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Supplementary Data from 3-Phosphoinositide–Dependent Protein Kinase-1 Regulates Proliferation and Survival of Cancer Cells with an Activated Mitogen-Activated Protein Kinase Pathway

Sarilumab is a human monoclonal antibody against interleukin (IL)-6Rα that has been approved for the treatment of adult patients with moderately to severely active rheumatoid arthritis (RA) and an inadequate response or intolerance to one or more disease-modifying antirheumatic drugs (DMARDs). Mild liver function test abnormalities have been observed in patients treated with sarilumab. We describe a genome-wide association study of bilirubin elevations in RA patients treated with sarilumab. Array genotyping and exome sequencing were performed on DNA samples from 1075 patients. Variants in the UGT1A1 gene were strongly associated with maximum bilirubin elevations in sarilumab-treated patients (rs4148325; p = 2.88 × 10−41) but were not associated with aminotransferase elevations. No other independent loci showed evidence of association with bilirubin elevations after sarilumab treatment. These findings suggest that most bilirubin increases during sarilumab treatment are related to genetic variation in UGT1A1 rather than underlying liver injury.

BackgroundFibrodysplasia ossificans progressiva (FOP), an ultra-rare disorder caused by mutations in the gene encoding activin A receptor type 1 (ACVR1), is characterized by painful flare-ups and cumulative heterotopic ossification (HO). Garetosmab, a fully-human monoclonal antibody blocking activin A, prevents HO in FOP mice.MethodsLUMINA-1 (NCT03188666) was a phase 2, multi-center, randomized, double-blind, placebo-controlled study evaluating the safety, tolerability, and effects on HO of intravenous (IV) garetosmab 10 mg/kg every 4 weeks (Q4W). Adult patients with FOP were randomized to garetosmab or placebo for 28 weeks (Period_1), followed by an open-label period (Period_2). After Period_2, patients were allowed to stay on garetosmab in an open-label extension. For Period_1, primary endpoints were HO total lesion activity (HO-TLA) by18F-sodium fluoride positron emission tomography (18F-NaF PET) and HO total lesion volume by computed tomography (CT). The Period_2 primary endpoint compared the number of new lesions in Period_2 versus Period_1. The safety primary endpoint was incidence and severity of TEAEs through the end of the Period 1 at week 28.FindingsPatients (n=44) were randomized to garetosmab (n=20) or placebo (n=24). In Period_1, there was a trend for garetosmab to decrease HO-TLA versus placebo (24.6%;P=0.07), primarily driven by near complete prevention of new lesions (97% decrease by18F-NaF PET, post-hocP=0.009; 90% relative reduction by CT, post-hocP=0.017); flare-ups were significantly reduced (P=0.0005). For placebo patients transitioning to garetosmab in Period_2, no patients developed new HO lesions (0% in Period_2 versus 40.9% in Period_1;P=0.0027) by CT. All 44 patients met primary safety endpoint of at least one TEAE during Period 1. Garetosmab was associated with more adverse events than placebo: mild recurrent epistaxis, madarosis, and skin/soft tissue infections. Overall, the AEs were predominantly mild in severity, with no effect on patients’ ability to receive garetosmab. Five deaths (5/44; 11.4%) occurred either in Period_2 or the open-label extension. The deaths were associated with baseline disease severity in some, preexisting comorbidities in others and occurred following 8-16 doses (median: 15) of garetosmab in the open label/follow-up periods.InterpretationGaretosmab reduced flare-ups and prevented new HO lesions in FOP patients. Although side effects were mild to moderate, there were a relatively high number of deaths for a small study; the deaths were not related to epistaxis and considered unlikely to be related to garetosmab.FundingRegeneron Pharmaceuticals, Inc.

