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T-cell redirection therapy using chimeric antigen receptor (CAR) T cells and bispecific antibodies (BiAbs) has shown promising efficacy in heavily pretreated patients with relapsed/refractory multiple myeloma (RRMM), leading to the approval of 2 CAR T-cell products and numerous BiAb trials. Data on the outcomes after relapse following BiAbs are urgently required to develop strategies for sequencing salvage therapies. We identified 58 patients progressing after a BiAb trial at Mount Sinai Hospital. Progression-free survival (PFS) to the first salvage (PFS1), second salvage therapy (PFS2), and overall survival (OS) were estimated using the Kaplan-Meier method. The median age of the patients was 67 years, and 78% had high-risk cytogenetics. They had a median of 6 prior therapy lines, 89% were triple-class refractory, and 44% were penta-drug refractory. After the BiAb trial, patients were followed for a median of 30.5 months and received a median of 2 additional salvage therapies (range, 1-9). The most common first salvage was T-cell redirection in 19 patients (10 BiAb and 9 CAR T cells). Ten patients underwent T-cell redirection as a second salvage treatment. T-cell redirection therapy as first or second salvage was feasible and associated with a median PFS1 of 28.9 months, PFS2 of 30.9 months, and an OS of 62% at 2 years. The sequential use of different T-cell redirection therapies is possible and may lead to deep and durable responses following the relapse after BiAb therapy in RRMM.

Objective To evaluate the association between pre-hospitalization antiplatelet medication use and COVID-19 disease severity. Design Retrospective cohort study. Setting Inpatient units at The Mount Sinai Hospital. Patients Adults age ≥18 admitted between March 1, 2020 and April 9, 2020 with confirmed COVID-19 infection with at least 28 days follow-up. Measurements We captured baseline demographic, pre-hospitalization antiplatelet medication use, and clinical encounter data for all patients who met inclusion criteria. The primary endpoint was peak score on a 6-point modified ordinal scale (MOS), which is based on World Health Organization blueprint R&S groups, used to grade severity of illness through clinical outcomes of interest. Scores indicate the following: 1 – COVID-19 infection not requiring hospitalization, 2 – requiring hospitalization but not supplemental oxygen, 3 – hospitalization requiring supplemental oxygen, 4 – hospitalization requiring high-flow nasal cannula (HFNC) or non-invasive positive pressure ventilation (NIPPV), 5 – hospitalization requiring intubation or extracorporeal membrane oxygenation (ECMO), 6 – death. Multivariable adjusted partial proportional odds model (PPOM) was performed to examine the association between pre-hospitalization antiplatelet medication use and likelihood of each MOS score. Main Results Of 762 people admitted with COVID-19, 239 (31.4%) used antiplatelet medications pre-hospitalization while 523 (68.6%) did not. Antiplatelet users were older and had more co-morbidities at baseline. Before adjusting for covariates, patients who used antiplatelet medications pre-hospitalization were more likely than non-users to have peak MOS score 6 (death, OR 1.75, 95% CI 1.21–2.52), peak MOS score ≥5 (intubation/ECMO or death, OR 1.4, 95% CI 1.00–1.98) and peak MOS score ≥4 (HFNC, NIPPV, intubation/ECMO or death, OR 1.40, 95% CI 1.01–1.94). On multivariable adjusted PPOM analysis controlling for 13 covariates, there were no longer any significant differences in peak MOS scores between users and non-users. Conclusions After adjusting for covariates, pre-hospital antiplatelet use was not associated with COVID-19 severity in hospitalized patients.

