Gonsalves, Wilson I.

Abstract Background: Chimeric antigen receptor T cell therapy (CAR-T) is a recent therapeutic advance for the treatment of myeloma. Among the FDA approved and investigational CAR-T, primary refractory disease post CAR-T infusion is uncommon, however most patients eventually relapse. To gain insight to the myeloma cell and immune cell characteristics associated with early relapse (PD) versus durable response (DR), we examined myeloma cells and immune cells in both the bone marrow and blood by single cell RNA-seq. Method: Bone marrow aspirate and blood samples were collected prior to BCMA targeted CAR-T therapy. CD138 + and CD138 neg cells from bone marrow (BM) and peripheral blood mononuclear cells (PBMNC) were collected for 5' based scRNA-seq (10X Genomics). CD138 + cells were clustered by Harmony integration. Top expressing genes in unique clusters for PD and DR were analyzed by Ingenuity Pathway Analyses. To profile CD138 neg BM cells and PBMNC from myeloma patients, the scRNA-seq dataset was mapped to the human PBMC reference using the Seurat v4 reference-guiding approach. Differential gene expression between responders and non-responders was performed using the FindMarkers function for each of the immune cell clusters in the BM and PB. Results: BM and PB samples from 15 patients were analyzed. Among these, 5 patients had relapsed disease more than 1-year post CAR-T infusion (Durable Response, DR), and 10 patients had relapse within 1 year (early relapse, PD). Among these, CD138+ cells were available from 3 DR and 4 PD for analysis. Multimodal expression of BCMA were seen among the CD138+ cells across all samples. Using the mode of the highest expression level as a cut-off, patients with DR had a trend toward having higher fraction of BCMA high CD138+ cells compared to pts with PD. Clustering of all CD138+ cells by Harmony integration identified 12 distinct clusters, among which two clusters were unique to pts in DR, and one was unique to patients in PD. Ingenuity pathway analysis identified the top marker genes in these 3 clusters to be enriched in pathways for IL-15 signaling, BCR signaling, and primary immunodeficiency signaling. (Figure 1A-E.) Differential gene expression for immune cell clusters from CD138 neg BM cells and PBMNC were compared between pts in PD and DR. Interestingly, different patterns were seen in immune cells in PB and BM (Figure 1G). For example, compared to pts in PD, those with DR had decreased signaling in CD16 PB monocytes for interferon signaling and differentiation to macrophages, whereas the CD16 monocytes in the BM in pts in DR had increased expression of mitochondrial genes for anti-oxidant stress, polarization to M1 macrophage and anti-apoptosis. Similarly, pts in DR had CD8 Tcm in the BM with increased expression of genes involved in cell adhesion and anti-apoptosis, and CD4 Tcm in the BM with increased expression of genes in protein metabolism. Conclusion: scRNAseq analysis of myeloma cells suggest different tumor transcriptome profile may be identified in myeloma cells that could relapse early after CAR-T therapy. In addition, host immune profile both in the BM microenvironment and in systemic PB circulation could be associated with durable clinical response. Figure 1 Figure 1. Disclosures Kapoor: Pharmacyclics: Consultancy; Glaxo SmithKline: Research Funding; Amgen: Research Funding; Sanofi: Research Funding; AbbVie: Research Funding; Ichnos Sciences: Research Funding; Sanofi: Consultancy; Regeneron Pharmaceuticals: Research Funding; Takeda: Research Funding; Karyopharm: Research Funding; Karyopharm: Consultancy; Cellectar: Consultancy; BeiGene: Consultancy. Dingli: GSK: Consultancy; Janssen: Consultancy; Sanofi: Consultancy; Novartis: Research Funding; Apellis: Consultancy; Alexion: Consultancy. Kumar: Bluebird Bio: Consultancy; Janssen: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; Novartis: Research Funding; BMS: Consultancy, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Roche-Genentech: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Antengene: Consultancy, Honoraria; Carsgen: Research Funding; Oncopeptides: Consultancy; Beigene: Consultancy; Amgen: Consultancy, Research Funding; Merck: Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Lin: Merck: Research Funding; Kite, a Gilead Company: Consultancy, Research Funding; Takeda: Research Funding; Bluebird Bio: Consultancy, Research Funding; Celgene: Consultancy, Research Funding; Sorrento: Consultancy; Juno: Consultancy; Legend: Consultancy; Gamida Cell: Consultancy; Vineti: Consultancy; Novartis: Consultancy; Janssen: Consultancy, Research Funding.

