Lakshman, Arjun

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: The introduction of novel therapeutics has led to improved outcomes in patients with multiple myeloma (MM). MM and its precursor lesion smoldering multiple myeloma (SMM) have traditionally been associated with increased mortality despite treatment. We aimed to assess the impact of a diagnosis of SMM and MM compared to the general population in the context of established prognostic factors. Methods: We studied the overall survival of 1697 patients with smoldering multiple myeloma (SMM, n = 582) and multiple myeloma (MM, n = 1115) diagnosed at Mayo Clinic between 01/2005 and 12/2015. Expected survival accounting for age and sex was calculated using the United States general population (US) as the reference group. Observed and expected overall survival was expressed as the standardized mortality ratio (SMR) of observed to expected deaths. Kaplan-Meier overall survival estimates were calculated and the log-rank test was used to compare overall survival in subgroups. The subgroups of interest were based on the International Staging System (ISS) and the presence of fluorescence in situ hybridization (FISH) high-risk cytogenetics: t(4;14), t(14;16), t(14;20), and del(17p). Proportional hazards regression models were used to assess the associations between the aforementioned prognostic factors and overall survival. P-values below 0.05 were considered statistically significant. Results: The median age at diagnosis in patients with SMM and MM was 65 (32 - 92) and 63 years (24 - 90), respectively. Two hundred forty-nine patients (57%) and 663 (60%) were male. The median follow-up in patients with SMM and MM was 4.7 (0.1 - 11.0) and 2.6 years (0.2 - 9.5). The median overall survival for patients with SMM and MM was 9.0 (95% CI 8.4 - 9.7) and 7.9 years (6.4 - 8.7). With age- and sex-matched population controls as the reference, the SMRs in patients with SMM and MM were 2.6 (95% CI 2.2 - 3.0) and 4.6 (4.1 - 5.2). Among those MM patients with available data on ISS staging and FISH cytogenetics, 30% (236/780) had ISS III and 21% (188/878) had high-risk cytogenetics. Patients with MM (compared to SMM) experienced worse overall survival (HR 1.5, 95% CI 1.2 - 1.8, p < 0.001, n = 1697). Patients with ISS I/II MM (compared to SMM) experienced similar survival (HR 1.0, 95% CI 0.8 - 1.3, p = 0.698, n = 1131). Patients with ISS III MM (compared to MM with high-risk cytogenetics) experienced similar survival (HR 1.3, 95% CI 0.9 - 2.0, p = 0.128, n = 329). Conclusions: Patients with SMM and MM in this cohort experienced excess mortality compared to the general population. In the absence of universal screening the true morbidity and mortality of patients with SMM and MM remains unknown and is likely overestimated in hospital-based cohorts. Overall survival in patients diagnosed with SMM and patients with ISS I/II MM receiving contemporary anti-myeloma therapy was clinically indistinguishable. Patients treated for ISS III MM experienced overall survival similar to patients with cytogenetic high-risk disease. MM remains associated with excess mortality, the magnitude of which varies considerably based on the presence of additional tumor and host factors. The outcomes with modern therapy among the ISS I/II patients highlight the potential for improving outcomes of SMM by early intervention, especially for the higher risk patients. Figure. Figure. Disclosures Lacy: Celgene: Research Funding. Gertz:Medscape: Consultancy; Alnylam: Honoraria; janssen: Consultancy; spectrum: Consultancy, Honoraria; Ionis: Honoraria; annexon: Consultancy; celgene: Consultancy; Teva: Consultancy; Prothena: Honoraria; Apellis: Consultancy; Abbvie: Consultancy; Physicians Education Resource: Consultancy; Amgen: Consultancy; Research to Practice: Consultancy. Dispenzieri:Celgene, Takeda, Prothena, Jannsen, Pfizer, Alnylam, GSK: Research Funding. Russell:Vyriad: Equity Ownership. Kapoor:Takeda: Research Funding; Celgene: Research Funding. Kumar:Roche: Research Funding; AbbVie: 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; AbbVie: 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; KITE: 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; Janssen: 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; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Membership on an entity's Board of Directors or advisory committees; Merck: Membership on an entity's Board of Directors or advisory committees, Research Funding.