T-cell redirection therapy with chimeric antigen receptor (CAR)-T cells and bispecific antibodies (BiAbs) has shown promising efficacy in heavily pretreated relapsed/refractory multiple myeloma (RRMM) patients, leading to the approval of two CAR-T cell products and numerous BiAb trials. Data regarding outcomes after relapse following BiAbs are urgently needed to develop strategies for sequencing salvage therapies. We identified fifty-eight patients progressing after a BiAb trial at the Mount Sinai Hospital. Progression-free survival (PFS) to first- (PFS1) and second salvage therapy (PFS2), and overall survival (OS) were estimated using the Kaplan-Meier method. Patients had a median age of 67 years and 78% had high-risk cytogenetics. They had a median of 6 prior therapy lines, 89% were triple-class refractory and 44% were penta-drug refractory. After the BiAb trial, patients were followed for a median of 30.5 months and received a median of two additional salvage therapies (range: 1-9). The most common first salvage was T-cell redirection in nineteen patients (ten BiAb and nine CAR-T). Ten patients received T-cell redirection as second salvage. T-cell redirection therapy as first or second salvage was feasible and associated with a median PFS1 of 28.9 months and PFS2 of 30.9 months and an OS of 62% at 2 years. Sequential use of different T-cell redirection therapies is possible and can lead to deep and durable responses following relapse after BiAb therapy in RRMM.

Filanesib is a first‐in‐class kinesin spindle protein inhibitor which demonstrated safety and encouraging activity in combination with bortezomib and dexamethasone in relapsed/refractory multiple myeloma in a preliminary analysis of dose‐escalation phase results. This multicenter study included first a dose‐escalation phase to determine maximum tolerated dose of two schedules of filanesib, bortezomib, and dexamethasone and a subsequent dose‐expansion phase using the maximum tolerated doses. In the dose‐expansion phase, 28 patients were evaluable for safety and efficacy. The most common grade ≥3 adverse events were neutropenia (21%) and anemia (18%), which were noncumulative and reversible, and hypertension (18%). The overall response rate was 43% with median duration of response not yet reached (range, 2.8–23.7+ months) with median follow‐up of 6.3 months. A post hoc analysis incorporated 29 dose‐escalation phase patients who received therapeutic filanesib doses, with an overall response rate of 39% and median duration of response of 18.0 months among the 57 total patients with median progression‐free survival of 8.5 months. Notably, the PFS of high risk patients was comparable at 8.5 months, driven by the patients with 1q21 gain, characterized by increased MCL‐1 expression, with a PFS of 9.1 months versus 3.5 months for the remainder of high risk patients. Patients with t(11;14) also had an encouraging PFS of 15.0 months. The combination of filanesib, bortezomib, and dexamethasone continues to show safety and encouraging activity in relapsed/refractory multiple myeloma, particularly in those patients with 1q21 gain and t(11;14)., We report on the final analysis of the phase 1 trial of filanesib, bortezomib, and dexamethasone in relapsed/refractory multiple myeloma. Among patients receiving therapeutic doses of the study drugs, overall response rate was 39% with median duration of response of 14.1 months and median progression‐free survival of 8.0 months. The combination continues to show safety and encouraging activity in this population, particularly in those patients with 1q21 gain and t(11;14).

Background Previous studies have found that Black patients with multiple myeloma undergo autologous stem-cell transplantation (ASCT) less frequently than their white counterparts, although the factors leading to decreased access and utilization have not been fully elucidated. Patients and Methods To identify whether racial differences in transplantation timing played a role in these disparities, we retrospectively analyzed 410 Black and white patients who received their first transplant at The Mount Sinai Hospital between 2011 and 2016 (260 white and 150 Black patients). We compared the time from initial diagnosis to stem-cell collection and the time from collection to transplantation between the 2 races while controlling for age, socioeconomic status, and functional status. Results Between Blacks and whites, time from diagnosis to collection was higher in Black patients (median 238, vs. 195 days, respectively, P = .051). Functional status, socioeconomic status, and age were also significantly associated with time to collection, and after controlling for these covariates, the effect of race was not significant (P = .0625). Conversely, time from collection to transplantation was increased in white patients compared to Black. Conclusion Increased time from diagnosis to stem-cell collection for Black patients was driven in part by socioeconomic status and baseline functional status.

