Abstract: Multiple myeloma (MM) is accompanied by alterations to the normal plasma cell (PC) proteome, leading to changes to the tumor microenvironment and disease progression. There is a great need for understanding the consequences that lead to MM progression and for the discovery of new biomarkers that can aid clinical diagnostics and serve as targets for therapeutics. This study demonstrates the applicability of utilizing the single-cell high-definition liquid biopsy assay (HDSCA) and imaging mass cytometry to characterize the proteomic profile of myeloma. In our study, we analyzed ~87,000 cells from seven patient samples (bone marrow and peripheral blood) across the myeloma disease spectrum and utilized our multiplexed panel to characterize the expression of clinical markers for PC classification, additional potential therapeutic targets, and the tumor microenvironment cells. Our analysis showed BCMA, ICAM3 (CD50), CD221, and CS1 (SLAMF7) as the most abundantly expressed markers on PCs across all myeloma stages, with BCMA, ICAM3, and CD221 having significantly higher expression levels on disease versus precursor PCs. Additionally, we identify significantly elevated levels of expression for CD74, MUM1, CD229, CD44, IGLL5, Cyclin D1, UBA52, and CD317 on PCs from overt disease conditions compared to those from precursor states.

Abstract: A longer duration of maintenance lenalidomide after autologous hematopoietic stem cell transplantation for multiple myeloma is associated with prolonged survival. There is no survival difference between initiating maintenance lenalidomide early ( 〈 4 months) and initiating it late (≥4 months). The incidence of second primary malignancies is 3%. See also pages 3762‐4.

Abstract: TP53 gene deletion is associated with poor outcomes in multiple myeloma (MM). We report the outcomes of patients with MM with and without TP53 deletion who underwent immunomodulatory drug (IMiD) and/or proteasome inhibitor (PI) induction followed by autologous hematopoietic stem cell transplant (auto‐HCT). We identified 34 patients with MM and TP53 deletion who underwent IMiD and/or PI induction followed by auto‐HCT at our institution during 2008–2014. We compared their outcomes with those of control patients ( n  = 111) with MM without TP53 deletion. Median age at auto‐HCT was 59 years in the TP53 ‐deletion group and 58 years in the control group ( P  = 0.4). Twenty‐one patients (62%) with TP53 deletion and 69 controls (62%) achieved at least partial remission before auto‐HCT ( P  = 0.97). Twenty‐three patients (68%) with TP53 deletion and 47 controls (42%) had relapsed disease at auto‐HCT ( P  = 0.01). Median progression‐free survival was 8 months for patients with TP53 deletion and 28 months for controls ( P   〈  0.001). Median overall survival was 21 months for patients with TP53 deletion and 56 months for controls ( P   〈  0.001). On multivariate analysis of both groups, TP53 deletion (hazard ratio 3.4, 95% confidence interval 1.9–5.8, P   〈  0.001) and relapsed disease at auto‐HCT (hazard ratio 2.0, 95% confidence interval 1.2–3.4, P  = 0.008) were associated with a higher risk of earlier progression. In MM patients treated with PI and/or IMiD drugs, and auto‐HCT, TP53 deletion and relapsed disease at the time of auto‐HCT are independent predictors of progression. Novel approaches should be evaluated in this high‐risk population. Am. J. Hematol. 91:E442–E447, 2016. © 2016 Wiley Periodicals, Inc.