Abstract The high-risk abnormality del(17p) can be detected by fluorescence in situ hybridization on malignant plasma cells (PCs) and has an adverse prognostic impact in patients with multiple myeloma (MM). Patients with del(17p) have reduced overall survival (OS). Patients who acquire del(17p) later during the disease course are not well described. The disease characteristics at diagnosis predicting for acquired del(17p) and its overall impact on patient survival is not known. We compared 76 patients with MM who were negative for del(17p) at diagnosis and acquired it later with 152 control MM patients who did not acquire del(17p) at a comparable time point. Patients acquired del(17p) at a median of 35.6 months (range, 4.6-116.1 months) from diagnosis of MM after a median of 2 lines of therapy (range, 1-10 lines of therapy). When compared with controls, patients with acquired del(17p) had shorter median progression-free survival (PFS) (30.1 vs 23.0 months; P = .032) and OS (106.1 vs 68.2 months; P &lt; .001) from diagnosis. After the detection of del(17p), the median PFS was 5.4 months and the median OS was 18.1 months. High lactate dehydrogenase level (odds ratio [OR], 3.69; 95% confidence interval [CI], 1.11-12.24) and presence of t(4;14) (OR, 2.66; 95% CI, 1.09-6.48) or any high-risk translocation (OR, 2.23; 95% CI, 1.00-4.95) at diagnosis predicted acquisition of del(17p). High PC proliferative rate predicted shorter OS from detection of del(17p) (hazard ratio, 2.28; 95% CI, 1.31-3.96; P = .004). Our study shows that acquisition of del(17p) is an important molecular event associated with reduction in OS in MM. Certain baseline factors may predict acquisition of del(17p). This needs validation in prospective data sets.

Abstract The plasma cell proliferative index (PCPI), determined by a slide technique or by flow cytometry, detects cells in the S phase of the cell cycle and is a useful prognostic tool in patients with plasma cell disorders such as multiple myeloma and amyloidosis. We conducted a retrospective review analyzing the prognostic effect of PCPI in 306 patients with smoldering multiple myeloma (SMM). Seventy-nine (26%) patients had an elevated PCPI (&gt;0.5). An elevated PCPI predicted an inferior time to progression (median, 3.0 vs 7.1 years for those with a low PCPI; P = .0004). Within 24 months, the progression rate was significantly higher for patients with an elevated PCPI (49% vs. 20%; P &lt; .0001). PCPI is a valuable tool in risk stratifying patients with SMM and identifies patients with earlier progression who may benefit from closer follow-up and consideration of early intervention trials.

