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Intermittent hypoxia exposures are commonly used in physiology and many investigators use chamber systems to perform these studies. Because of the variety of chamber systems and protocols used, it is important to understand the sources of variability in intermittent hypoxia experiments that can impact reproducibility. We demonstrate sources of variability that come from the animal model, the intermittent hypoxia protocol, and the chamber system that can impact reproducibility.

In patients with Down syndrome (DS), CHD is the leading cause of death 20 yr old. Men with DS live longer than women. It is unknown if sex differences are present in cardiovascular disease and dysregulation in DS across the lifespan. We observed higher risk of hypertension, ischemic heart disease, and cerebrovascular disease in females and a higher risk of CHD in males with DS.

Multiple myeloma pathogenesis is driven by the MYC oncoprotein, its dimerization with MAX, and the binding of this heterodimer to E-Boxes in the vicinity of target genes. The systemic utility of potent small molecule inhibitors of MYC-MAX dimerization was limited by poor bioavailability, rapid metabolism, and inadequate target site penetration. We hypothesized that new lipid-based MYC-MAX dimerization inhibitor prodrugs delivered via integrin-targeted nanoparticles (NP) would overcome prior shortcomings of MYC inhibitor approaches and prolong survival in a mouse model of cancer. An Sn 2 lipase-labile prodrug inhibitor of MYC-MAX dimerization (MI1-PD) was developed which decreased cell proliferation and induced apoptosis in cultured multiple myeloma cell lines alone (P < 0.05) and when incorporated into integrin-targeted lipid-encapsulated NPs (P < 0.05). Binding and efficacy of NPs closely correlated with integrin expression of the target multiple myeloma cells. Using a KaLwRij metastatic multiple myeloma mouse model, VLA-4–targeted NPs (20 nm and 200 nm) incorporating MI1-PD (D) NPs conferred significant survival benefits compared with respective NP controls, targeted (T) no-drug (ND), and untargeted (NT) control NPs (T/D 200: 46 days vs. NT/ND: 28 days, P < 0.05 and T/D 20: 52 days vs. NT/ND: 29 days, P = 0.001). The smaller particles performed better of the two sizes. Neither MI1 nor MI1-PD provided survival benefit when administered systemically as free compounds. These results demonstrate for the first time that a small molecule inhibitor of the MYC transcription factor can be an effective anticancer agent when delivered using a targeted nanotherapy approach. Mol Cancer Ther; 14(6); 1286–94. ©2015 AACR.

Supplemental Figures 1-4. Supplemental figure 1: Representative schematic of lipid encapsulated nanoparticle design. Supplemental figure 2: The pharmacokinetics nanoparticles Supplemental figure 3:Biodistribution of the Nanoparticles Supplemental figure 4: Kalwrij mice survival data

Supplementary Information

Supplementary Table S1. Summary statistics of the estimated slopes and turning points for the model fitting of the six cohorts from the three trials. Supplementary Table S2. Information on the number of data points in the pre-treatment phase, phase during administration of therapy, and posttreatment phase. Supplementary Table S3. Summary statistics of slopes and turning points for the treatment response data of the VISTA, MMY-2001, and APEX trials. Supplementary Table S4. Dependence of MM stage, prior administration of steroids, and the best-fitting model. Supplementary Table S5. Counts of death for single-phasic and 2-phasic patients as well as different sub-cohorts based on modeling parameters in the VISTA MP and VISTA VMP cohort during treatment. Supplementary Table S6. Summary statistics of the day differences between scheduled and actual visit dates for during-treatment response data for the VISTA MP and VISTA VMP cohort. Supplementary Table S7. Parameter values used for the hybrid mathematical model for all three cohorts.

Supplementary Figure S1. Demonstration of exponential curves and corresponding linear curves after log-transforming the original data. Supplementary Figure S2. Baseline values for the analysis of disease dynamics during treatment. Supplementary Figure S3. Histograms of the days from treatment cessation until rebound for patients in the VISTA and APEX trials when defining rebound as any value {greater than or equal to} 20% pre-treatment baseline. Supplementary Figure S4. Histograms of the days from treatment cessation until rebound for patients in the VISTA and APEX trials when defining rebound as any value {greater than or equal to} pre-treatment baseline. Supplementary Figure S5. Histograms of the days from treatment cessation until rebound for patients in the VISTA MP and VISTA VMP cohorts when defining rebound as any value {greater than or equal to} 120% pre-treatment baseline. Supplementary Figure S6. Histogram of the deviation between scheduled visit and real visit dates during the trial. Supplementary Figure S7. The predictions of the differentiation hierarchy model of MM. Supplementary Figure S8. Nine representative examples of predictions of the clonal evolution model of MM. Supplementary Figure S9. Early M-protein rebound for the refractory patients in the VISTA and APEX trials.

Purpose: Since the pioneering work of Salmon and Durie, quantitative measures of tumor burden in multiple myeloma have been used to make clinical predictions and model tumor growth. However, such quantitative analyses have not yet been performed on large datasets from trials using modern chemotherapy regimens.Experimental Design: We analyzed a large set of tumor response data from three randomized controlled trials of bortezomib-based chemotherapy regimens (total sample size n = 1,469 patients) to establish and validate a novel mathematical model of multiple myeloma cell dynamics.Results: Treatment dynamics in newly diagnosed patients were most consistent with a model postulating two tumor cell subpopulations, "progenitor cells" and "differentiated cells." Differential treatment responses were observed with significant tumoricidal effects on differentiated cells and less clear effects on progenitor cells. We validated this model using a second trial of newly diagnosed patients and a third trial of refractory patients. When applying our model to data of relapsed patients, we found that a hybrid model incorporating both a differentiation hierarchy and clonal evolution best explains the response patterns.Conclusions: The clinical data, together with mathematical modeling, suggest that bortezomib-based therapy exerts a selection pressure on myeloma cells that can shape the disease phenotype, thereby generating further inter-patient variability. This model may be a useful tool for improving our understanding of disease biology and the response to chemotherapy regimens. Clin Cancer Res; 22(16); 4206–14. ©2016 AACR.

Diagnosing the cause of hypoxemia and dyspnea can be complicated in complex patients with multiple comorbidities. This “Case Study in Physiology” describes an man with obesity admitted to the hospital for relapse of acute lymphoblastic leukemia, who experienced progressive hypoxemia, shortness of breath, and dyspnea on exertion during his hospitalization. After initial empirical treatment with diuresis and antibiotics failed to improve his symptoms and because an arterial blood gas measurement was not readily available, we applied a novel, recently described physiological method to estimate the arterial partial pressure of oxygen from the peripheral saturation measurement and calculate the alveolar-arterial oxygen difference to discern the source of his hypoxemia and dyspnea. Using basic physiological principles, we describe how hypoventilation, anemia, and the use of a β blocker and furosemide, collaborated to create a “perfect storm” in this patient that impaired oxygen delivery and limited utilization. This case illustrates the application of innovative physiology methodology in medicine and provides a strong rationale for continuing to integrate physiology education in medical education. NEW & NOTEWORTHY Discerning the cause of dyspnea and hypoxemia in complex patients can be difficult. We describe the “real world” application of an innovative methodology to untangle the underlying physiology in a patient with multiple comorbidities. This case further demonstrates the importance of applying physiology to interrogate the underlying cause of a patient’s symptoms when treatment based on probability fails.

Hematopoietic stem cell transplant (HSCT) is a potentially curative treatment for hematopoietic malignancies, complicated by decreased performance status and quality of life. Exercise therapy improves outcomes in HSCT, but several barriers have prevented exercise from becoming routine clinical practice. Based on existing data that wearable technologies facilitate exercise participation in other sedentary and chronic illness populations, we propose the novel hypothesis that wearable technologies are a valuable tool in transcending barriers and developing exercise therapy programs for HSCT patients.