Abstract: Chimeric antigen receptor (CAR) T cells expressing B-cell maturation antigen (BCMA) can target and kill multiple myeloma (MM). BCMA was chosen as a target for MM because it is expressed by almost all cases of MM but has a restricted expression pattern on normal cells. CAR antigen-recognition domains made up of monoclonal antibody-derived, single-chain-variable fragments (scFv) are potentially immunogenic. To reduce the risk of recipient immune responses against CAR T cells, we used the sequence of a novel anti-BCMA, fully-human, heavy-chain-only binding domain designated FHVH33. The FHVH33 binding domain sequence was from TeneoBio, Inc. FHVH33 is smaller than a scFv. FHVH33 lacks the light chain, artificial linker sequence, and 2 associated junctions of a scFv, so it is predicted to be less immunogenic than a scFv, especially murine-derived scFvs. We constructed a CAR incorporating FHVH33, CD8α hinge and transmembrane domains, a 4-1BB costimulatory domain, and a CD3ζ T-cell activation domain. The CAR, FHVH33-CD8BBZ, is encoded by a γ-retroviral vector. FHVH33-CD8BBZ-expressing T cells (FHVH-BCMA-T) exhibited a full range of T-cell functions in vitro and eliminated tumors and disseminated malignancy in mice (Lam et al, Blood (ASH abstract) 2017 vol 130: 504). We are conducting the first clinical trial of FHVH-BCMA-T. Patients receive conditioning chemotherapy on days -5 to -3 with 300 mg/m2 of cyclophosphamide and 30 mg/m2 of fludarabine followed by infusion of FHVH-BCMA-T on day 0. This dose-escalation trial has 5 planned dose levels (DL). Twelve patients have received FHVH-BCMA-T on 3 DLs, 0.75x106, 1.5x106 and 3x106 CAR+ T cells/kg of bodyweight. Three patients were enrolled on the trial but not treated. The median age of patients enrolled was 63 (range 52-70); patients received a median of 6 lines of anti-myeloma therapy (range 3-10) prior to treatment with FHVH-BCMA-T. Ten patients out of 12 patients have achieved objective responses (OR). Five patients have obtained CRs or VGPRs to date. One patient achieved a partial remission (PR) 26 weeks after FHVH-BCMA-T infusion through a continued decrease in a measurable plasmacytoma. Five out of 7 patients who had myeloma with high-risk cytogenetics had an OR (Table). ORs occurred in patients with large soft-tissue plasmacytomas. Loss of BCMA expression on myeloma cells after treatment was documented in 2 patients. Two patients who developed progressive MM after CAR T-cell infusion had evidence of minimal residual disease in bone marrow 1-2 months post infusion of CAR T cells (patients 7,8). Eleven out of 12 patients had cytokine release syndrome (CRS); CRS grades ranged from 1-3 (Lee et al. Biol Blood Marrow Transplant 25 (2019) 625-638). The median peak C reactive protein (CRP) of the patients with CRS was 156.3 mg/L. Of 12 patients, 1 received the interleukin-6-receptor antagonist tocilizumab on day +6 to treat grade 3 CRS with hypotension requiring low-dose pressor therapy, grade 2 ejection fraction (EF) decrease and elevation of creatinine kinase (CK). All parameters returned to baseline by day +10. Patient 12 had a grade 3 decrease in EF which resolved by day +29. Two patients had grade 2 neurotoxicity that resolved without intervention: patient 3 had headaches, dysarthria and word-finding difficulties that resolved after 6 days while patient 6 had headaches on day +4. Patient 12 had grade 3 neurotoxicity with confusion on day +2; she was given dexamethasone with improvement in mental status the same day. After attaining a response, patient 6 died from influenza complications 6 weeks after FHVH-BCMA-T infusion. A median of 10.6% (range 1.1-46) of bone marrow T cells were CAR+ when assessed 14 days after FHVH-BCMA-T infusion. We assessed blood CAR+ cells by quantitative PCR. The median peak level of CAR+ cells was 76.5 cells/µl (range 3-347 cells/µl) and the median day post-infusion of peak blood CAR+ cell levels was 13 (range 9-14). The results from this phase 1 trial demonstrate that FHVH-BCMA-T cells can induce responses at low dose levels. Patients who had no CRS or low-grade CRS achieved objective responses. Toxicity was