in pts eligible for CIT). In the absence of head-to-head evaluations of single-agent ibr vs BR or single-agent ibr vs ibr + BR, indirect comparisons can be used for hypothesis testing by potentially providing insights on the relative efficacy of treatments. As such, an indirect comparative analysis of data from RESONATE and HELIOS was performed. Recognizing biases inherent in cross-trial comparisons, including lack of randomization across trials and consequent differences in distributions of important confounding variables (eg, pt characteristics, prognostic factors), we used pt-level data from both studies to risk adjust for confounders using accepted multivariate statistical approaches. Methods In RESONATE, pts received 420 mg oral ibr daily until disease progression or unacceptable toxicity or intravenous ofa for up to 24 weeks. The primary end point was IRC-assessed PFS, with secondary end points of OS and ORR. In HELIOS, pts received BR (≤ 6 cycles) with either 420 mg oral ibr daily or placebo until disease progression or unacceptable toxicity. Pts with del17p were excluded. The primary end point was IRC-assessed PFS, with secondary end points of ORR and OS. Per protocol amendment in both studies, pts in comparator arms could switch to ibr upon IRC-confirmed progression. The current exploratory analysis was based on the latest available data from each trial (median time on study: RESONATE, 19 months; HELIOS, 17 months) using investigator assessments, but excluding del17p pts from RESONATE. Analyses were performed using data from both the overall CLL/SLL population and only the CLL pts. Separate multivariate Cox proportional hazards models were constructed for PFS and OS, including treatment and clinically relevant prognostic variables as covariates (age, gender, Rai staging, ECOG score, del11q status, refractory status, number of prior lines of therapy, bulky disease, IgVH status). Adjusted HRs and 95% CIs are presented vs single-agent ibr, along with predicted survival curves derived from the multivariate Cox regressions. Results RESONATE and HELIOS enrolled populations with notable differences making naïve comparison flawed. Because HELIOS enrolled only CIT-eligible pts, the trial included younger pts who had received fewer lines of therapy, as well as lower proportions of pts with purine analog refractory disease, del11q, or Rai stage 4 disease. These factors have been previously reported to influence outcomes in pts with R/R CLL/SLL and thus were included as covariates in the statistical models. Other baseline factors (gender, ECOG score, bulky disease, and IgVH status) were not notably different between the trials, but were found to impact PFS and OS and thus were included as additional covariates. In the overall CLL/SLL population, PFS and OS were comparable for single-agent ibr vs ibr + BR, and were significantly improved for single-agent ibr vs BR (Figure 1). Results for only the CLL pts were similar to those shown in Figure 1 for both PFS (ibr + BR vs single-agent ibr: 1.03 [0.61-1.75], p = 0.9042; BR vs single-agent ibr: 7.52 [4.72-11.99], p < 0.0001; single-agent ibr reduced the risk of progression/death by 87% vs BR) and OS (ibr + BR vs single-agent ibr: 1.20 [0.59-2.43], p = 0.6197; BR vs single-agent ibr: 2.24 [1.14-4.40], p = 0.0197; single-agent ibr reduced the risk of death by 55% vs BR). Conclusions The adjusted indirect comparisons reported here suggest superiority of single-agent ibr over BR for PFS and OS in patients with R/R CLL/SLL. The comparisons also suggest that the addition of BR to ibr did not improve PFS or OS compared with single-agent ibr. However, as median PFS has not been reached for either ibr arm, it is too early to draw firm conclusions. Longer follow-up in the ibr arms of these studies will be required to give an indication of whether CIT adds any benefit to ibrutinib for PFS and OS. Overall, these findings provide support for single-agent ibr as an appropriate choice for all pts with previously treated CLL/SLL. Disclosures Hillmen: Roche Pharmaceuticals: Honoraria, Research Funding; Janssen: Consultancy, Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Gilead: Honoraria, Research Funding; AbbVie: Honoraria, Research Funding; Celgene: Research Funding; Pharmacyclics LLC, an AbbVie Company: Honoraria, Research Funding. Fraser:Janssen: Honoraria, Research Funding, Speakers Bureau; Hoffman LaRoche: Consultancy, Honoraria; Celgene: Honoraria, Research Funding. Jones:Acerta Pharma BV: Research Funding. Rule:Roche: Consultancy, Other: Travel reimbursement; J&J: Consultancy, Other: Travel reimbursement, Research Funding; Celgene: Consultancy, Other: Travel reimbursement; Gilead: Research Funding. Dilhuydy:Roche: Honoraria, Other: Travel reimbursement; Janssen: Honoraria, Other: Travel reimbursement; Mundipharma: Honoraria. Jaeger:Janssen: Honoraria, Membership on an entity's Board of Directors or advisory committees. Cymbalista:Karyopharm: Honoraria; Roche: Honoraria; Gilead: Honoraria; Janssen: Honoraria, Research Funding. Sun:Janssen/J&J: Employment, Equity Ownership. Ninomoto:Pharmacyclics LLC, an AbbVie Company: Employment. Mahler:Janssen: Employment, Other: Travel reimbursement. Cheng:Pharmacyclics LLC, an AbbVie Company: Employment. Diels:Janssen: Employment. Clow:Pharmacyclics LLC, an AbbVie Company: Employment. Salman:Janssen/J&J: Employment, Equity Ownership. James:Pharmacyclics LLC, an AbbVie Company: Employment. Howes:Janssen/J&J: Employment, Equity Ownership.