Venetoclax is a highly selective B-cell lymphoma-2 (BCL-2) inhibitor, which, combined with a DNA hypomethylating agent or low dose cytarabine, results in high rates of initial responses in patients with acute myeloid leukemia (AML). However, the disease relapses in most patients. Mechanisms of resistance to venetoclax-based therapy include TP53 gene mutations or inactivation of p53 protein, activating kinase mutations such as FLT3 and RAS, and upregulation of other BCL-2 family apoptotic proteins. Current clinical trials are exploring strategies such as doublet or triplet regimens incorporating a p53 activator, an anti-CD47 antibody, or other novel agents that target genes and proteins responsible for resistance to venetoclax. Further studies should focus on identifying predictive biomarkers of response to venetoclax-based therapy and incorporating immunotherapeutic approaches such as checkpoint inhibitors, bispecific antibodies, antibody-drug conjugates, and CAR T-cell therapy to improve outcomes for patients with AML.

Persons of African ancestry (AA) have a twofold higher risk for multiple myeloma (MM) compared with persons of European ancestry (EA). Genome-wide association studies (GWASs) support a genetic contribution to MM etiology in individuals of EA. Little is known about genetic risk factors for MM in individuals of AA. We performed a meta-analysis of 2 GWASs of MM in 1813 cases and 8871 controls and conducted an admixture mapping scan to identify risk alleles. We fine-mapped the 23 known susceptibility loci to find markers that could better capture MM risk in individuals of AA and constructed a polygenic risk score (PRS) to assess the aggregated effect of known MM risk alleles. In GWAS meta-analysis, we identified 2 suggestive novel loci located at 9p24.3 and 9p13.1 at P < 1 × 10−6; however, no genome-wide significant association was noted. In admixture mapping, we observed a genome-wide significant inverse association between local AA at 2p24.1-23.1 and MM risk in AA individuals. Of the 23 known EA risk variants, 20 showed directional consistency, and 9 replicated at P < .05 in AA individuals. In 8 regions, we identified markers that better capture MM risk in persons with AA. AA individuals with a PRS in the top 10% had a 1.82-fold (95% confidence interval, 1.56-2.11) increased MM risk compared with those with average risk (25%-75%). The strongest functional association was between the risk allele for variant rs56219066 at 5q15 and lower ELL2 expression (P = 5.1 × 10−12). Our study shows that common genetic variation contributes to MM risk in individuals with AA.

The orphan small nucleolar RNA (snoRNA) ACA11 is overexpressed as a result of the t(4;14) chromosomal translocation in multiple myeloma (MM), increases reactive oxygen species, and drives cell proliferation. Like other snoRNAs, ACA11 is predominantly localized to a sub‐nuclear organelle, the nucleolus. We hypothesized that increased ACA11 expression would increase ribosome biogenesis and protein synthesis. We found that ACA11 overexpression in MM cells increased nucleolar area and number as well as argyrophilic nuclear organizing regions (AgNORs). Supporting these data, samples from t(4;14)‐positive patients had higher AgNORs scores than t(4;14)‐negative samples. ACA11 also upregulated ribosome production, pre‐47S rRNA synthesis, and protein synthesis in a ROS‐dependent manner. Lastly, ACA11 overexpression enhanced the response to proteasome inhibitor in MM cells, while no effect was found in response to high doses of melphalan. Together, these data demonstrate that ACA11 stimulates ribosome biogenesis and influences responses to chemotherapy. ACA11 may be a useful target to individualize the treatment for t(4;14)‐positive myeloma patients.

Introduction The clinical application of the Revised International Staging System (R-ISS) for multiple myeloma may be limited by heterogeneity in clinical interphase fluorescent in situ hybridization (FISH) practices for detecting chromosomal abnormalities (CAs). Next generation sequencing (NGS)-based FISH (Seq-FISH) has demonstrated improved sensitivity and similar specificity relative to clinical FISH, and provides a standardized, single-pass method for identifying high-risk CAs. To date, calculating R-ISS stage using Seq-FISH (R-ISS-NGS) has not been validated. Patients and Methods We identified 672 patients with sufficient data to calculate R-ISS-NGS from the Multiple Myeloma Research Foundation (MMRF) CoMMpass Study. R-ISS-NGS was calculated from original ISS stage, lactate dehydrogenase, and CAs detected by Seq-FISH. Endpoints included overall survival and progression-free survival. We conducted multivariate analyses controlling for age and gender in order to compare outcomes across stages I to III of both the original ISS and R-ISS-NGS. Results The median follow-up was 24 months. The R-ISS-NGS resulted in significant redistribution of patients into stage II, relative to the original ISS. With respect to stage I, R-ISS-NGS stages II and III of were associated with worse progression-free survival or overall survival, more so than the staging schema of the ISS, thus validating the use of Seq-FISH in staging. Conclusion Using CAs detected by Seq-FISH and data from the CoMMpass study, we validated the R-ISS with a large, generalizable cohort. This study validates the substitution of Seq-FISH for clinical FISH, especially in large registry studies. Additionally, use of the validated R-ISS-NGS will strengthen outcomes research generated from the CoMMpass study.

Abnormal serum immunoglobulin (Ig) free light chains (FLC) are established biomarkers of early disease in multiple B-cell lymphoid malignancies, including chronic lymphocytic leukemia (CLL). Heavy chains have also been shown to be biomarkers in plasma cell disorders. An unanswered question is whether these Ig biomarkers are heritable, i.e., influenced by germline factors. CLL is heritable but highly heterogeneous. Heritable biomarkers could elucidate steps of disease pathogenesis that are affected by germline factors, and may help partition heterogeneity and identify genetic pleiotropies across malignancies. Relatives in CLL pedigrees present an opportunity to identify heritable biomarkers. We compared FLCs and heavy chains between relatives in 23 high-risk CLL pedigrees and population controls. Elevated IgM (eIgM) and abnormal FLC (aFLC) ratio was significantly increased in relatives, suggesting that these Ig biomarkers are heritable and could offer risk stratification in pedigree relatives. Within high-risk CLL pedigrees, B-cell lymphoid malignancies were five times more prevalent in close relatives of individuals with eIgM, prostate cancer was three times more prevalent in relatives of individuals with aFLC, and monoclonal B-cell lymphocytosis increased surrounding individuals with normal Ig levels. These different clustering patterns suggest Ig biomarkers have the potential to partition genetic heterogeneity in CLL and provide insight into distinct heritable pleiotropies associated with CLL.