Abstract Background: GLUT4 inhibition is an attractive therapeutic option in multiple myeloma (MM) given the dependence of MM cells on glucose transport. Furthermore, combining a GLUT4 inhibitor with an oxidative phosphorylation inhibitor in MM cells to counter the possibility of therapeutic resistance to GLUT4 inhibition has demonstrated synergistic promise (Dalva-Aydemir et al, Clin Can Res 2015). Using a GLUT4 inhibitor such as the HIV protease inhibitor nelfinavir is an attractive choice since it not only inhibits the transport function of GLUT4, but it also lowers the cytotoxicity resistance of MM cells against proteasome inhibitors such as bortezomib (Driessen et al, Blood 2018). Thus, in summary the FDA-approved oral HIV-PI nelfinavir, long used for the treatment of HIV disease, can bind to glucose transporters (GLUT4) on MM cells and reversibly inhibit glucose uptake, thus disrupting the Warburg effect. Nelfinavir can also enhance the activity of PIs such as bortezomib overcome its resistance in MM cells. Metformin, an oral FDA-approved drug for the treatment of Type II Diabetes has the ability to disrupt the electron transport chain of defective mitochondria within MM cells, thus blocking the ability of such mitochondria to generate energy and anabolic substrates as compensatory mechanisms required for proliferation in the setting of GLUT4 inhibition. Thus, this study will look at the safety and tolerability of repurposing the existing FDA-approved drugs for Type II diabetes and HIV in combination with bortezomib for the treatment of relapsed and/or refractory myeloma. Methods: This study is a phase 1 clinical trial of metformin and nelfinavir in combination with bortezomib for patients with relapsed and/or refractory myeloma. Part A of this trial is a 3+3 dose escalation design with 3 dose levels planned. Part B is a dose expansion cohort at the Maximal Tolerated Dose (MTD) determined in Part A. Up to a maximum of 36 patients will be enrolled and treated for a maximum of six 21-day cycles. Bortezomib is administered in its usual weekly subcutaneous dosing schedule of days 1, 8 and 15 of a 21-day cycle at a dose level of 1.3 mg/m2. Metformin will be administered for 14 days of a 21-day cycle and started at a dose level of 500 mg twice daily and will be investigated to a maximum dose of 1000 mg twice daily. Nelfinavir will also be administered for 14 days of a 21-day cycle and started at a dose level of 1250 mg twice daily and will be investigated to a maximum dose of 2500 mg twice daily. Key inclusion criteria include having relapsed/refractory myeloma with at least 2 prior lines of therapy and prior exposure to PIs, immunomodulators and Anti-CD38 monoclonal antibodies, adequate hematologic reserve, kidney function and liver function. This trial especially allows patients with non-secretory disease yet measurable by bone marrow assessments or cross-sectional imaging of plasmacytomas to be enrolled which constitutes an unmet need in the real-world MM population. Finally, this allows patients to be treated with a dexamethasone-free regimen. The primary objective of this trial is to determine the MTD of metformin and nelfinavir in combination with bortezomib. The secondary objective is to evaluate the safety and tolerability as well as the overall response rate (ORR) associated with this combination. Potential predictive biomarkers as well as resistance mechanisms using genomic RNA, immunohistochemistry and metabolomics-based assessment platforms will be evaluated in this study. Recruitment is ongoing with no safety concerns. This trial is registered on clinicaltrials.gov: NCT03829020. This investigator-initiated trial was funded by the generous gift of the Helen Diller Family Foundation. Disclosures Kumar: Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Bluebird Bio: Consultancy; Abbvie: 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; Oncopeptides: Consultancy; Antengene: Consultancy, Honoraria; Novartis: Research Funding; Carsgen: Research Funding; Roche-Genentech: Consultancy, Research Funding; Beigene: Consultancy; Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Merck: Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Tenebio: Research Funding; BMS: Consultancy, Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding. Ailawadhi: Karyopharm: Consultancy; AbbVie: Consultancy; Genentech: Consultancy; Takeda: Consultancy; GSK: Consultancy, Research Funding; Xencor: Research Funding; Cellectar: Research Funding; Medimmune: Research Funding; Ascentage: Research Funding; Pharmacyclics: Consultancy, Research Funding; Amgen: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; Bristol Myers Squibb: Consultancy, Research Funding; BeiGene, Ltd.: Consultancy; Sanofi: Consultancy; Oncopeptides: Consultancy.