Nocardial infections have been rare after allogeneic hematopoietic stem cell transplantation (HSCT). We report 10 recent cases of late-onset nocardiosis (median time of onset of 508 days after transplantation) primarily in patients on high doses of corticosteroids for graft-versus-host disease. All 10 patients had pulmonary infection caused by Nocardia species susceptible to trimethoprim-sulfamethoxazole (TMP-SMX). At time of diagnosis 8 of 10 patients were not receiving TMP-SMX for prophylaxis of Pneumocystis jiroveci pneumonia (PJP; 7 on atovaquone, 1 on i.v. pentamidine). After the initiation of atovaquone prophylaxis for PJP in place of TMP-SMX for many UCLA allogeneic HSCT patients in 2012, 9 cases of nocardiosis occurred in 411 patients (2.2%) over the next 6 years (2012 to 2017) compared with only 1 case in 575 patients (0.17%) during the previous 12 years (2000 to 2011). Although there were no deaths directly related to nocardial infection treated primarily with TMP-SMX, overall mortality in this group of patients was 40%. Based on this experience, the use of atovaquone for PJP prophylaxis in place of TMP-SMX may be associated with an increased risk for previously rare nocardial infections after allogeneic HSCT.

Background: Novel treatment approaches including chimeric antigen receptor (CAR) T therapy and bispecific antibodies (Abs) have shown remarkable efficacy in highly pretreated multiple myeloma (MM) patients. With recent approval of BCMA-targeted CAR T in MM, and other agents in development, CAR T is poised to become more widely used in relapsed/refractory disease (RRMM). However, the prognosis, clinical outcome, and treatment approach to RRMM patients presenting with relapsed disease after CAR T are unknown. Methods: Demographics, disease characteristics and post-study outcomes were collected retrospectively in patients who relapsed after BCMA-targeted CAR T therapy at a single academic institution (Mount Sinai Hospital, NY). We identified 74 patients who previously enrolled on 1 of 6 clinical trials. At the data cutoff (July 2021), 4 patients died on trial and were not evaluable, whereas 31 patients had left the trial due to disease progression (PD) and were included. Five patients had received CAR T reinfusion after initial PD, in which case date of PD after reinfusion was considered the start of post-CAR T evaluation. This retrospective study was approved by the institutional review board (GCO#:11-1433). Survival analyses and follow-up duration were calculated by (reverse) Kaplan-Meier analysis. Results: At time of PD after CAR T, the 31 patients had a median age of 61 years (range 35-75) and 19 (61%) were male. Median time from diagnosis was 74 months (range 22-282). Of these 26 patients (84%) had high-risk cytogenetics on FISH [t(4;14), t(14;16), t(14;20), loss of TP53 or 1q21 gain]. Patients were highly pretreated with a median of 5 prior lines (range 1-18). 28 patients (90%) had received prior autologous stem cell transplant. Patients were refractory to various treatments: thalidomide (6% refractory), lenalidomide (74%), pomalidomide (84%), bortezomib (61%), carfilzomib (87%), ixazomib (23%), CD38-mAb (97%), alkylating agents (54%), venetoclax (19%) and selinexor (19%). Most (84%) were triple-class refractory. Fifteen patients (48%) had received DCEP and 4 (13%) had received prior treatment with non-BCMA-targeted bispecific Ab. Upon CAR T relapse, 12 patients (39%) progressed with new/increased extramedullary disease. Information on additional MM treatment was available for 28 patients (90%); 1 patient was treated with cytarabine for MDS, 1 received no treatment, and 1 was lost to follow-up. Median time from relapse to first subsequent treatment was 30 days (range 0-201). Patients received a median of 2 additional treatment lines (range 0-8). The most common initial treatment after CAR T relapse was chemotherapy with (V)DCEP or VD-PACE (10/28, 36%). Stem cell boost with prior chemotherapy was part of the initial approach in 5 patients (18%) and was performed in 12 patients at any time after CAR T relapse (43%). Five patients (18%) were treated with bispecific Ab immediately after CAR T and 12 (43%) received bispecific Ab therapy at any point after CAR T. Selinexor-based regimens were used in 3 (11%) patients immediately after and in 10 (36%) at any point after CAR T relapse. Best response to initial treatment varied widely with 46% ORR (7 CR, 5 VGPR, 1 PR, 7 SD, 8). Median time to progression was 105 days (95% CI: 78-204) for the initial treatment after CAR T. Across various treatment lines after relapse, 33 occurrences of durable response (>120 days, range 128-555) were noted, of which 8 involving stem cell transplant, 8 involving bispecific Abs (alone or in combination with approved anti-MM agents), 5 involving selinexor-based treatments, 3 with venetoclax and 3 involving a MEK inhibitor. Median PFS of patients transitioning to bispecific Ab therapy immediately after CAR T was not yet reached. At time of analysis, 16 patients (52%) were alive and median overall survival after relapse on CAR T was 15.0 months (455 days, 95% CI: 422-NE) with a median follow-up of 501 days. Conclusion: RRMM patients relapsing after T cell engager therapy are a challenging population. Studying the prognosis of these patients including response to subsequent therapy will provide important clinical insights, especially as CAR T moves to an earlier treatment setting. Even though, due to selection, our cohort might be biased towards subjects with early CAR T failure, we show that novel agents, including bispecific Abs can cause durable responses in post-CAR T relapse. Updated results will be presented at the meeting. Figure 1 Figure 1. Disclosures Richard: Karyopharm, Janssen: Honoraria. Richter: Oncopeptides: Consultancy; X4 Pharmaceuticals: Consultancy; Sanofi: Consultancy; Antengene: Consultancy; Karyopharm: Consultancy; BMS: Consultancy; Janssen: Consultancy; Celgene: Consultancy; Adaptive Biotechnologies: Speakers Bureau; Celgene: Speakers Bureau; Janssen: Speakers Bureau; Adaptive Biotechnologies: Consultancy; Secura Bio: Consultancy; Astra Zeneca: Consultancy. Chari: Oncopeptides: Consultancy, Membership on an entity's Board of Directors or advisory committees; Antengene: Consultancy, Membership on an entity's Board of Directors or advisory committees; Novartis: Consultancy, Research Funding; Genentech: Consultancy, Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Consultancy, Membership on an entity's Board of Directors or advisory committees; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Sanofi Genzyme: Consultancy, Membership on an entity's Board of Directors or advisory committees; Pharmacyclics: Research Funding; Amgen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS/Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Secura Bio: Consultancy, Membership on an entity's Board of Directors or advisory committees; Takeda: Consultancy, Research Funding; Millenium/Takeda: Consultancy, Research Funding; Shattuck Labs: Consultancy, Membership on an entity's Board of Directors or advisory committees; AbbVie: Consultancy, Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen Oncology: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding. Jagannath: Bristol Myers Squibb: Consultancy; Karyopharm Therapeutics: Consultancy; Janssen Pharmaceuticals: Consultancy; Takeda: Consultancy; Legend Biotech: Consultancy; Sanofi: Consultancy. Parekh: Foundation Medicine Inc: Consultancy; Amgen: Research Funding; PFIZER: Research Funding; CELGENE: Research Funding; Karyopharm Inv: Research Funding.