8006 Background: Elranatamab (PF-06863135) is a humanized bispecific antibody that targets both BCMA-expressing MM cells and CD3-expressing T cells. MagnetisMM-3 (NCT04649359) is an open-label, multicenter, non-randomized, phase 2 study to evaluate the safety and efficacy of elranatamab monotherapy in pts with R/R MM. Initial safety results are presented. Methods: MagnetisMM-3 enrolled pts who are refractory to at least 1 proteasome inhibitor, 1 immunomodulatory drug, and 1 anti-CD38 antibody. Pts were assigned to 1 of 2 independent, parallel cohorts: those naïve to BCMA-directed therapies (Cohort A) and those with previous exposure to BCMA-directed antibody-drug conjugates or CAR-T cells (Cohort B). Pts received subcutaneous elranatamab 76 mg QW on a 28-d cycle with a 2-step-up priming dose regimen administered during the first week. Dose modifications were permitted for toxicity. Treatment-emergent adverse events (TEAEs) were graded by CTCAE (v5.0), and cytokine release syndrome (CRS) and immune effector cell-associated neurotoxicity syndrome (ICANS) by ASTCT criteria. Results: As of the data cutoff on Dec 31, 2021, 60 pts in Cohort A had received ≥1 dose of elranatamab; the last pt’s first dose was ̃2 months prior to the cutoff. Median age was 69.0 y (range, 44−89), 48.3% were male, 63.3% were white, 18.3% were Asian and 11.7% were Black/African American. At baseline, 60.0% of pts had an ECOG performance status 1−2 and pts had received a median of 5 (range, 2−12) prior therapies. Median duration of elranatamab treatment was 9.57 wks (range, 0.1−46.1); median relative dose intensity was 87.4% (range, 23.1−101.4). TEAEs were reported in 100% (Grade [G] 3/4, 75.0%) of pts. Most common (≥30%) hematologic TEAEs were neutropenia (36.7% [G3/4, 35.0%]), anemia (36.7% [G3/4, 30.0%]) and thrombocytopenia (30.0% [G3/4, 21.7%]). Among pts who received the 2-step-up priming regimen (n = 56), CRS and ICANS, respectively, were reported in 58.9% (G3/4, 0%) and 3.6% (G3/4: 0%); of those pts, 57.6% (n = 19/33) and 100% (n = 2/2) received tocilizumab and/or steroids. Most common (≥30%) non-hematologic TEAE, other than CRS/ICANS, was fatigue (31.7% [G3/4, 3.3%]). Infections were reported in 46.7% (G3/4: 18.3%) of pts; most frequently reported were upper respiratory tract infections (11.7% [G3/4: 0%]). Discontinuations due to adverse events were reported in 5.0% of pts. No pts permanently discontinued treatment due to CRS or ICANS. There were 10 deaths; causes were MM progression (n = 8), septic shock (n = 1) and unknown (n = 1). Data will be updated at the time of presentation to include ̃90 pts. Conclusions: Preliminary results of MagnetisMM-3 in pts with R/R MM and no prior BCMA-targeted treatment suggest that 76 mg QW elranatamab with a 2-step-up priming regimen is well tolerated, with no G ≥3 CRS or ICANS observed. Clinical trial information: NCT04649359.

8014 Background: Elranatamab (PF-06863135) is a bispecific molecule that activates and redirects the T-cell mediated immune response against multiple myeloma (MM), a plasma cell dyscrasia characterized by expression of B-cell maturation antigen (BCMA). MagnetisMM-1 (NCT03269136), the ongoing Phase 1 first-in-human study for elranatamab, was designed to characterize safety, pharmacokinetics (PK), pharmacodynamics, and efficacy for patients (pts) with relapsed or refractory MM. Methods: Elranatamab was given subcutaneously (SC) at doses from 80 to 1000µg/kg either weekly or every 2 weeks (Q2W). Treatment-emergent adverse events (TEAEs) were graded by Common Terminology Criteria for Adverse Events (v4.03) and cytokine release syndrome (CRS) by American Society for Transplantation and Cellular Therapy criteria. PK, cytokine and soluble BCMA profiling, and lymphocyte subset analyses were performed. Response was assessed by International Myeloma Working Group (IMWG) criteria. Minimal residual disease (MRD) was assessed by next generation sequencing at a sensitivity of 1×10-5 in accordance with IMWG criteria. Results: A total of 55 pts received single-agent elranatamab SC at a dose ≥215μg/kg as of 1-Nov-2021. Median age was 64 (range 42-80) years, and 27% of pts were Black/African American or Asian. Median number of prior regimens was 6 (range 2-15), 91% were triple-class refractory, 56% had prior stem cell transplantation, 27% had high cytogenetic risk, and 22% received prior BCMA-targeted therapy. The most common TEAEs regardless of causality included CRS, neutropenia, anemia, injection site reaction, and lymphopenia. With pre-medication and a single priming dose (600µg/kg or 44mg), the overall incidence of CRS at the recommended dose (1000µg/kg or 76mg) was 67% and limited to Grade 1 (33%) or Grade 2 (33%), with no events Grade 3 or higher. Exposure was dose dependent and Q2W dosing achieved exposure associated with anti-myeloma efficacy. Cytokine increases occurred with the first dose and were reduced by pre-medication. Soluble BCMA decreased with disease response, elranatamab therapy was associated with increased peripheral T cell proliferation, and median time to response was 36 days (range 7-73). With a median follow-up of 8.1 months (range 0.3-21) and including only IMWG confirmed responses, 31% of pts achieved complete response or better and the overall response rate was 64% (95% CI 50-75%). For responders (n = 35), median duration of response was not yet reached, but the probability of being event-free at 6 months was 91% (95% CI 73-97%). Single-agent elranatamab induces durable clinical and molecular responses, and updated data including MRD assessment will be presented. Conclusions: Elranatamab shows a manageable safety profile and achieves durable clinical and molecular responses for pts with relapsed or refractory MM. Clinical trial information: NCT03269136.

Objectives Elranatamab (PF-06863135) is a humanized bispecific monoclonal antibody (IgG2a) that targets BCMA, a member of the tumor necrosis factor receptor superfamily expressed in multiple myeloma, and CD3 on T cells. We reported results for intravenous (IV) dosing (Raje et al. Blood. 2019;134(S1):1869) and now update for subcutaneous (SC) dosing from the ongoing Phase 1 study (MagnetisMM-1; NCT03269136). Materials and methods Patients received elranatamab at 80, 130, 215, 360, 600, and 1000 μg/kg SC weekly. A modified toxicity probability interval method was used for escalation, with monitoring for dose-limiting toxicity (DLT) to end of the first cycle. Treatment-emergent adverse events (TEAEs) were graded by Common Terminology Criteria for Adverse Events (v4.03), and cytokine release syndrome (CRS) by American Society for Transplantation and Cellular Therapy criteria (Lee et al. Biol Blood Marrow Transplant. 2019;25:625). Response was assessed by International Myeloma Working Group criteria. Pharmacokinetics, cytokine profiling, and T cell immunophenotyping were performed. Results 30 patients had received elranatamab as of 4-Feb-2021 at 80 (n = 6), 130 (n = 4), 215 (n = 4), 360 (n = 4), 600 (n = 6), or 1000 (n = 6) μg/kg SC weekly. Patients had a median of 8 prior treatments; 87% had triple refractory disease, 97% had prior anti-CD38 therapy, and 23% (7 patients) had prior BCMA-directed antibody drug conjugate (6 of 7 patients) or chimeric antigen receptor T cell therapy (3 of 7 patients). The most common all causality TEAEs included lymphopenia (n = 25, 83%; 20% G3, 63% G4), CRS (n = 22, 73%; 57% G1, 17% G2, none ≥G3), anemia (n = 18, 60%; 50% G3, 0% G4), thrombocytopenia (n = 16, 53%; 17% G3, 20% G4), neutropenia (n = 16, 53%; 23% G3, 30% G4), and injection site reaction (n = 15, 50%; 43% G1, 7% G2, none ≥G3). Both CRS and immune effector cell-associated neurotoxicity syndrome (n = 6, 20%) were limited to ≤G2 with median durations of 3 and 2.5 days, respectively. No DLT was observed. Exposure increased with dose, and Tmax ranged from 3–7 days. Cytokine increases occurred with the first dose, and increased T-cell proliferation was observed in peripheral blood. The overall response rate (ORR) for doses ≥215 μg/kg was 70% (n = 14/20) including partial response (PR; n = 1), very good PR (VGPR; n = 7), complete response (CR; n = 1), and stringent CR (sCR; n = 5). Median time to response was 22 days, and 3 of 4 patients (75%) with prior BCMA-directed therapy achieved response (VGPR, n = 2 and sCR, n = 1). Updated data, including duration of response, will be presented. Discussion Elranatamab demonstrated a manageable safety profile and, across the efficacious dose range (≥215 μg/kg), achieved ORR of 70% with CR/sCR rate of 30%, including responses after prior BCMA-directed therapy. Conclusion These results demonstrate the safety and efficacy of elranatamab in this relapsed/refractory population and support ongoing development of elranatamab for patients with multiple myeloma, both as monotherapy and in combination with standard or novel therapies.