Background Elucidating the relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load and clinical outcomes is critical for understanding coronavirus disease 2019 (COVID-19). Methods The SARS-CoV-2 levels were analyzed by quantitative real-time polymerase chain reaction (RT-qPCR) of nasopharyngeal or oropharyngeal swab specimens collected at baseline, and clinical outcomes were recorded over 60 days from 1362 COVID-19 hospitalized patients enrolled in a multicenter, randomized, placebo-controlled phase 2/3 trial of sarilumab for COVID-19 (ClinicalTrials.gov NCT04315298). Results In post hoc analyses, higher baseline viral load, measured by both RT-qPCR cycle threshold and log10 copies/mL, was associated with greater supplemental oxygenation requirements and disease severity at study entry. Higher baseline viral load was associated with higher mortality, lower likelihood of improvement in clinical status and supplemental oxygenation requirements, and lower rates of hospital discharge. Viral load was not impacted by sarilumab treatment over time versus placebo. Conclusions These data support viral load as an important determinant of clinical outcomes in hospitalized patients with COVID-19 requiring supplemental oxygen or assisted ventilation.

We assessed pharmacokinetics (PK), pharmacodynamics (PD), and PK/PD relationships of interleukin‐6 (IL‐6), soluble IL‐6 receptor, and C‐reactive protein (CRP) in serum, and absolute neutrophil count (ANC) in blood following single doses of subcutaneous sarilumab versus intravenous tocilizumab (NCT02097524) from patients with rheumatoid arthritis (RA) who are inadequate responders to methotrexate (MTX) and on a stable dose of MTX. Patients with RA randomized (1:1:1:1) to single‐dose sarilumab (150 or 200 mg subcutaneously) or tocilizumab (4 or 8 mg/kg intravenously) were included (n = 101), and PK, PD, and PK/PD relationships and safety were assessed over 6 weeks postdose. PK profiles for both drugs are described by parallel linear and nonlinear target‐mediated clearance pathways. PD markers showed similar onset of effect during the first week postdose, regardless of dose or route of administration. CRP and ANC decreased, with median postdose nadirs at 7‐15 days for CRP and 3‐5 days for ANC. Both drugs at low and high doses achieved the same nadir for ANC and a similar return toward baseline within 2 weeks postdose, suggesting a saturation of effect. Safety profiles of sarilumab and tocilizumab were generally similar. In conclusion, despite differences in PK, the onset of the decrease in CRP (efficacy) and ANC (safety) after a single dose were similar for subcutaneous sarilumab and intravenous tocilizumab. PD effects and safety were consistent with previous studies.

Evidence suggests that effects of interleukin-6 pathway inhibitors sarilumab, tocilizumab, and sirukumab on absolute neutrophil count (ANC) are due to margination of circulating neutrophils into rapidly mobilizable noncirculating pools. We developed a population pharmacodynamic model using compartments for neutrophil margination and ANC-specific tolerance to describe rapid, transient ANC changes in blood following administration of subcutaneous sarilumab and intravenous/subcutaneous tocilizumab based on data from 322 patients with rheumatoid arthritis in two single-dose (NCT02097524 and NCT02404558) and one multiple-dose (NCT01768572) trials. The model incorporated a tolerance compartment to account for ANC nadir and beginning of recovery before maximal drug concentration after subcutaneous dosing, and absence of a nadir plateau when the ANC response is saturated after subcutaneous or intravenous dosing. The model effectively describes the ANC changes and supports neutrophil margination and tolerance as an explanation for the absence of increased infection risk associated with low ANC due to interleukin-6 pathway inhibitor treatment.