Abstract Background: Systemic light chain (AL) amyloidosis is a plasma cell disorder characterized by multisystem deposition of misfolded immunoglobulin light chains produced by clonal plasma cells. Hematologic and organ responses with treatment have been shown to correlate with survival as early as 3 months from initiation of first-line treatment. Our group recently developed and validated a model integrating organ and hematologic responses for assessment of treatment outcomes at 6 months. Although current organ response criteria do not consider the depth of organ response, this has been shown to have prognostic utility in newly diagnosed patients. So, we designed this study to evaluate a composite hematologic and organ scoring system that also considers the depth of organ response at 1 to 6 months from initiation of first-line treatment. Methods: We included patients with AL amyloidosis who had at least one major organ involvement (cardiac, renal and/or liver involvement) and who had not started a second line treatment by 6 months from the time of initiating first-line treatment. For each patient, we calculated an organ response score and a hematologic response score at 1, 2, 3, 4, 5, and 6 months from initiation of first-line treatment. A score was assigned for each depth of hematologic response as follows: complete response=0, very good partial response=1, partial response=2, and no response/progressive disease=3). To calculate organ response, a score was assigned to each organ based on the depth of organ response (Muchtar et al. 2018): non-evaluable=0, complete response=1, very good partial response=2, partial response=3, and no response=4. The final organ response score was obtained by calculating the average of the individual involved organ scores. We then calculated the composite hematologic and organ response (HOR) score by adding the organ and hematologic responses at each interval and compared overall survival (OS) between patients with HOR score ≤ 5 (group 1) and those with score > 5 (group 2). Results: The cohort included 730 patients diagnosed with AL amyloidosis between February 10 th, 2006 and July 9 th, 2019. Median age was 63 (IQR: 56-69), and 65% were male. The involved light chain was Lambda in 75% of cases. Cardiac, renal, and liver involvement were found in 81%, 61%, and 17% of patients, respectively. Among all patients, 28% underwent autologous stem cell transplantation during their disease course. The median follow up in the entire cohort was 7.0 (95%CI: 6.4-8.0) years and OS was 3.6 (95%CI: 2.6-4.4) years. At 1 to 4 months, we observed a statistically significant difference in OS between patients with HOR score ≤5 vs. >5. However, there was no difference in OS between the 2 groups at 5 and 6 months. These results are presented in Table 1. Conclusion: A composite hematologic and organ response score that takes into consideration the depth of organ response can discriminate 2 groups of patients with distinct survival outcomes as early as 1 month from treatment initiation and maintains its predictive ability for up to 4 months. The lack of predictive ability beyond 4 months in this study may be due to limited sample size especially in group 2 as more patients achieve deeper responses with time. This approach can provide the basis for early changes in treatment but needs validation in future studies. Figure 1 Figure 1. Disclosures Dispenzieri: Janssen: Consultancy, Research Funding; Takeda: Research Funding; Sorrento Therapeutics: Consultancy; Oncopeptides: Consultancy; Pfizer: Research Funding; Alnylam: Research Funding. Gertz: Ionis Pharmaceuticals: Other: Advisory Board; Akcea Therapeutics, Ambry Genetics, Amgen Inc, Celgene Corporation, Janssen Biotech Inc, Karyopharm Therapeutics, Pfizer Inc (to Institution), Sanofi Genzyme: Honoraria; Aurora Biopharma: Other: Stock option; Akcea Therapeutics, Alnylam Pharmaceuticals Inc, Prothena: Consultancy; AbbVie Inc, Celgene Corporation: Other: Data Safetly & Monitoring. Kapoor: Ichnos Sciences: Research Funding; Karyopharm: Consultancy; Glaxo SmithKline: Research Funding; Pharmacyclics: Consultancy; Amgen: Research Funding; Cellectar: Consultancy; Sanofi: Consultancy; BeiGene: Consultancy; Regeneron Pharmaceuticals: Research Funding; Karyopharm: Research Funding; Sanofi: Research Funding; Takeda: Research Funding; AbbVie: Research Funding. Dingli: GSK: Consultancy; Sanofi: Consultancy; Janssen: Consultancy; Novartis: Research Funding; Apellis: Consultancy; Alexion: Consultancy. Kumar: Oncopeptides: Consultancy; Merck: Research Funding; Antengene: Consultancy, Honoraria; Bluebird Bio: Consultancy; Roche-Genentech: Consultancy, Research Funding; Astra-Zeneca: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Research Funding; Novartis: Research Funding; Carsgen: Research Funding; Tenebio: Research Funding; Celgene: Membership on an entity's Board of Directors or advisory committees, Research Funding; KITE: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; BMS: Consultancy, Research Funding; Abbvie: Consultancy, Membership on an entity's Board of Directors or advisory committees, Research Funding; Beigene: Consultancy; Adaptive: Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Research Funding; Takeda: 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.

AbstractGain of 1q22 at diagnosis portends poorer outcomes in multiple myeloma (MM), but the prognostic significance of acquired 1q22 gain is unknown. We identified 63 MM patients seen at Mayo Clinic from 1/2004 to 12/2019 without 1q22 gain at diagnosis who acquired it during follow up and compared them to 63 control patients who did not acquire 1q22 gain with similar follow up. We also compared outcomes in the acquired 1q22 gain group with outcomes in 126 patients with 1q22 gain present at diagnosis. The incidence of acquired 1q22 gain was 6.1% (median follow‐up 6.8 years); median time to acquisition was 5.0 years (range: 0.7–11.5 years). Abnormalities on baseline fluorescence in situ hybridization (FISH) included trisomies (54%) and monosomy 13 (39%); 16 (25%) had high‐risk (HR) translocations or del(17p). Median progression‐free survival with front line therapy was 29.5 months in patients with acquired 1q22 gain, versus 31.4 months in control patients (p = .34) and 31.2 months in patients with de novo 1q22 gain (p = .04). Median overall survival (OS) from diagnosis was 10.9 years in patients with acquired 1q22 gain, versus 13.0 years in control patients (p = .03) and 6.3 years in patients with de novo 1q22 gain (p = .01). Presence of HR FISH at baseline increased risk of 1q22 gain acquisition. We demonstrate that acquisition of 1q22 gain is a significant molecular event in MM, associated with reduced OS. Among HR patients for whom this clonal evolution is determined, a risk‐adapted approach and/or clinical trial should be considered.