Background Patients (pts) with relapsed/triple-class refractory (R/R; refractory to a proteasome inhibitor, immunomodulatory drug or anti-CD38 antibody) multiple myeloma (MM) have limited treatment options. A need remains for novel combination therapies with manageable toxicity and non-cross-resistant mechanisms of action. B-cell maturation antigen (BCMA) is expressed in most MM pt tumors. SEA-BCMA is an investigational, humanized, nonfucosylated IgG1 monoclonal anti-BCMA antibody. Proposed mechanisms of action of SEA-BCMA include blocking of BCMA-mediated pro-survival and proliferative signaling, mediating antibody-dependent cellular phagocytosis, and displaying enhanced antibody-dependent cellular cytotoxicity. Preclinical data demonstrate promising antitumor activity and versatile combinability. Here, we present preliminary data from the first-in-human Phase 1 clinical trial. Methods SGNBCMA-001 (NCT03582033) is an ongoing phase 1, open-label, multicenter, dose-escalation and expansion study to evaluate the safety, tolerability and antitumor activity of SEA-BCMA in adults with R/R MM not previously exposed to any other BCMA-directed therapy. Part A tested monotherapy safety and tolerability with dose escalation (100-1600 mg flat dosing once every 2 weeks [Q2W] by intravenous infusion), and dose expansion at the highest tolerated dose. Parts B and C aim to optimize efficacy by testing intensified dosing (Part B; weekly [Q1W] induction dosing of SEA BCMA for 8 weeks is followed by Q2W maintenance dosing) and dexamethasone (DEX) combination therapy (Part C) in pts who have received ≥3 prior lines of therapy for MM and are triple-class refractory. Responses are assessed per the 2016 International Myeloma Working Group criteria. Results As of June 15, 2021, Part A completed enrollment. A total of 55 pts received SEA-BCMA (see Table 1 for pt characteristics). SEA-BCMA was generally well tolerated, and the maximum tolerated dose was not reached in the 5 dose levels tested in Part A (100, 200, 400, 800, or 1600 mg Q2W; n=2, 2, 2, 7, and 7, respectively). At 800 mg, 1 of 7 pts reported a Grade 3 infusion-related reaction (IRR), which met dose-limiting toxicity (DLT) criteria by lasting >24 hours despite supportive care. This constituted the single DLT observed during dose escalation. Subsequently, dose expansion (n=15) proceeded at 1600 mg Q2W. The most common treatment-emergent adverse events (TEAEs) observed with 1600 mg Q2W (n=22) were fatigue (32%), pyrexia (23%), IRR (23%), and hypertension (23%) for non-hematological events, and anemia (14%) for hematologic events. The most common ≥Grade 3 TEAEs with 1600 mg Q2W were anemia and syncope (9% each). Following a safety monitoring review, premedication with acetaminophen + antihistamine was introduced to mitigate IRRs in expansion cohorts. Parts B and C completed parallel safety run-ins (n=6 each) at the 1600 mg dose with no DLTs observed and with similar tolerability. Pharmacokinetic (PK) analyses indicate serum SEA-BCMA exposures increased proportionally with increasing dose with a half-life of approximately 10 days. Preliminary analyses suggest the PK profile of SEA-BCMA in combination therapy with DEX (n=5) is comparable to monotherapy and is unaltered with a change in schedule from Q2W to Q1W. Three of 22 pts who received 1600 mg SEA-BCMA Q2W monotherapy (Part A) achieved a confirmed objective response (OR; OR rate: 14% [95% confidence interval: 2.91, 34.91]; 2 partial responses [PR], 1 very good PR [VGPR]). To date, 3 pts remain on treatment (2 PRs and 1 stable disease). The median duration of treatment was 12 weeks (Figure 1; range 4-88). In Parts B and C, 2 of 8 (2 PR) and 2 of 12 (1 VGPR, 1 PR) pts reported a confirmed OR; 3 of the 4 responding pts remain on treatment in cycle 7, 8, and 9, respectively. Conclusions Preliminary results for SGNBCMA-001 suggest a favorable safety profile and combination potential. SEA-BCMA also showed encouraging duration on treatment and initial antitumor activity in a heavily pre-treated late-line R/R MM pt population. Expansion cohorts testing intensified SEA-BCMA dosing and the addition of DEX are underway to further assess the safety, tolerability, and estimate of SEA-BCMA activity in the context of these treatment approaches. An additional expansion cohort (Part D), testing the combination of SEA-BCMA with pomalidomide and DEX in pts who have received ≥2 prior lines of therapy, is now enrolling. Figure 1 Figure 1. Disclosures Hoffman: BMS, Celgene: Honoraria. Lipe: Seagen Inc.: Research Funding; BMS: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; sanofi: Consultancy; GlaxoSmithKline: Consultancy; amgen: Research Funding; Cellectar: Research Funding; Karyopharm: Research Funding; Harpoon: Research Funding. Melear: Astrazeneca: Speakers Bureau; TG Therapeutics: Speakers Bureau; Janssen: Speakers Bureau. Liedtke: Pfizer: Honoraria; Janssen Pharmaceuticals: Membership on an entity's Board of Directors or advisory committees; Bristol Myers Squibb: Membership on an entity's Board of Directors or advisory committees; Alnylam: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Kura Oncology: Membership on an entity's Board of Directors or advisory committees; Caelum: Membership on an entity's Board of Directors or advisory committees, Other: Clinical Trial Funding; Kite: Membership on an entity's Board of Directors or advisory committees; Karyopharm: 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; Oncopeptides: Membership on an entity's Board of Directors or advisory committees; GlaxoSmithKline: Membership on an entity's Board of Directors or advisory committees. Niesvizky: Takeda: Consultancy, Research Funding; Janssen: Consultancy, Research Funding; GSK: Consultancy, Research Funding; BMS: Consultancy, Research Funding; Karyopharm: Consultancy, Research Funding. Tomasson: Pfizer, Inc.: Research Funding; Rafael Pharmaceuticals: Research Funding; syros Pharmaceuticals: Research Funding; Janssen R&D: Research Funding; Seagen, Inc.: Research Funding. Yasenchak: Seagen Inc.: Research Funding. Green: Seagen Inc.: Research Funding; bristol myers squibb: Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding; Cellectar Biosciences: Research Funding; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen Biotech: Membership on an entity's Board of Directors or advisory committees, Research Funding; Juno Therapeutics: Patents & Royalties, Research Funding; Legend Biotech: Consultancy; Neoleukin Therapeutics: 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; SpringWorks Therapeutics: Research Funding. Li: Seagen Inc.: Current Employment, Current equity holder in publicly-traded company. Wang: Seagen Inc.: Current Employment, Current equity holder in publicly-traded company. Ho: Seagen Inc.: Current Employment, Current equity holder in publicly-traded company.