Background Interleukin-6 (IL-6) is a pleiotropic cytokine that plays a key role in the pathogenesis of rheumatoid arthritis. Sarilumab is a human monoclonal antibody that binds membrane-bound and soluble IL-6 receptor-α to inhibit IL-6 signalling. The aim of this study was to compare the effects of sarilumab and adalimumab (a tumour necrosis factor alpha inhibitor) monotherapy on levels of circulating biomarkers associated with the acute-phase response, bone remodelling, atherothrombosis, anaemia of chronic disease and markers purported to reflect synovial lymphoid and myeloid cell infiltrates, as well as the potential of these biomarkers to differentially predict clinical and patient-reported outcomes with sarilumab vs. adalimumab. Methods In this post hoc analysis, serum samples were analysed at baseline and prespecified post-treatment timepoints up to week 24 in adults with moderate-to-severe active rheumatoid arthritis intolerant of or inadequate responders to methotrexate from the MONARCH trial (NCT02332590). Results Greater reductions in C-reactive protein (CRP; − 94.0% vs. –24.0%), serum amyloid A (SAA; − 83.2% vs. –17.4%), total receptor activator of nuclear factor-κB ligand (RANKL; − 18.3% vs. 10.5%) and lipoprotein (a) (− 41.0% vs. –2.8%) were observed at week 24 with sarilumab vs. adalimumab, respectively (adjusted p N-terminal propeptide (P1NP) were observed with sarilumab vs. adalimumab at week 24 (22.8% vs. 6.2%, p = 0.027). Patients with high baseline SAA, CRP and matrix metalloproteinase-3 (MMP-3) were more likely to achieve clinical efficacy, including American College of Rheumatology 20% improvement criteria and Disease Activity Score (28 joints)-CRP Conclusion Sarilumab was associated with greater positive effects on bone remodelling and decreases in biomarkers of the acute-phase response, synovial inflammation and cardiovascular risk vs. adalimumab. High baseline concentrations of SAA, CRP and MMP-3 are predictive of clinical and patient-reported outcome responses to sarilumab treatment and prospective validation is warranted to confirm these results. Trial registration ClinicalTrials.gov, NCT02332590. Registered on 5 January 2015

A subset of hospitalized COVID-19 patients, particularly the aged and those with comorbidities, develop the most severe form of the disease, characterized by acute respiratory disease syndrome (ARDS), coincident with experiencing a “cytokine storm.” Here, we demonstrate that cytokines which activate the NF-κB pathway can induce activin A. Patients with elevated activin A, activin B, and FLRG at hospital admission were associated with the most severe outcomes of COVID-19, including the requirement for mechanical ventilation, and all-cause mortality. A prior study showed that activin A could decrease viral load, which indicated there might be a risk to giving COVID-19 patients an inhibitor of activin. To evaluate this, the role for activin A was examined in a hamster model of SARS-CoV-2 infection, via blockade of activin A signaling. The hamster model demonstrated that use of an anti-activin A antibody did not worsen the disease and there was no evidence for increase in lung viral load and pathology. The study indicates blockade of activin signaling may be beneficial in treating COVID-19 patients experiencing ARDS.

BACKGROUNDSarilumab (anti-interleukin-6 receptor-α monoclonal antibody) may attenuate the inflammatory response in Covid-19.METHODSWe performed an adaptive, phase 2/3, randomized, double-blind, placebo-controlled trial of intravenous sarilumab 200 mg or 400 mg in adults hospitalized with Covid-19. The phase 3 primary analysis population (cohort 1) was patients with critical Covid-19 receiving mechanical ventilation (MV) randomized to sarilumab 400 mg or placebo. The primary end point for phase 3 was the proportion of patients with ≥1-point improvement in clinical status from baseline to day 22.RESULTSFour-hundred fifty-seven (457) and 1365 patients were randomized and treated in phases 2 and 3, respectively. Among phase 3 critical patients receiving MV (n=289; 34.3% on corticosteroids), the proportion with ≥1-point improvement in clinical status (alive not receiving MV) at day 22 was 43.2% in sarilumab 400 mg and 35.5% in placebo (risk difference [RD] +7.5%; 95% confidence interval [CI], –7.4 to 21.3; P=0.3261), representing a relative risk improvement of 21.7%. Day 29 all-cause mortality was 36.4% in sarilumab 400 mg versus 41.9% in placebo (RD –5.5%; 95% CI, –20.2 to 8.7; relative risk reduction 13.3%). In post hoc analyses pooling phase 2 and 3 critical patients receiving MV, the hazard ratio (HR) for death in sarilumab 400 mg compared with placebo was 0.76 (95% CI, 0.51 to 1.13) overall, improving to 0.49 (95% CI, 0.25 to 0.94) in patients receiving corticosteroids at baseline.CONCLUSIONIn hospitalized patients with Covid-19 receiving MV, numerical benefits with sarilumab did not achieve statistical significance, but benefit may be greater in patients receiving corticosteroids. A larger study is required to confirm this observed numerical benefit.(ClinicalTrials.gov number, NCT04315298)