limited and reversible. Accrual to this trial continues. A maximum tolerated dose has not been determined yet. These results encourage further development of FHVH CAR-T. Table Disclosures Manasanch: Janssen: Honoraria; Sanofi: Honoraria; Takeda: Honoraria; Merck: Research Funding; Skyline Diagnostics: Research Funding; Sanofi: Research Funding; Quest Diagnostics: Research Funding; Celgene: Honoraria. Trinklein:Teneobio, Inc.: Employment, Equity Ownership. Buelow:Teneobio, Inc.: Employment, Equity Ownership. Kochenderfer:Kite and Celgene: Research Funding; Bluebird and CRISPR Therapeutics: Other: received royalties on licensing of his inventions. OffLabel Disclosure: Cyclophosphamide and fludarabine are used in combination for conditioning chemotherapy prior to CAR T-cell infusion

Abstract: Background: The role of maintenance lenalidomide (Len) in the post autologous stem cell transplant (ASCT) setting has been based on a significant benefit in progression-free survival (PFS) and time to progression (TTP) in the CALBG 100104 and IFM 2005-02 trials, and overall survival (OS) benefit in the CALBG100104 trial. To date, the use of a proteasome inhibitor (PI) as maintenance therapy has been limited by the inconvenience of its IV/subcutaneous administration. Ixazomib, an oral PI, may provide an alternative maintenance therapy. Here we report the results of a single arm phase II study combining ixazomib and lenalidomide as post ASCT maintenance therapy in patients with newly diagnosed multiple myeloma (NDMM). Methods: This is a single arm phase II study of the combination of lenalidomide/ixazomib (LI) maintenance therapy for NDMM paients post ASCT. The primary objective was to establish safety and efficacy of Len as maintenance therapy. The secondary objectives were to evaluate the incidence of secondary primary malignancies (SPMs), overall response rate (sCR/nCR/VGPR/PR), TTP, time to next therapy, and toxicity profile. Eligible patients had undergone ASCT, with melphalan as a preparative regimen, within 12 months of initiation of induction therapy. Patients were required to start maintenance therapy 60-180 days post ASCT. Treatment consisted of 28 day cycles of ixazomib 4 mg on days 1, 8, 15, and lenalidomide 10 mg daily on days 1-28. Len was increased to 15 mg after 3 months if well tolerated. Based on clinical experience from ongoing phase III studies, the protocol was later amended to reduce the starting dose of ixazomib to 3 mg. Adverse events were graded by NCI-CTCAE v4. Response was assessed by the modified International Uniform Response Criteria. Results: 65 patients (pts) were enrolled with a median age of 60 (range 39-74); 65% (42/65) were male. 39 pts had ISS stage I disease, 13 had Stage II; and 13 had stage III. Of the 65 pts, 47 remain on therapy and as of June 2015, pts have received a median of 10 cycles (range 1-30). The median PFS has not been reached however, the estimated 2-year PFS was 83%. 18 pts are off study: 7 due to progressive disease (PD), 3 at PI discretion, and 8 due to consent withdrawal. 6/7 pts with PD had high risk disease and received 2, 5, 7, 7, 9, 11, and 24 cycles of study therapy. Among the 7 pts with PD, the median PFS post ASCT was 13 months (6-34 months); 3 pts have died with an OS of 15, 27 and 31 months. Grade 3/4 hematologic adverse events (AEs) included: grade 3 (G3) anemia (2), G3 neutropenia (13), G4 neutropenia (2); and G3/4 thrombocytopenia (7). Grade 3/4 drug-related non-hematologic AEs included: G3 elevated aspartate aminotransferase (3); G3 back pain (2); G3 constipation (4); G3 creatinine increase (2); G3 nausea and diarrhea (2); G3 fatigue (4). 10 pts had G1/2 rash and 8 pts had G3 rash. 42 patients had G1/2 peripheral neuropathy (PN); 1 pt had G3 PN; and 2 pts had G3/4 respiratory failure. There were no second primary malignancies. Infectious complications included G3 urinary tract infections (2); G3/4 upper respiratory tract infections (4); G3 sinusitis (1); G3 pneumonia (7); G3 influenza (2); G4 infection (1). Other AEs included G4 renal failure due to progressive disease (1); G3 non cardiac chest pain (1); G3 emesis (1); G4 respiratory failure and G4 sepsis/respiratory failure (2). 