Introduction: MagnetisMM-1 (NCT03269136) is a Phase 1 study of elranatamab (PF-06863135), a humanized bispecific molecule that targets BCMA expressed on multiple myeloma (MM) and engages CD3 on T cells, for patients (pts) with relapsed or refractory MM (RRMM). We report results from the subcutaneous (SC) cohorts: dose escalation (Part 1), monotherapy with priming (Part 1.1), lenalidomide (LEN) combination (Part 1C), pomalidomide (POM) combination (Part 1D), and monotherapy expansion with priming (Part 2A). Methods: In Part 1, pts received elranatamab at 80, 130, 215, 360, 600, and 1000μg/kg weekly guided by a modified toxicity probability interval method. For monotherapy at the recommended Phase 2 dose (RP2D; Parts 1.1 and 2A), a single priming dose (600μg/kg or equivalent fixed dose of 44mg) was followed one week later by the full dose (1000μg/kg or equivalent fixed dose of 76mg) weekly (Q1W) or every 2 weeks (Q2W) thereafter. For LEN or POM combination therapy, a single priming dose (32mg) was followed one week later by the full dose (44mg) Q1W thereafter in combination with either LEN (25mg) or POM (4mg) on Days 1 to 21 of a 28-day cycle. Dose-limiting toxicity (DLT) was monitored to the end of the first cycle. Treatment-emergent adverse events (TEAEs) were graded by Common Terminology Criteria for Adverse Events (v4.03), and cytokine release syndrome (CRS) by American Society for Transplantation and Cellular Therapy criteria. Pharmacokinetics, cytokine profiling, and T cell immunophenotyping were performed. Response was assessed by International Myeloma Working Group (IMWG) criteria. Minimal residual disease (MRD) was assessed by next generation sequencing at a sensitivity of 1×10 -5, in accordance with IMWG criteria. Results: 58 pts received elranatamab SC as a single agent (n=50) or in combination with either LEN (n=4) or POM (n=4) as of 4-Feb-2021. Pts had a median (range) age of 64 (32-86) years, and 26% were Black/African American or Asian. Pts had a median of 6 prior regimens, 98% had triple-class relapsed/refractory disease, 45% had prior high-dose chemotherapy with stem cell transplantation, and 22% had prior BCMA-targeted therapy. The most common all causality TEAEs included CRS (n=48, 83%; none higher than G2), lymphopenia (n=37, 64%; 12% G3, 52% G4), neutropenia (n=37, 64%; 31% G3, 29% G4), anemia (n=32, 55%; 38% G3, 0% G4), injection site reaction (n=31, 53%; none higher than G2), and thrombocytopenia (n=30, 52%; 14% G3, 17% G4). At the RP2D of 1000μg/kg, median duration of CRS decreased by 50% from 4 days to 2 days with priming. Two of 58 pts had DLT including G4 thrombocytopenia (Part 1.1) and G4 neutropenia (POM). Exposure increased with dose, cytokine increases occurred with the first dose, and increased T-cell proliferation was observed in peripheral blood. Median duration of follow-up was 7.5, 2.3, and 1.9 months for the dose escalation, priming, and LEN/POM combination cohorts, respectively. For pts treated across the efficacious dose range (215-1000μg/kg) in Part 1, confirmed overall response rate (ORR) was 70% (14/20) with complete response (CR)/stringent CR (sCR) rate of 30% (6/20). For the 14 pts with confirmed responses, median duration of response had not yet been reached; the probability (95% CI) of responders being event free at 6 months was 92.3% (56.7-98.9). Confirmed ORR at the RP2D was 83% (5/6). Responses in this RRMM population included sCR (n=5), CR (n=1), very good partial response (VGPR; n=7), and partial response (n=1). Median time to response was 22 days. Importantly, 100% (4/4) of evaluable pts with baseline dominant sequence and on-treatment sample at CR/sCR achieved MRD negativity at 1×10 -5 by IMWG criteria, and 75% (3/4) of pts with prior BCMA-targeted therapy achieved response (1 sCR, 2 VGPR). Updated efficacy, safety, and MRD results will be presented for SC parts of the study. Conclusions: Elranatamab as a single agent, administered either Q1W or Q2W, had a manageable safety profile for pts with RRMM. Across the efficacious dose range, elranatamab achieved confirmed ORR of 70% and CR/sCR rate of 30%, with confirmed ORR of 83% at the RP2D. Importantly, elranatamab induces deep and durable clinical responses in RRMM pts with and without prior BCMA-targeted therapy and 100% MRD negativity in MRD evaluable pts. These results, along with emerging combination data, support continued development of elranatamab as a single agent and in combination with standard therapies for MM. Disclosures Sebag: Takeda: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Novartis: Consultancy, Honoraria; Karyopharm Therapeutics: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; Janssen: Research Funding; Bristol Myers-Squibb: Consultancy, Honoraria. Raje: Celgene, Amgen, Bluebird Bio, Janssen, Caribou, and BMS: Other. Bahlis: GlaxoSmithKline: Consultancy, Honoraria; Amgen: Consultancy, Honoraria; Sanofi: Consultancy, Honoraria; BMS/Celgene: Consultancy, Honoraria; Pfizer: Consultancy, Honoraria; Genentech: Consultancy; Janssen: Consultancy, Honoraria; Takeda: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria; Karyopharm: Consultancy, Honoraria. Dholaria: Pfizer: Research Funding; Poseida: Research Funding; Angiocrine: Research Funding; MEI: Research Funding; Jazz: Speakers Bureau; Takeda: Research Funding; Janssen: Research Funding; Celgene: Speakers Bureau. Solh: Partner Therapeutics: Research Funding; Jazz Pharmaceuticals: Consultancy; BMS: Consultancy; ADCT Therapeutics: Consultancy, Research Funding. Levy: Bristol Myers Squibb: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Amgen Inc.: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; AbbVie: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; AstraZeneca: Consultancy, Honoraria, Speakers Bureau; Beigene: Consultancy, Honoraria, Speakers Bureau; Gilead Sciences, Inc.: Consultancy, Honoraria, Speakers Bureau; Janssen Pharmaceuticals: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Jazz Pharmaceuticals: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Morphosys: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Seattle Genetics: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; Takeda: Consultancy, Honoraria, Other: Promotional speaker, Speakers Bureau; TG Therapeutics: Consultancy, Honoraria, Speakers Bureau; Dova: Consultancy, Other: Promotional speaker; Epizyme: Consultancy, Other: Promotional speaker; Novartis: Consultancy, Other: Promotional speaker; GSK: Consultancy, Other: Promotional speaker. Tomasson: Pfizer, Inc.: Research Funding; Rafael Pharmaceuticals: Research Funding; syros Pharmaceuticals: Research Funding; Janssen R&D: Research Funding; Seagen, Inc.: Research Funding. Dube: Pfizer: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Damore: Pfizer: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Lon: Pfizer: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Basu: Pfizer: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Skoura: Pfizer: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Chan: Pfizer: Current holder of individual stocks in a privately-held company, Current holder of stock options in a privately-held company. Trudel: Amgen: Honoraria, Research Funding; BMS/Celgene: Consultancy, Honoraria, Research Funding; GlaxoSmithKline: Consultancy, Honoraria, Research Funding; Roche: Consultancy; Janssen: Honoraria, Research Funding; Sanofi: Honoraria; Pfizer: Honoraria, Research Funding; Genentech: Research Funding. Jakubowiak: Gracell: Membership on an entity's Board of Directors or advisory committees; Amgen: Membership on an entity's Board of Directors or advisory committees; Abbvie: Membership on an entity's Board of Directors or advisory committees; BMS: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Karyopharm: Membership on an entity's Board of Directors or advisory committees; GSK: Membership on an entity's Board of Directors or advisory committees; Janssen: Membership on an entity's Board of Directors or advisory committees; Sanofi: Membership on an entity's Board of Directors or advisory committees. Chu: Celgene/BMS: Consultancy, Honoraria, Research Funding; Amgen: Consultancy, Honoraria; AstraZeneca: Consultancy, Honoraria; Gilead: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Teva: Consultancy, Honoraria. Gasparetto: Janssen: Consultancy; Sanofi: Consultancy, Honoraria, Speakers Bureau; Oncopeptide: Consultancy, Honoraria, Speakers Bureau; Karyopharm: Consultancy, Honoraria, Speakers Bureau; Gsk: Consultancy, Honoraria, Speakers Bureau. Lesokhin: pfizer: Consultancy, Research Funding; Behringer Ingelheim: Honoraria; Trillium Therapeutics: Consultancy; bristol myers squibb: Research Funding; Genetech: Research Funding; Iteos: Consultancy; Janssen: Honoraria, Research Funding; Serametrix, Inc: Patents & Royalties.