8038 Background: Daratumumab-based Combination Therapies (DCT) with bortezomib (V)/ lenalidomide (R)/ pomalidomide (P) and dexamethasone (d) showed exceptional activity in RRMM in trials. Experience outside of trials since the approval of Daratumumab (D) in 2015 is limited. Methods: RRMM pts seen at Mayo Clinic, MN from 12/2015 -12/2016 were reviewed. Pts who received ≥ 1cycle of DCT were included. Time-to-event analyses were done from date of starting DCT. Common terminology criteria for adverse events v4.0 were used to grade toxicities. Results: Of 130 pts, 59% were males and median age at DCT initiation was 67 (43-93) years, ECOG performance score was ≥2 in 29%. Pts were classified as mSMART high (22%), intermediate (22%) or standard (56%) risk. Median time from diagnosis to initiation of DCT was 51.3 (5-156) months (m), and median number of prior therapies was 4 (1-14). 14% of pts were refractory to prior D monotherapy. Fifty-three (41%), 34 (26%) and 25 (19%) received DPd, DRd and DVd respectively. Eighteen (14%) pts received ‘other’ DCT. Median time to first response (≥ PR) was 3.1 m (95% CI 2.1-4.6). Overall response rate was 46%, [CR-2%, VGPR-18%, PR-26%]. Minimal response was seen in 17%, with clinical benefit rate of 62%. Median estimated follow up from initiation of DCT was 5.5 m (CI 4.2-6.1). The median duration of response was 6.1 m [CI 5.1- not reached (NR)]. Median progression free survival (PFS) was 5.5 m (CI 4.1-7.8) and median time to next therapy (TTNT) was 5.9 m (CI 4.6-9.4). Median PFS for DPd, DRd, DVd and other DCTs were 4.6 (CI 2.7-NR), 7.8 (CI 5-NR), 3.9 (CI 2.1-NR) and 3.9 (CI 2.8-8.2) m, respectively (p = 0.3). Median PFS for quadruple refractory (n = 28) MM was 2.8 m (CI 2.2-5.3) vs 5.9 m (CI 4.9-NR) for the rest (p < 0.01). Median overall survival (OS) from DCT was NR (CI 11.4-NR). Grade 3 or higher hematological toxicities were seen in 42% of pts. Other toxicities included infections (37%), fatigue (31%), infusion reactions (16%) and diarrhea (10%). Conclusions: DCT are effective in RRMM, but the PFS remains short particularly in quadruple refractory pts, reflecting the challenges encountered in managing heavily-pretreated, and often less fit patients, in routine practice.

8014 Background: t(11;14) is a standard risk cytogenetic marker in MM. Methods: We reviewed 366 patients with MM who had t(11;14) by FISH and 732 age and period-matched controls without t(11;14), seen at our institution from 2004 to 2014 and outcomes were analyzed using time to first progression or death (PFS1) and overall survival (OS). Results: For the t(11;14) group at diagnosis, the median age was 63.7 yr (range, 22.1-95.4) with 64.5% of patients being male. Eighty nine (24.3%) patients were above 70 yr of age at diagnosis. 33.8%, 40.3% and 25.9% patients belonged to ISS 1, II and III stages respectively. 13% patients had elevated LDH. Monosomy 17 or del 17p were identified in 10.6% patients. The median follow up period was 56.9 months (m) (95% CI: 54.6-62.2) and 209 (57.1%) patients were alive at last follow-up. Among patients receiving proteasome inhibitor (PI)-based, immunomodulator (IMiD)-based, PI+IMiD based or other agent based induction therapy, 71.2%, 70.3%, 90.4% and 37.5% patients respectively attained ≥PR as best response to induction (p < 0.01). During their course, 223 (60.9%) patients underwent stem cell transplant. Median PFS1 and OS were 23.1 (CI: 20.8-27.9) and 78.6 (CI: 66.7-105.9) m respectively. Among the controls, high risk cytogenetics (HRC) was present in 142 (19.4%), and the median OS was 83.8 m (CI: 70.8-97.0) being comparable to t(11;14) group (p = 0.8). For all 1098 patients, using a Cox-proportional hazards model with age > 70 years, induction therapy (novel agent-based vs others), cytogenetics [HRC vs t(11;14) without HRC vs no HRC or t(11;14)], and ISS stage III vs II/I as predictors, age > 70 years [HR-2.2 (CI: 1.8-2.8) and p < 0.01], ISS III vs ISS II/I [HR-1.4 (CI: 1.1-1.8) and p < 0.01] and HRC [HR of 2.1 (CI: 1.6-2.8) vs no HRC or t(11;14) (p < 0.01) and 1.9 (CI = 1.4-2.6) for t(11;14) without HRC (p < 0.01)were associated with reduced OS. The risk for reduced OS did not differ between t(11;14) without HRC, and those without t(11;14) or HRC [HR-1.1 (CI: 0.9-1.4), p = 0.4]. Conclusions: Our study characterizes the outcomes of a large cohort of MM patients with t(11;14) at diagnosis. Advanced age, HRC and advanced stage at diagnosis were associated with worse OS in our cohort. t(11;14) MM without HRC does not differ in outcome compared to non-t(11;14) MM without HRC.