10 patients required a dose reduction of ixazomib for PN (5); neutropenia (3); thrombocytopenia (1), and hearing loss (1). 1 pt discontinued ixazomib and remained on Len due to persistent PN. 11 pts had a dose reduction in Len to 10 mg for 21 of a 28 day cycle due to cytopenias (neutropenia or thrombocytopenia); 5 pts had a dose reduction to 5 mg due to rash/pruritus in 4 pts and 1 pt due to neutropenia. Conclusions: Long term administration of combination of lenalidomide/ixazomib as maintenance therapy post ASCT is feasible with pts ongoing at 30+ cycles. The incidence of adverse events was similar to historical experience with lenalidomide alone; hematologic adverse events were manageable with dose reductions. The incidence of PN was limited to grade 1/2 events and 1 grade 3 event with no other unexpected toxicity. The combination is safe, feasible, well tolerated and experience to date supports further exploration in phase III studies. Disclosures Shah: Celgene: Consultancy, Research Funding. Thomas:Celgene: Research Funding; Novartis: Research Funding; Idera Pharmaceuticals: Research Funding. Wang:Celgene: Research Funding. Orlowski:Celgene: Consultancy, Research Funding; Array BioPharma: Consultancy, Research Funding; Acetylon: Membership on an entity's Board of Directors or advisory committees; Genentech: Consultancy; Millennium Pharmaceuticals: Consultancy, Research Funding; Spectrum Pharmaceuticals: Research Funding; Onyx Pharmaceuticals: Consultancy, Research Funding; Bristol-Myers Squibb: Consultancy, Research Funding; Forma Therapeutics: Consultancy; BioTheryX, Inc.: Membership on an entity's Board of Directors or advisory committees; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees.

Abstract: Introduction: Multiple myeloma (MM) remains incurable with only a small proportion of patients surviving over 10 years (long-term survivors) from diagnosis. It has been more than 3 decades since the first autologous stem cell transplantation (ASCT) was performed for MM at our institution. In this study, we sought to determine baseline patient and disease characteristics that are associated with long-term survival after the ASCT. Methods: We included all consecutive patients who received their first ASCT between January 1988 and December 2015. The primary objective was to identify the variables associated with long-term overall survival ( & gt;10 years). The control group were patients who survived less than 10 years from their diagnosis data (short-term survivors). Logistic regression models were used to evaluate the association between predictive factors and overall survival of & gt; 10 years. Results: Among 2176 patients who underwent their first ASCT during the study period, 1409 patients met the eligibility criteria. Overall, 392 (28%) patients were long-term survivors ( & gt;10 years) and 1017 (72%) were short-term survivors ( & lt;10 years). Table 1 shows baseline patient and disease characteristics. Only 24% and 42% of patients in the long-term and short-term survivor groups, respectively, received proteasome inhibitor-based induction therapies. Maintenance therapy was received by 49% and 45% in the short- and long-term survivor groups, respectively (p=0.19). The long-term survivor group was characterized by having higher percentage of patients younger than age 65 (86%) years, and having higher proportions of ISS Stage I (47%), standard-risk cytogenetics (96%), normal LDH (88%) and with serum creatinine & lt;2 mg/d (87%). With a median follow-up of 13 years (range, 10-30 years), the 15-year PFS and OS survival rates in the long-term survivors were 19% (95% CI: 14% - 23%) and 62% (95%: CI 56% - 68%) (Figure 1A). The cumulative incidence rates of relapse at 1, 3, and 5 years in the short-term survival group were 9%, 63%, and 82%, respectively, compared to 2%, 20%, and 40%, respectively, in the long-term survivor group (p & lt;0.001) (Figure 1B). All variables listed in Table 1 were assessed in univariate analysis. Seventy-six percent of patients were relapse-free at 24 months in the long-term survival group, compared to only 