SummaryPatients with asymptomatic/smouldering Waldenström macroglobulinaemia (SWM) have a variable risk of progression to active WM. Our study evaluated 143 patients with SWM consecutively seen between January 1996 and December 2013. With a median [95% confidence interval (CI)] follow‐up of 9·5 [8·1–11·5] years, the cumulative rate of progression was 11% at 1 year, 38% at 3 years and 55% at 5 years. On multivariate analysis, haemoglobin (Hb) ≤123 g/l [risk ratio (RR) 2·08; P = 0·009] and β2‐microglobulin (β2M) ≥2·7 µg/ml (RR 2·0; P = 0·01) were independent predictors of a shorter time‐to‐progression (TTP) to active WM. Patients with myeloid differentiation factor 88 wild type (MYD88WT) genotype (n = 11) demonstrated a trend toward shorter TTP [median (95% CI) 1·7 (0·7–8·7) vs. 4·7 (2·4–7·7) years for the MYD88L265P cohort, n = 42; P = 0·11]. The presence of C‐X‐C chemokine receptor type 4 (CXCR4) mutation (n = 29) did not impact the TTP (median: 3 years for CXCR4WT vs. 5·6 years for CXCR4MUT, P = 0·34). The overall survival (OS) for patients with SWM (median: 18·1 years) was comparable to an age‐, sex‐ and calendar year‐matched USA population (median: 20·3 years, P = 0·502). In conclusion, Hb and β2M at diagnosis represent independent predictors of progression to active WM. Comparable survival of SWM and a matched USA population argues against pre‐emptive intervention in this patient population.

Abstract Multiple myeloma (MM) is a heterogeneous disease that may be evaluated by a broad array of imaging and laboratory techniques to measure disease activity and predict prognosis. Fluorodeoxyglucose (FDG) positron emission tomography/computed tomography (PET/CT) scanning has been shown to be predictive of patient outcomes throughout the disease course. We sought to corroborate these findings by examining the prognostic impact of PET/CT scanning in the posttransplant setting. We retrospectively analyzed PET/CT scans in 229 MM patients receiving an autologous stem cell transplant (ASCT) near day 100, and correlated these findings with time to progression(TTP) and overall survival (OS) to assess the impact of day 100 PET/CT scan findings as an independent prognostic factor. The median OS for the entire cohort was 61.5 months (95% confidence interval [CI], 49-75) and the median TTP was 18.5 months (95% CI, 15.4-21.8). Among patients with abnormal day 100 PET findings (PET+), median TTP was 12.4 months vs 24 months among those with normal PET findings (PET−) (P < .0001). The median OS in the PET+ group was 46 months compared with 99 months in the PET− group (P < .0001). We conclude that an abnormal PET/CT scan near day 100 post-ASCT is predictive of shorter TTP and OS, with prognostic significance retained after adjusting for disease response and other prognostic variables in MM.

AbstractMultiple myeloma (MM) remains an incurable disease despite incorporation of novel agents. Venetoclax, a B‐cell lymphoma 2 (BCL‐2) inhibitor is approved for some hematologic malignancies but not yet for MM, although clinical trials have shown efficacy in patients with MM, particularly those harboring t(11;14). We reviewed the medical records of relapsed and/or refractory MM patients to study the efficacy and safety of venetoclax used outside of clinical trials at Mayo Clinic between December, 2016 and March, 2019. The data cut‐off date was August 06, 2020. We identified 56 patients of whom 42 (75%) harbored t(11;14). The median number of prior therapies was six (range 1–15) and 14% of patients had received ≥10 prior lines of therapy. Fifty‐three (95%) patients were refractory to an immunomodulatory drug and proteasome inhibitor. Venetoclax was used as monotherapy or doublet, in combination with dexamethasone in 55% (n = 31) and a triplet or quadruplet in 45% of patients. No patient experienced tumor lysis syndrome. Overall response rate in 52 evaluable patients was 44%. The median time to best response was 2 months and median duration of response was 13.6 months. The median PFS for the entire cohort was 5.8 (95% CI 4.9–10.3) months and median OS was 28.4 (95% CI 14.6‐not reached) months. The presence of t(11;14) was associated with improved PFS (median 9.7 months vs. 4.2 months, p = 0.019) and OS (median not reached vs. 10.8 9 months, p = 0.015). Venetoclax demonstrates encouraging activity in heavily‐treated patients with relapsed/refractory MM, particularly the t(11;14) patient‐population.