Abstract Objective: To fully contextualize the benefit of novel agents such as daratumumab (DARA) monotherapy for the treatment of patients with heavily pre-treated and highly refractory multiple myeloma (MM), it is critical to understand the real-world outcomes of this patient population on current standard of care (SOC) therapies. The objective of this study was to perform adjusted comparisons to determine the comparative effectiveness of DARA monotherapy versus real-world SOC therapies. Methods: Data for patients treated with DARA 16 mg/kg monotherapy were available from clinical trials MMY2002 (n=106) and GEN501 (n=42), while patients treated with SOC therapies were derived from the International Myeloma Foundation (IMF) chart review of patients with MM who had ≥3 prior lines of therapy and were double refractory to a proteasome inhibitor (PI) and an immunomodulatory drug (IMiD) (n=543) (Kumar et al., ASH 2016; submitted). The pooled DARA studies demonstrated a median overall survival (OS) of 20.1 months versus 13.0 months for SOC based on the IMF cohort (Usmani et al., Blood 2016; Kumar et al., ASH 2016; submitted). The relative treatment effect of DARA versus SOC was estimated using two adjusted comparison methodologies, propensity score matching (PSM) and multivariate Cox regression analyses. Both methodologies utilized individual patient data to compare OS. Modeled covariates for the PSM were age, gender, prior lines of therapy, albumin, and refractory status to bortezomib (BOR), carfilzomib (CAR), lenalidomide (LEN), and pomalidomide (POM). PSM was performed using caliper matching with a caliper width 25% of the standard deviation of the logit-transformed propensity score, using sampling without replacement. For the regression analysis, the covariates included in the multivariate proportional hazards regression model were age, gender, prior lines of therapy, albumin, beta-2 microglobulin, prior exposure to POM and CAR, and PI/IMiD refractory status. Clustering of observations at the treatment-line level within patients was controlled for using the robust sandwich estimate for the covariance matrix, making confidence intervals (CIs) more conservative. For both PSM and regression, statistical significance testing was performed using a two-tailed p-value of <0.05, and all comparisons between treatment groups were reported with hazard ratios (HRs) and 95% CIs. Results: Prior to PSM, imbalances between the DARA and SOC groups were significant for prior lines of therapy and proportions of patients refractory to POM, CAR, BOR, and LEN. After PSM, the DARA and SOC groups were well balanced for all covariates included in propensity score calculations. After PSM, comparisons found significant improvement in favor of DARA relative to SOC for OS (HR=0.44 [95% CI 0.31-0.63]) (Figure 1). Regression analyses revealed consistent results. After adjustment for differences in all covariates included in regression between the DARA and SOC groups, results showed significant improvement in favor of DARA compared with SOC for OS (HR=0.43 [95% CI 0.32-0.59]) (Figure 2). Conclusions: Findings from both PSM and regression analyses were consistent and suggest that DARA is associated with significant gains in OS compared with SOC therapies for patients with heavily pre-treated and highly refractory MM. References: 1. Usmani SZ, Weiss BM, Plesner T, Bahlis NJ, Belch A et al. (2016) Clinical efficacy of daratumumab monotherapy in patients with heavily pretreated relapsed or refractory multiple myeloma. Blood 128 (1): 37-44. 2. Kumar SK, et al. (2016) Natural history of relapsed myeloma, refractory to immunomodulatory drugs and proteasome inhibitors: a multicenter IMWG study. The 58th Annual Meeting of the American Society of Hematology: submitted. Disclosures Kumar: Celgene: Consultancy, Research Funding; Noxxon: Consultancy, Honoraria; Janssen: Research Funding; AbbVie: Research Funding; BMS: Consultancy; Amgen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Sanofi: Consultancy, Research Funding; Skyline: Consultancy, Honoraria. Durie:Amgen: Consultancy; Takeda: Consultancy; Janssen: Consultancy. Su:Janssen: Research Funding. Diels:Johnson & Johnson: Employment, Equity Ownership. Hutton:Essai Canada: Consultancy; Cornerstone Research Group: Consultancy; Janssen: Research Funding. Lam:Janssen: Employment. Tetsuro:Johnson & Johnson: Equity Ownership; Janssen: Employment.