32% in the short-term survival group. On multivariable analysis, age, cytogenetic-risk status, race-ethnicity, and duration of remission after ASCT were significant predictors for surviving & gt; 10 years (Table 2). ISS Stage III (vs. Stage I: OR 0.45, 95% CI 0.19-1.09; p=0.08) showed a trend towards surviving ≤ 10 years. Conclusions: ASCT is associated with durable responses and prolonged survival in a subgroup of MM patients irrespective of type of induction therapy and/or use of maintenance therapy. Duration of remission after transplant is the strongest predictor for long-term survival. Age & lt;65 years, being African-American, and standard-risk cytogenetics were also associated with surviving more than 10 years. Disclosures Bashir: Acrotech: Research Funding; StemLine: Research Funding; Celgene: Research Funding; Amgen: Other: Advisory Board; Purdue: Other: Advisory Board; Takeda: Other: Advisory Board, Research Funding; KITE: Other: Advisory Board. Nieto:Affimed: Consultancy, Other: Grant Support; Novartis: Other: Grant Support; Astra Zeneca: Other: Grant Support; Secura Bio: Other: Grant Support. Mehta:CSL Behring: Research Funding; Incyte: Research Funding; Kadmon: Research Funding. Ciurea:Kiadis Pharma: Current equity holder in publicly-traded company, Research Funding. Popat:Bayer: Research Funding; Novartis: Research Funding. Khouri:Bristol Myers Squibb: Research Funding; Pfizer: Research Funding. Kebriaei:Ziopharm: Other: Research Support; Novartis: Other: Served on advisory board; Pfizer: Other: Served on advisory board; Jazz: Consultancy; Kite: Other: Served on advisory board; Amgen: Other: Research Support. Manasanch:GSK: Honoraria; Adaptive Biotechnologies: Honoraria; Merck: Research Funding; Quest Diagnostics: Research Funding; Takeda: Honoraria; BMS: Honoraria; Sanofi: Research Funding; Novartis: Research Funding; Sanofi: Honoraria; JW Pharma: Research Funding. Hosing:NKARTA Inc.: Consultancy. Patel:Janssen: Consultancy, Research Funding; Nektar: Consultancy, Research Funding; Cellectis: Research Funding; Poseida: Research Funding; Oncopeptides: Consultancy; Precision Biosciences: Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Takeda: Consultancy, Research Funding. Lee:Regeneron: Research Funding; Amgen: Consultancy, Research Funding; Genentech: Consultancy; Sanofi: Consultancy; Janssen: Consultancy, Research Funding; Takeda: Consultancy, Research Funding; Genentech: Consultancy; Daiichi Sankyo: Research Funding; Celgene: Consultancy, Research Funding; GlaxoSmithKline: Consultancy, Research Funding. Shpall:Zelluna: Membership on an entity's Board of Directors or advisory committees; Takeda: Other: Licensing Agreement; Adaptimmune: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Magenta: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees. Orlowski:Laboratory research funding from BioTheryX, and clinical research funding from CARsgen Therapeutics, Celgene, Exelixis, Janssen Biotech, Sanofi-Aventis, Takeda Pharmaceuticals North America, Inc.: Research Funding; Founder of Asylia Therapeutics, Inc., with associated patents and an equity interest, though this technology does not bear on the current submission.: Current equity holder in private company, Patents & Royalties; STATinMED Research: Consultancy; Sanofi-Aventis, Servier, Takeda Pharmaceuticals North America, Inc.: Honoraria, Membership on an entity's Board of Directors or advisory committees; Amgen, Inc., AstraZeneca, BMS, Celgene, EcoR1 Capital LLC, Forma Therapeutics, Genzyme, GSK Biologicals, Ionis Pharmaceuticals, Inc., Janssen Biotech, Juno Therapeutics, Kite Pharma, Legend Biotech USA, Molecular Partners, Regeneron Pharmaceuticals, Inc.,: Honoraria, Membership on an entity's Board of Directors or advisory committees. Champlin:Omeros: Consultancy; Cytonus: Consultancy; Johnson and Johnson: Consultancy; Actinium: Consultancy; Genzyme: Speakers Bureau; Takeda: Patents & Royalties; DKMS America: Membership on an entity's Board of Directors or advisory committees. Qazilbash:Bioclinica: Consultancy; Amgen: Research Funding; Janssen: Research Funding; Angiocrine: Research Funding; Bioline: Research Funding.