AbstractExperience with intensive chemotherapy for relapsed/refractory multiple myeloma (RRMM) using VDT PACE regimen and its modifications (VDT PACE‐like regimens: VPLRs) outside TOTAL THERAPY trials is limited. We analyzed the outcomes of 141 patients with RRMM who received VPLRs at our center between 2006 and 2017 in an intent‐to‐treat analysis. Median age was 59.7 years and 66.7% of patients were male. A median of 2.2 years (range 0.02‐11.4) separated diagnosis of myeloma and inititation of VPLR. High‐risk cytogenetics were present in 52.4% patients. Patients received a median of 4 (range 1‐14) prior therapies, including stem cell transplant (SCT) in 66.7% patients. Ninety‐five (67.4%) patients received VDT PACE, 20 (14.2%) patients received VD PACE and 26 (18.4%) patients received other VPLRs. Patients received a median of 1 cycle (range 1‐9) of VPLR. We observed ≥ minimal response in 68.4%, ≥ partial response (PR) in 54.4% and ≥ very good PR in 10.3% patients. Median progression‐free survival was 3.1 months (95% CI, 1.9‐3.9) and median overall survival (OS) was 8.1 months (CI, 6.2‐9.9). One‐hundred and sixteen (82.3%) patients received some therapy after VPLR; 71 (61.2%) received systemic chemotherapy, while 45 (38.8%) underwent SCT. Median OS for those who received SCT after VPLR was 15.1 months (CI, 10.3‐20.8). Age ≥ 60 years (hazard ratio [HR] 2.3 [CI, 1.4‐3.7]; P = 0.0008) and R‐ISS III stage (HR‐ 2.4 [CI, 1.3‐4.0]; P = 0.003) predicted shorter OS in patients receiving VPLR. VPLRs are effective in heavily pre‐treated RRMM. In fit patients, SCT can be used to consolidate the response to VPLR.

AbstractOutside of clinical trials, experience with daratumumab‐based combination therapies (DCTs) using bortezomib (V)/lenalidomide (R)/pomalidomide (P), and dexamethasone (d) in relapsed/refractory multiple myeloma (RRMM) is limited. We reviewed the outcomes of 126 patients who received ≥ 1 cycle of any DCT. Median age at DCT initiation was 67 (range, 43‐93) years. High‐risk cytogenetics was present in 33% patients. Median number of prior therapies was 4 (range, 1‐14) and time to first DCT from diagnosis was 4.3 years (range, 0.4‐13.0). Seventeen (13%) patients were refractory to single agent daratumumab. Fifty‐two (41%), 34 (27%), 23 (18%), and 17 (14%) received DPd, DRd, DVd and “other” DCTs, respectively. Overall response rate was 47%. Median follow‐up was 5.5 months (95% CI, 4.2‐6.1). Median progression‐free survival (PFS) was 5.5 months (95% CI, 4.2‐7.8). Median overall survival was not reached (NR) with any regimen. Median PFS (months) was worst for penta‐refractory MM (n = 8) vs quadruple refractory MM (n = 18) and others (n = 100) (2.2 [95% CI, 1‐2.4] vs 3.1 [95% CI, 2.1‐NR] vs 5.9 [95% CI, 5.0‐NR]; P < .001); those who were refractory to ≥1 agents used in the DCT vs others (4.9 [95% CI, 3.1‐6.0] vs 8.2 [95% CI, 4.6‐NR]; P = .02); and those who received >2 prior therapies vs others (5.0 months [95% CI, 3.7‐5.9] vs NR [95% CI, NR‐NR]; P = .002). Non‐hematologic toxicities included infections (38%), fatigue (32%), and infusion reactions (18%). Grade 3 or higher hematological toxicities were seen in 41% of patients. DCTs are effective in RRMM. ORR and PFS in heavily pretreated patients are lower than those reported in clinical trials.