Most cancer patients succumb to disseminated disease because conventional systemic therapies lack spatiotemporal control of their toxic effects in vivo, particularly in a complicated milieu such as bone marrow where progenitor stem cells reside. Here, we demonstrate the treatment of disseminated cancer by photoactivatable drugs using radiopharmaceuticals. An orthogonal-targeting strategy and a contact-facilitated nanomicelle technology enabled highly selective delivery and co-localization of titanocene and radiolabelled fluorodeoxyglucose in disseminated multiple myeloma cells. Selective ablation of the cancer cells was achieved without significant off-target toxicity to the resident stem cells. Genomic, proteomic and multimodal imaging analyses revealed that the downregulation of CD49d, one of the dimeric protein targets of the nanomicelles, caused therapy resistance in small clusters of cancer cells. Similar treatment of a highly metastatic breast cancer model using human serum albumin-titanocene formulation significantly inhibited cancer growth. This strategy expands the use of phototherapy for treating previously inaccessible metastatic disease., Most of the systemic cancer therapies lack spatiotemporal control. Here, the authors show targeted activation of a light-sensitive drug by radiopharmaceuticals in disseminated cancer cells as potential in vivo treatment of metastatic diseases with reduced off-target toxicity.

Background Elranatamab (PF-06863135), a humanized bispecific molecule, targets both BCMA expressed in MM and CD3 on T cells. MagnetisMM-1 (ClinicalTrials.gov ID: NCT03269136) is a Phase 1 study of elranatamab with the aim of characterizing the efficacy, safety, pharmacokinetics, and pharmacodynamics of elranatamab as single agent and in combination with immunomodulatory agents for pts with relapsed or refractory MM. Methods Pts received single agent elranatamab 80, 130, 215, 360, 600, or 1000µg/kg/week subcutaneously. A modified toxicity probability interval method was used for escalation, with monitoring for dose-limiting toxicity (DLT) to the end of the first cycle. Treatment emergent adverse events (TEAEs) were graded by Common Terminology Criteria for Adverse Events v4.03, and cytokine release syndrome (CRS) by American Society for Transplantation and Cellular Therapy criteria (Biol Blood Marrow Transplant. 2019;25:625). Responses and minimal residual disease (MRD) status (by next-generation sequencing at a sensitivity of 1 × 10-5) were assessed by International Myeloma Working Group criteria. Pharmacokinetics, cytokine profiling, and T cell immunophenotyping were performed. Results 30 pts had received elranatamab as of 4-Feb-2021 at 80 (n=6), 130 (n=4), 215 (n=4), 360 (n=4), 600 (n=6), or 1000 (n=6) µg/kg. Pts had a median of 8 prior treatments; 87% had triple refractory disease, 97% prior anti-CD38 therapy, and 23% prior BCMA-directed antibody drug conjugate or chimeric antigen receptor T cell therapy. Common all causality TEAEs included lymphopenia (n=25, 83%; 20% G3, 63% G4), CRS (n=22, 73%; none >G2), anemia (n=18, 60%; 50% G3, 0% G4), neutropenia (n=16, 53%; 23% G3, 30% G4), thrombocytopenia (n=16, 53%; 17% G3, 20% G4), and injection site reaction (n=15, 50%; none >G2). Both CRS and immune effector cell-associated neurotoxicity syndrome (n=6, 20%) were limited to ≤G2; median durations were 3 and 2.5 days, respectively. No DLT was observed. Exposure increased with dose, and Tmax ranged from 3–7 days. Cytokine increases occurred with the first dose, and increased T cell proliferation was observed in peripheral blood. For doses ≥215µg/kg, confirmed overall response rate (ORR) was 70% (n=14/20) including partial response (PR; n=1), very good PR (VGPR; n=7), complete response (CR; n=1), and stringent CR (sCR; n=5). The majority of patients with sCR achieved MRD negativity. Median time to response was 22 days. In this dosing group, 3 of 4 pts (75%) with prior BCMA-directed therapy achieved response. Confirmed ORR at the recommended phase 2 dose (RP2D) of 1000µg/kg was 83% (n=5/6). Conclusions Elranatamab achieved confirmed ORR of 83% at RP2D with a manageable safety profile for pts with relapsed or refractory MM. These results confirm the feasibility and potential of BCMA-directed immunotherapy for malignant plasma cell disorders, and support further development of elranatamab for pts with MM. This study was sponsored by Pfizer.

Context Elranatamab (PF-06863135), a humanized bispecific monoclonal antibody (IgG2a), targets BCMA expressed in MM and CD3 on T-cells. Objective Characterize efficacy, safety, pharmacokinetics, and pharmacodynamics of elranatamab. Design Phase 1 study (MagnetismMM-1; NCT03269136). Data cut-off: 4 February 2021. Patients Relapsed or refractory MM. Intervention 80, 130, 215, 360, 600, or 1000 µg/kg/week subcutaneously. Main Outcome Measures 1) Treatment-emergent adverse events (TEAEs) graded by CTCAE v4.03 and cytokine release syndrome (CRS) by ASTCT criteria. 2) International Myeloma Working Group criteria-assessed response. 3) Pharmacokinetics, cytokine profiling, and T-cell immunophenotyping. Results Thirty patients received elranatamab at 80 (n=6), 130 (n=4), 215 (n=4), 360 (n=4), 600 (n=6), or 1000 (n=6) µg/kg. Patients had a median of 8 prior treatments; 87% had triple refractory disease, 97% prior anti-CD38 therapy, and 23% prior BCMA-directed antibody drug conjugate or chimeric antigen receptor T-cell therapy. Common all causality TEAEs included lymphopenia (n=25, 83%; 20% G3, 63% G4), CRS (n=22, 73%; none >G2), anemia (n=18, 60%; 50% G3, 0% G4), neutropenia (n=16, 53%; 23% G3, 30% G4), thrombocytopenia (n=16, 53%; 17% G3, 20% G4), and injection site reaction (n=15, 50%; none >G2). CRS and immune effector cell-associated neurotoxicity syndrome (n=6, 20%) were limited to ≤G2; median durations were 3 and 2.5 days, respectively. No dose-limiting toxicity was observed. Exposure increased with dose and Tmax ranged from 3–7 days. Cytokine increases occurred with the first dose, and increased T-cell proliferation was observed in peripheral blood. For doses ≥215 µg/kg, the confirmed overall response rate (ORR) was 70% (n=14/20); partial response (PR; n=1), very good PR (VGPR; n=7), complete response (CR; n=1), and stringent CR (n=5). Median time to response was 22 days. In this dosing group, 3 of 4 pts (75%) with prior BCMA-directed therapy achieved response. Confirmed ORR at the recommended phase 2 dose (RP2D) of 1000 µg/kg was 83% (n=5/6). Conclusions Elranatamab achieved confirmed ORR of 83% at RP2D with a manageable safety profile for patients with relapsed or refractory MM. These results support further development of elranatamab for patients with MM. This study was sponsored by Pfizer.