Background: Bispecific antibodies (BiAbs) are a novel off-the-shelf class of drugs currently being investigated in clinical trials for patients with relapsed/refractory multiple myeloma (RRMM) with promising efficacy in heavily pretreated patients. BiAbs simultaneously bind two antigens, thereby engaging CD3+ T cells with myeloma cells expressing specific antigens such as BCMA, GPRC5D, FcRH5 or CD38. However, the outcome of myeloma patients after relapse on BiAbs is unknown and effective approaches for salvage therapy are needed. Methods: Demographics, disease characteristics and post-clinical trial outcomes were collected retrospectively on RRMM patients who relapsed after BiAb therapy at the Tisch Cancer Institute (The Mount Sinai Hospital, New York). We identified a total of 116 patients who were enrolled on trials with BiAbs targeting either BCMA or GPRC5D. Of these, 69 patients were no longer enrolled on the trials due to disease progression (including 5 patients who died on the trial). Clinical data was collected up until July of 2021. This retrospective study was approved by the institutional review board (IRB) and follows the Declaration of Helsinki and International Conference on Harmonization Guidelines for Good Clinical Practice (IRB: GCO#: 11-1433). Survival and response duration were calculated by Kaplan-Meier estimation. Results: The 64 RRMM patients had a median age of 58.5 years (range: 46-82) at time of disease progression following BiAbs therapy, and 48% were male. Median time from diagnosis to initiation of BiAbs therapy was 5 years (range: 1.6-16.3) and patients had a median follow-up of 24.9 months from time of relapse from BiAb therapy. Fifty patients (78%) had high-risk cytogenetics, including gain1q21, del17p, t(4;14), t(14;16) and t(14;20). Most patients were highly pretreated with a median of 7 prior lines (range: 3-17) and 54 patients (84%) had received an autologous stem cell transplant (ASCT) prior to receiving BiAbs. Three patients were treated with chimeric antigen receptor (CAR) T cell therapy prior to BiAb and 5 patients were exposed to a BCMA antibody-drug conjugate prior to the BiAb. Furthermore, 89% of patients were triple-class refractory while 44% were penta-refractory. Following treatment with a BiAb, 2 patients were lost to follow up, 1 patient decided to be monitored off treatment and 61 patients received a median of 2 lines of therapy (range: 1-8). Most common therapies included a second BiAb (n=20; 33%), CAR T cells (n=15; 26%) or intensive chemotherapy (n=36; 59%) such as melphalan, carmustine or VDPACE with stem cell rescue (n=13) or DCEP (n=23). Best response to initial treatment following the BiAb varied widely and included 12 complete responses, 5 very good partial responses, 17 partial responses, 2 minimal responses, 10 stable disease and 13 progressed disease for an overall response rate (ORR) of 58%. Encouraging responses were seen in 10 patients who directly transitioned from one BiAb to another and 8 patients who directly transitioned to CAR T cell therapy. The progression-free survival of those 18 patients who directly transitioned to a T cell directed therapy was 28.9 months (95% CI: 21.6-NE) and their median overall survival was not reached. Furthermore, the overall survival for the whole cohort of patients was 17.6 months (95% CI: 12.0-NE). Conclusion: Our data suggests that heavily pretreated, predominantly triple-class refractory, patients relapsing after BiAbs may still have good outcomes when sequentially treating with other immunological/T cell-directed therapeutics such as BiAbs and CAR T cells. Studying the appropriate sequence of these treatments is of paramount importance as BiAbs are expected to become part of the standard of care for RRMM patients. Disclosures Richard: Karyopharm, Janssen: Honoraria. Richter: Celgene: Speakers Bureau; Adaptive Biotechnologies: Speakers Bureau; Celgene: Consultancy; Janssen: Consultancy; BMS: Consultancy; Karyopharm: Consultancy; Antengene: Consultancy; Sanofi: Consultancy; X4 Pharmaceuticals: Consultancy; Oncopeptides: Consultancy; Adaptive Biotechnologies: Consultancy; Janssen: Speakers Bureau; Secura Bio: Consultancy; Astra Zeneca: Consultancy. Chari: Janssen Pharmaceuticals: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Novartis Pharmaceuticals: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Pharmacyclics: Research Funding; Seattle Genetics: Consultancy, Research Funding; Takeda Pharmaceutical Company: Consultancy, Research Funding; Karyopharm: Consultancy; Sanofi Genzyme: Consultancy; Oncopeptides: Consultancy; Antegene: Consultancy; Glaxosmithkline: Consultancy; Secura Bio: Consultancy. Parekh: Foundation Medicine Inc: Consultancy; Amgen: Research Funding; PFIZER: Research Funding; CELGENE: Research Funding; Karyopharm Inv: Research Funding.