e20016 Background: An elevated serum LDH level is an adverse prognostic factor in NDMM. However, this category includes quantitative serum LDH levels that range from just over the upper limit of normal (ULN) to levels that may be 2 or more-fold higher than the ULN. This binary classification of serum LDH level of “normal versus elevated” fails to discriminate between the different disease biology that exists among NDMM patients with elevated serum LDH levels. Thus, we attempted to further stratify NDMM patients by the level of their serum LDH and determine its impact on OS. Methods: The cohort included patients diagnosed with NDMM from the Mayo Clinic, Rochester from 2003 - 2017 who were treated with novel agent induction therapy and had serum LDH levels measured at the time of diagnosis. The serum LDH levels were stratified into three levels: Normal (LDH < 222 U/L), Elevated (LDH 223-444 U/L), and Very Elevated (LDH >444 U/L or >2x upper limit of normal). Survival analysis was performed using the Kaplan-Meier survival analysis and compared via the log-rank method. Results: The cohort consists of 1,196 NDMM patients with a median age of 65 (22 – 95). R-ISS classification and cytogenetic risk were available for 968 and 970 patients respectively. The median serum LDH level was (162 U/L (3- 1260)) and an elevated LDH was present in 199 patients (17%). The median OS for patients with normal (N = 997; 83%), elevated (N = 170; 13%) and very elevated (N = 29; 3%) LDH levels were 76 months, 57 months and 23 months respectively (P < 0.001). The impact of these different levels of LDH on OS by R-ISS stage and cytogenetic risk is shown in the Table. Conclusions: A very small subset of NDMM patients has very elevated LDH levels that confer an exceptionally poor OS irrespective of R-ISS stage and cytogenetic risk. Future studies elucidating their disease biology responsible for such poor OS outcomes are warranted.[Table: see text]

e20000 Background: In the novel agents’ era, refractoriness to induction in Multiple Myeloma (MM) is relatively rare. This population remain an unmet need and are often excluded from clinical trials. In the current era, chemotherapy-induced stem cell collections are used at Mayo Clinic in “poor responders” to induction, such as patients that progress prior to ASCT or patients with significant disease burden after induction. Methods: This is a retrospective study that includes all MM patients the underwent chemo-mobilization between January 2012 and September 2020 at Mayo Clinic. We compared our cohort to a cohort of 125 matched patients that were transplanted over the same time period and underwent mobilization with G-CSF and “on-demand” plerixafor. We matched the cohorts by level of response by IMWG at pre-transplant evaluation. Results: 125 newly diagnosed MM patients who received novel agents’ induction and had a poor response to induction were mobilized using IV intermediate-dose cyclophosphamide (83%) or VDT-PACE (17%) plus G-CSF and “on-demand” plerixafor. The median PFS and OS of the chemo-mobilized cohort were 16 months (95% CI 11-20) and 47 months (95% CI 37-71), respectively. Patients receiving chemo-mobilization had higher stem cell yields than the growth factor only cohort (median 9.88X106 cells/kg versus median 8.77X106 cells/kg, respectively (P<0.001)). The safety profile of chemo-mobilization was favorable, with no difference between the two groups in length of hospitalization during ASCT (P=0.95), days to neutrophil or platelet engraftment, and risk of bacteremia (P=0.38). 29% of the chemo-mobilized cohort and 66% of the matched cohort required plerixafor for adequate mobilization (P<0.001). Conclusions: Chemo-mobilization enhances stem cell collection in MM patients with a suboptimal response to induction and reduces the need for plerixafor without adversely impacting the post-transplant clinical course. [Table: see text]