Obesity is the only known modifiable risk factor for multiple myeloma (MM), an incurable cancer of bone marrow plasma cells. The mechanism linking the two is unknown. Obesity is associated with an increased risk of sleep apnea, which results in chronic intermittent hypoxia (CIH), and drives solid tumor aggressiveness. Given the link between CIH and solid tumor progression, we tested the hypothesis that CIH drives the proliferation of MM cells in culture and their engraftment and progression in vivo. Malignant mouse 5TGM1 cells were cultured in CIH, static hypoxia, or normoxia as a control in custom, gas-permeable plates. Typically MM-resistant C57BL/6J mice were exposed to 10 h/day CIH (AHI = 12/h), static hypoxia, or normoxia for 7 days, followed by injection with 5TGM1 cells and an additional 28 days of exposure. CIH and static hypoxia slowed the growth of 5TGM1 cells in culture. CIH-exposed mice developed significantly more MM than controls (67 vs. 12%, P = 0.005), evidenced by hindlimb paralysis, gammopathy, bone lesions, and bone tumor formation. Static hypoxia was not a significant driver of MM progression and did not reduce survival ( P = 0.117). Interestingly, 5TGM1 cells preferentially engrafted in the bone marrow and promoted terminal disease in CIH mice, despite a lower tumor burden, compared with the positive controls. These first experiments in the context of hematological cancer demonstrate that CIH promotes MM through mechanisms distinct from solid tumors and that sleep apnea may be a targetable risk factor in patients with or at risk for blood cancer.

8006 Background: Elranatamab (PF-06863135) is a humanized bispecific monoclonal antibody (IgG2a) that targets BCMA, a member of the tumor necrosis factor receptor superfamily expressed in MM, and CD3 on T cells. We reported results for intravenous (IV) dosing (Raje et al. Blood. 2019;134(S1):1869) and now update for subcutaneous (SC) dosing from the ongoing Phase 1 study (MagnetisMM-1). Methods: Patients (pts) received elranatamab at 80, 130, 215, 360, 600, and 1000μg/kg SC weekly. A modified toxicity probability interval method was used for escalation, with monitoring for dose-limiting toxicity (DLT) to end of the first cycle. Treatment-emergent adverse events (TEAEs) were graded by Common Terminology Criteria for Adverse Events (v4.03), and cytokine release syndrome (CRS) by American Society for Transplantation and Cellular Therapy criteria (Lee et al. Biol Blood Marrow Transplant. 2019;25:625). Response was assessed by International Myeloma Working Group criteria. Pharmacokinetics, cytokine profiling, and T cell immunophenotyping were performed. Results: 30 pts had received elranatamab as of 4-Aug-2020 at 80 (n = 6), 130 (n = 4), 215 (n = 4), 360 (n = 4), 600 (n = 6), or 1000 (n = 6) μg/kg SC weekly. Pts had a median of 8 prior treatments; 87% had triple refractory disease, 97% had prior anti-CD38 therapy, and 23% had prior BCMA-directed antibody drug conjugate or chimeric antigen receptor T cell therapy. The most common all causality TEAEs included lymphopenia (n = 24, 80%; 20% G3, 60% G4), CRS (n = 22, 73%; none > G2), anemia (n = 17, 57%; 43% G3, 3% G4), injection site reaction (n = 16, 53%; none > G2), thrombocytopenia (n = 16, 53%; 23% G3, 17% G4), and neutropenia (n = 12, 40%; 17% G3, 17% G4). Both CRS and immune effector cell-associated neurotoxicity syndrome (n = 6, 20%) were limited to ≤G2 with median durations of 2 and 1.5 days, respectively. No DLT was observed. Exposure increased with dose, and Tmax ranged from 3–7 days. Cytokine increases occurred with the first dose, and increased T-cell proliferation was observed in peripheral blood. The overall response rate (ORR) for doses ≥215μg/kg was 75% (n = 15/20) including partial response (PR; n = 6), very good PR (VGPR; n = 3), complete response (CR; n = 1), and stringent CR (sCR; n = 5). Median time to response was 22 days, and 3 of 4 pts (75%) with prior BCMA-directed therapy achieved response (VGPR, n = 2 and sCR, n = 1). Updated data, including duration of response, will be presented. Conclusions: Elranatamab demonstrated a manageable safety profile, and SC doses ≥215μg/kg achieved ORR of 75% with CR/sCR rate of 30%. These results demonstrate the safety and efficacy of SC elranatamab in this relapsed/refractory population and support ongoing development of elranatamab for pts with MM, both as monotherapy and in combination with standard or novel therapies. Clinical trial information: NCT03269136.

BackgroundThe molecular determinants of clinical responses to decitabine therapy in patients with acute myeloid leukemia (AML) or myelodysplastic syndromes (MDS) are unclear. MethodsWe enrolled 84 adult patients with AML or MDS in a single-institution trial of decitabine to identify somatic mutations and their relationships to clinical responses. Decitabine was administered at a dose of 20 mg per square meter of body-surface area per day for 10 consecutive days in monthly cycles. We performed enhanced exome or gene-panel sequencing in 67 of these patients and serial sequencing at multiple time points to evaluate patterns of mutation clearance in 54 patients. An extension cohort included 32 additional patients who received decitabine in different protocols. ResultsOf the 116 patients, 53 (46%) had bone marrow blast clearance (

Overexpression of the multiple myeloma set domain (MMSET) Wolf-Hirschhorn syndrome candidate 1 gene, which contains an orphan box H/ACA class small nucleolar RNA, ACA11, in an intron, is associated with several cancer types, including multiple myeloma (MM). ACA11 and MMSET are overexpressed cotranscriptionally as a result of the t(4;14) chromosomal translocation in a subset of patients with MM. RNA sequencing of CD138+ tumor cells from t(4;14)-positive and -negative MM patient bone marrow samples revealed an enhanced oxidative phosphorylation mRNA signature. Supporting these data, ACA11 overexpression in a t(4;14)-negative MM cell line, MM1.S, demonstrated enhanced reactive oxygen species (ROS) levels. In addition, an enhancement of cell proliferation, increased soft agar colony size, and elevated ERK1/2 phosphorylation were observed. This ACA11-driven hyperproliferative phenotype depended on increased ROS levels as exogenously added antioxidants attenuate the increased proliferation. A major transcriptional regulator of the cellular antioxidant response, nuclear factor (erythroid-derived 2)-like 2 (NRF2), shuttled to the nucleus, as expected, in response to ACA11-driven increases in ROS; however, transcriptional up-regulation of some of NRF2’s antioxidant target genes was abrogated in the presence of ACA11 overexpression. These data show for the first time that ACA11 promotes proliferation through inhibition of NRF2 function resulting in sustained ROS levels driving cancer cell proliferation.—Mahajan, N., Wu, H.-J., Bennett, R. L., Troche, C., Licht, J. D., Weber, J. D., Maggi, L. B., Jr., Tomasson, M. H. Sabotaging of the oxidative stress response by an oncogenic noncoding RNA.