Background Anti-BCMA chimeric antigen receptor (CAR) T have shown remarkable efficacy in highly pretreated multiple myeloma (MM) patients. With recent FDA approval of BCMA-targeted CAR T in MM and other agents in late stages of development, CAR T is poised to become more widely used. However, the outcomes of MM patients after relapse on CAR T are largely unknown and effective approaches to salvage after CAR T are urgently needed. Methods Demographics, disease characteristics and post-clinical trial outcomes were collected retrospectively on 31 MM patients who relapsed after CAR T therapy at a single academic hospital. Results 31 MM patients had a median age of 61 years at time of disease progression after CAR T; 19 (61%) were male. Median time from diagnosis to CAR T relapse was 74 months (range 22-282). Post-CAR T follow-up was a median of 391 days (range 86-943). Twenty-six patients (84%) had high-risk cytogenetics. Most patients were highly pretreated with a median of 5 prior lines (range 1-18) and 28 patients (90%) had received autologous stem cell transplant (ASCT). Patient exposure/refractoriness included: lenalidomide (100%/74%), pomalidomide (87%/84%), bortezomib (90%/61%), carfilzomib (94%/87%), CD38-mAb (97%/97%) and alkylating agents (100%/54). Fifteen patients (48%) had received DCEP and four patients (13%) had received prior treatment with a non-BCMA-targeted bispecific Ab. The median time to a subsequent treatment following relapse on CAR T was 34 days (range 0-378). At time of analysis, patients had already received a median of 2 subsequent treatment lines (range 1-8). The most common initial treatment after CAR T relapse was chemotherapy with V-DCEP or VD-PACE (10/29, 34%). Stem cell boost was part of the initial approach in five patients (17%) and was performed in 12 patients at any time after CAR T relapse (41%). Five patients (17%) were treated with bispecific Ab immediately after CAR T and 11 patients (38%) received bispecific Ab therapy at any point after CAR T. Best response to initial treatment varied widely (10 PD, 4 SD, 1 MR, 1 PR, 6 VGPR, 7 CR) with overall response rate (ORR, ≥PR) of 48%. Median time to progression was 104 days for the initial treatment and 62 days for the second line after CAR T. Twenty occurrences of durable responses (>120 days, range 126-513) were observed, of which were 4 selinexor-based treatments, 4 with non-BCMA bispecific Ab, 4 involving stem cell boost and 2 venetoclax-based. At the time of analysis, 17 patients (55%) were alive and the median OS after relapse on CAR T was 496 days. Conclusion Studying the prognosis of patients after relapse and the response to subsequent therapy will provide important clinical insights for salvage, especially as CAR T moves to an earlier treatment setting. At the meeting, we will compare and contrast more mature data on the CAR T cohort with >50 patients that relapsed after bispecific Ab therapy.

Acute myeloid leukemia (AML) is a highly heterogeneous disease arising from acquired genetic and epigenetic aberrations which stifle normal development and differentiation of hematopoietic precursors. Despite the complex and varied biological underpinnings, induction therapy for AML has remained fairly uniform over 4 decades and outcomes remain poor for most patients. Recently, enhanced understanding of the leukemic epigenome has resulted in the translational investigation of a number of epigenetic modifying agents currently in various stages of clinical development. These novel therapies are based on mechanistic rationale and offer the potential to improve AML patient outcomes. In light of many recent advances in this field, we provide an updated, clinically oriented review of the evolving landscape of epigenetic modifying agents for the treatment of AML.

A 70-year-old African-American male presented to the emergency room for 1 month of fatigue, progressive dyspnea on exertion, and easy bruising. He endorsed a past medical history significant for insulin-dependent diabetes, chronic kidney disease, and nonischemic cardiomyopathy. He denied a family history of malignancy and noted he was a retired army mechanic with prior exposure to Agent Orange. At triage, his vital signs were within normal limits. His physical exam revealed pale mucous membranes, a normal cardiopulmonary exam, no hepatosplenomegaly, and trace peripheral edema. A complete blood count showed leukocytosis of 26,450 cells/μL comprised of 2.1% neutrophils, 11.8% lymphocytes, and 86.1% blasts. He had a normocytic anemia with hemoglobin 9.3 g/dL and thrombocytopenia of 18,000 platelets/μL. Coagulation studies identified an elevated international normalized ratio (INR) of 1.6 (normal ≤1.1) and prothrombin time of 17.1 s (normal 8.9–11.4 s) and a decreased fibrinogen of 106 mg/dL (normal 217–420 mg/dL). A peripheral blood smear presented numerous circulating immature myeloid cells intermediate in size with scant cytoplasm, azurophilic granules, and folded nuclei (Fig. 15.1).

Introduction: Lenalidomide (R) maintenance therapy in multiple myeloma (MM) has been shown to improve progression-free survival (PFS) and overall survival (OS) after autologous stem-cell transplantation (ASCT). Even in the transplant ineligible population, R until progression is associated with improved PFS. The ever-increasing use of R maintenance therapy, however, eventually leads to refractoriness to R at maintenance doses. Moreover, clinical trials with len-dex (Rd) backbone regimens including daratumumab, elotuzumab, ixazomib, and carfilzomib have all excluded such patients (pts). This is particularly an issue for elotuzumab and ixazomib, which have no single agent approval. There are currently no published data on the outcomes of full dose Rd or Rd backbone containing regimens in pts refractory to R maintenance. A prospective randomized trial would be difficult to perform given variability in pt factors (i.e. R tolerance, age, renal function) and disease factors (i.e. molecular risk and clinical vs biochemical progression). We therefore performed a retrospective study to characterize outcomes of pts on R maintenance therapy. Methods: This is a single-institution, retrospective study in which we reviewed the records of all consecutive pts with a diagnosis of MM at the Mount Sinai Hospital between February 2010 and October 2016. There were 465 pts identified who had maintenance R as a single agent or in combination with low-dose dexamethasone or prednisone. Pts were excluded if insufficient data were available or < 3 month (mo) follow up from time of initiation of R maintenance. Time to progression (TTP) on R maintenance, next line of therapy, and PFS on next line of therapy were determined using Kaplan Meyer analysis. Results: A total of 350 pts were included in this study. Baseline characteristics are summarized in Table 1. The median follow up time was 59 mos and median time on R maintenance was 21.0 mos. 172 pts (49%) progressed while on R maintenance or within 60 days of R discontinuation. 51 pts (15%) remain on R maintenance as of last follow up. The remaining 127 pts (36%) discontinued R for reasons other than progression and either progressed after 60 days (median 658 days, range 91-2053 days) or have not progressed. The median TTP on R maintenance was 34.2 mos (Fig 1A) and the majority of these were characterized by the treating physician as biochemical (65% during maintenance and 56% after R discontinuation). Of the patients with serologic and symptomatic progression, the majority were by bone disease (24% and 37%, respectively). 234 pts had data available on next line of therapy and the median PFS on this next line was 16.8 mo (95% CI: 13.2-20.1), however the PFS was shorter for those who had progressed while on R maintenance versus those who had progressed after R maintenance had been discontinued (13.2 mos vs. 28.9 mos, respectively, p 0.0001). The median PFS according to next line of therapy for those who received an increase in R dose + dex vs 3rd agent added to Rd backbone vs total change in therapy was 9.5 mos vs 21.0 mos vs 14.2 mos, respectively (Fig 1B). The most common drugs added to an Rd backbone were bortezomib and elotuzumab with an associated PFS of 19.0 and 40.1 mos, respectively. The majority of those receiving elotuzumab + Rd had progressed on R maintenance (15/18 = 83%). The most common regimens for those with a total change in therapy are summarized in Table 2. Conclusions: The median TTP on R maintenance was 34.2 mos and while most progression was felt to be biochemical, of those with symptomatic progression as well, the primary manifestation was bone disease (approximately 30% of patients), highlighting the importance of surveillance osseous imaging in MM. While an increase in R dose with steroids was associated with an additional 9.5 mos PFS and a total change in regimen with 14.2 mos PFS, those who received an Rd containing triplet had impressive results. In particular, Rd + elotuzumab resulted in a PFS of 40.1 mos. Multivariate analysis accounting for the potential confounding patient and disease factors inherent to treatment selection in retrospective studies will be presented at the meeting. Disclosures Cho: BMS: Consultancy; GSK: Consultancy; Takeda: Research Funding; The Multiple Myeloma Research Foundation: Employment; Genentech: Honoraria, Research Funding; Agenus: Research Funding; Celgene: Honoraria, Research Funding. Jagannath:Celgene: Consultancy; Novartis: Consultancy; Merck: Consultancy; Medicom: Speakers Bureau; Multiple Myeloma Research Foundation: Speakers Bureau; BMS: Consultancy. Madduri:Abbvie: Consultancy; Takeda: Consultancy; Celgene: Consultancy; undation Medicine: Consultancy. Parekh:Celgene Corporation: Research Funding; Karyopharm Inc.: Research Funding; Foundation Medicine Inc.: Consultancy. Richter:Adaptive Biotechnologies: Membership on an entity's Board of Directors or advisory committees; Amgen: Consultancy, Speakers Bureau; Bristol-Meyers Squibb: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Janssen: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Karyopharm: Membership on an entity's Board of Directors or advisory committees; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees; Takeda: Membership on an entity's Board of Directors or advisory committees. Chari:Millennium/Takeda: 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; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Karyopharm: Consultancy, Membership on an entity's Board of Directors or advisory committees; Array Biopharma: Research Funding; GlaxoSmithKline: Research Funding; Novartis Pharmaceuticals: Research Funding; Oncoceutics: Research Funding; Pharmacyclics: Research Funding; Sanofi: Membership on an entity's Board of Directors or advisory committees; Seattle Genetics: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bristol-Myers Squibb: Consultancy; Celgene: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding.

Race, Socioeconomic Status, and Time to Transplantation in Multiple Myeloma Background: Multiple myeloma is the most common hematologic malignancy in blacks. Previous studies have found that black patients undergo autologous stem cell transplant (ASCT) less frequently than their white counterparts, though the reasons for this have not been fully elucidated. To identify whether racial differences in timing of referrals to transplant centers and transplantation may play a role in this observed disparity, we analyzed data from transplants undergone at The Mount Sinai Hospital between 2011 and 2016. Methods: We retrospectively analyzed 416 black and white patients who received their first autologous stem cell transplant for multiple myeloma at The Mount Sinai Hospital between 2011 and 2016. We compared the time from initial diagnosis to stem cell harvest and the time from harvest to transplant between the two groups while controlling for age, socioeconomic status, and functional status. Results: In total, 264 white patients and 152 black patients were identified as receiving their first transplant between 2011 and 2016. Data regarding each patient's demographic, date of diagnosis, date of harvest and transplant, and functional status were available. Age, socioeconomic status (as assessed through census data of median income of the patients' zip code), and functional status were considered possible confounders. Linear regression analysis was used to assess differences in transplant timing between races while controlling for these factors. We found that between racial groups, neither the time from diagnosis to harvest (528 days vs. 406 days respectively, p=.95) nor the time from harvest to transplant (113 days vs. 150 days respectively, p=.31) was significantly different. Age and socioeconomic status also did not significantly affect either time point, although patients with higher socioeconomic status had a decreased time from diagnosis to harvest which approached significance (p=0.07) regardless of their race. Finally, better functional status was associated with a shorter time from diagnosis to harvest (p=0.003). Conclusion: Based on these findings, race and socioeconomic status did not significantly affect expediency of referral to and completion of transplantation following initial disease diagnosis. Further studies are needed to clarify the factors contributing to observed differences in ASCT utilization between blacks and whites. Disclosures No relevant conflicts of interest to declare.