Dis3 encodes a conserved RNase that degrades or processes all RNA species via an N-terminal PilT N terminus (PIN) domain and C-terminal RNB domain that harbor, respectively, endonuclease activity and 3′–5′ exonuclease activity. In Schizosaccharomyces pombe, dis3 mutations cause chromosome missegregation and failure in mitosis, suggesting dis3 promotes cell division. In humans, apparently hypomorphic dis3 mutations are found recurrently in multiple myeloma, suggesting dis3 opposes cell division. Except for the observation that RNAi-mediated depletion of dis3 function drives larval arrest and reduces tissue growth in Drosophila, the role of dis3 has not been rigorously explored in higher eukaryotic systems. Using the Drosophila system and newly generated dis3 null alleles, we find that absence of dis3 activity inhibits cell division. We uncover a conserved CDK1 phosphorylation site that when phosphorylated inhibits Dis3’s exonuclease, but not endonuclease, activity. Leveraging this information, we show that Dis3’s exonuclease function is required for mitotic cell division: in its absence, cells are delayed in mitosis and exhibit aneuploidy and overcondensed chromosomes. In contrast, we find that modest reduction of dis3 function enhances cell proliferation in the presence of elevated Ras activity, apparently by accelerating cells through G2/M even though each insult by itself delays G2/M. Additionally, we find that dis3 and ras genetically interact in worms and that dis3 can enhance cell proliferation under growth stimulatory conditions in murine B cells. Thus, reduction, but not absence, of dis3 activity can enhance cell proliferation in higher organisms.

Background: Persons of African ancestry (AA) experience a 1.5-2-fold risk of multiple myeloma (MM) compared to persons of European ancestry (EA). We assembled a set of MM patients with self-reported AA in order to evaluate the contribution of genetics to etiology in this high-risk group. Methods: Here we present the results of a meta-analysis of two GWAS in 1,813 cases and 8,871 controls of AA. We also conducted an admixture mapping scan to identify risk alleles associated with local ancestry, fine-mapped the 23 known susceptibility loci to find markers that could better capture MM risk in individuals of AA, and constructed a polygenic risk score (PRS) to assess the aggregated effect of known MM risk alleles. Finally, we conducted an eQTL analysis measuring gene expression in those genes harboring a risk variant in malignant plasma cells from 292 of the patients from a single site. Results: In GWAS analysis, we identified two suggestive novel loci located at 9p24.3 and 9p13.1 at P Conclusion: Our study shows that common genetic variation contributes to MM risk individuals of AA. This abstract is also being presented as Poster C040. Citation Format: Zhaohui Du, Niels Weinhold, Gregory Chi Song, Kristen A. Rand, David J. Van Den Berg, Amie E. Hwang, Xin Sheng, Victor Hom, Sikander Ailawadhi, Ajay K. Nooka, Seema Singhal, Karen Pawlish, Edward Peters, Cathryn Bock, Ann Mohrbacher, Alexander Stram, Sonja I. Berndt, William J. Blot, Graham Casey, Victoria L. Stevens, Rick Kittles, Phyllis J. Goodman, W. Ryan Diver, Anselm Hennis, Barbara Nemesure, Eric A. Klein, Benjamin A. Rybicki, Janet L. Stanford, John S. Witte, Lisa Signorello, Esther M. John, Leslie Bernstein, Antoinette Stroup, Owen W. Stephens, Maurizio Zangari, Frits Van Rhee, Andrew Olshan, Wei Zheng, Jennifer J. Hu, Regina Ziegler, Sarah J. Nyante, Sue Ann Ingles, Michael Press, John David Carpten, Stephen Chanock, Jayesh Mehta, Graham A Colditz, Jeffrey Wolf, Thomas G. Martin, Michael Tomasson, Mark A. Fiala, Howard Terebelo, Nalini Janakiraman, Laurence Kolonel, Kenneth C. Anderson, Loic Le Marchand, Daniel Auclair, Brian C.-H. Chiu, Elad Ziv, Daniel Stram, Ravi Vij, Leon Bernal-Mizrachi, Gareth J. Morgan, Jeffrey A. Zonder, Carol Ann Huff, Sagar Lonial, Robert Z. Orlowski, David V. Conti, Christopher A. Haiman, Wendy Cozen. A meta-analysis of genome-wide association study and eQTL analysis of multiple myeloma among African Americans [abstract]. In: Proceedings of the Twelfth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2019 Sep 20-23; San Francisco, CA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2020;29(6 Suppl_2):Abstract nr PR05.

Background Treatment failures in cancers, including multiple myeloma (MM), are most likely due to the persistence of a minor population of tumor-initiating cells (TICs), which are noncycling or slowly cycling and very drug resistant. Methods Gene expression profiling and real-time quantitative reverse transcription polymerase chain reaction were employed to define genes differentially expressed between the side-population cells, which contain the TICs, and the main population of MM cells derived from 11 MM patient samples. Self-renewal potential was analyzed by clonogenicity and drug resistance of CD24+ MM cells. Flow cytometry (n = 60) and immunofluorescence (n = 66) were applied on MM patient samples to determine CD24 expression. Therapeutic effects of CD24 antibodies were tested in xenograft MM mouse models containing three to six mice per group. Results CD24 was highly expressed in the side-population cells, and CD24+ MM cells exhibited high expression of induced pluripotent or embryonic stem cell genes. CD24+ MM cells showed increased clonogenicity, drug resistance, and tumorigenicity. Only 10 CD24+ MM cells were required to develop plasmacytomas in mice (n = three of five mice after 27 days). The frequency of CD24+ MM cells was highly variable in primary MM samples, but the average of CD24+ MM cells was 8.3% after chemotherapy and in complete-remission MM samples with persistent minimal residual disease compared with 1.0% CD24+ MM cells in newly diagnosed MM samples (n = 26). MM patients with a high initial percentage of CD24+ MM cells had inferior progression-free survival (hazard ratio [HR] = 3.81, 95% confidence interval [CI] = 5.66 to 18.34, P < .001) and overall survival (HR = 3.87, 95% CI = 16.61 to 34.39, P = .002). A CD24 antibody inhibited MM cell growth and prevented tumor progression in vivo. Conclusion Our studies demonstrate that CD24+ MM cells maintain the TIC features of self-renewal and drug resistance and provide a target for myeloma therapy.

Purpose Recent advances have uncovered therapeutic interventions that might reduce the risk of progression of premalignant diagnoses, such as monoclonal gammopathy of undetermined significance (MGUS) to multiple myeloma (MM). It remains unclear how to best screen populations at risk and how to evaluate the ability of these interventions to reduce disease prevalence and mortality at the population level. To address these questions, we developed a computational modeling framework. Materials and Methods We used individual-based computational modeling of MGUS incidence and progression across a population of diverse individuals to determine best screening strategies in terms of screening start, intervals, and risk-group specificity. Inputs were life tables, MGUS incidence, and baseline MM survival. We measured MM-specific mortality and MM prevalence after MGUS detection from simulations and mathematic modeling predictions. Results Our framework is applicable to a wide spectrum of screening and intervention scenarios, including variation of the baseline MGUS to MM progression rate and evolving MGUS, in which progression increases over time. Given the currently available point estimate of progression risk reduction to 61% risk, starting screening at age 55 years and performing follow-up screening every 6 years reduced total MM prevalence by 19%. The same reduction could be achieved with starting screening at age 65 years and performing follow-up screening every 2 years. A 40% progression risk reduction per patient with MGUS per year would reduce MM-specific mortality by 40%. Specifically, screening onset age and screening frequency can change disease prevalence, and progression risk reduction changes both prevalence and disease-specific mortality. Screening would generally be favorable in high-risk individuals. Conclusion Screening efforts should focus on specifically identified groups with high lifetime risk of MGUS, for which screening benefits can be significant. Screening low-risk individuals with MGUS would require improved preventions.