SummaryA fraction of COVID-19 patients develop the most severe form, characterized by Acute Respiratory Disease Syndrome (ARDS). The molecular mechanisms causing COVID-19-induced ARDS have yet to be defined, though many studies have documented an increase in cytokines known as a “cytokine storm.” Here, we demonstrate that cytokines that activate the NF-kappaB pathway can induce Activin A and its downstream marker, FLRG. In hospitalized COVID-19 patients elevated Activin A/FLRG at baseline were predictive of the most severe longitudinal outcomes of COVID-19, including the need for mechanical ventilation, lack of clinical improvement and all-cause mortality. Patients with Activin A/FLRG above the sample median were 2.6/2.9 times more likely to die, relative to patients with levels below the sample median, respectively. The study indicates high levels of Activin A and FLRG put patients at risk of ARDS, and blockade of Activin A may be beneficial in treating COVID-19 patients experiencing ARDS.

Background Despite new regimens approved for RRMM, patients still relapse, and new therapies are needed. T-cell directed therapies that target bone marrow plasma cells (BMPCs), including CD3 bispecific antibodies, have shown promise for the treatment of RRMM. REGN5458, a B-cell maturation antigen (BCMA) xCD3 bispecific antibody, demonstrated an acceptable safety and tolerability profile with early, deep, and durable efficacy in heavily pretreated and triple refractory patients with RRMM [1]. Aim To elucidate disease aspects amenable to T-cell-directed therapies targeting plasma cells, such as REGN5458, we characterized the plasma and immune composition of baseline BMA and core biopsies from patients with RRMM, and evaluated relationships between bone marrow profile, secretory measures of disease, and response. Methods Patients with progressive RRMM (triple refractory or intolerant to prior lines of systemic therapy, including a proteasome inhibitor, immunomodulatory agent, and anti-CD38 antibody), were treated with REGN5458 (NCT03761108). Matched BMA and biopsy samples obtained at screening were analyzed by multiplex immunohistochemistry (IHC, N=48) and multiparameter flow cytometry (N=81). Cell numbers and phenotypes were correlated to secretory measures of disease, including serum M-protein, immunoglobulin-free light chain (FLC) assays and R-ISS staging. Results Biopsy analysis revealed a variable BMPC burden in RRMM patients. Median percentage of BMPCs by CD138 IHC was 22.5% (range 1–95%). There was no correlation between BMPC burden and serum M-protein levels, but a modest correlation between BMPC burden and serum FLC (rho=0.66; p=0.01). The majority of CD138 biopsy BMPCs in RRMM patients expressed BCMA by IHC; levels varied between patients (median BCMA+ H scores: 45 and 200 for membrane and cytoplasmic staining). BCMA IHC expression was not associated with IMWG response to REGN5458,1 and did not correlate with soluble BCMA levels at study initiation. BMA analysis by flow cytometry revealed variable levels of abnormal BMPCs in patients with RRMM (median: 2.2% [range 0–68.7%]). BCMA expression was variable in all BMPCs; 53.1% of patients had higher BCMA staining intensity relative to CD38: ratios ranged from 1.2–6.6. Frequency of CD3+ T-cells in CD45+ BMA from RRMM patients ranged from 1.0–63.5%. Preliminary analysis suggests a higher frequency of T cells in R-ISS stage I compared to stage II. T-cell subset distribution in BMA from patients with RRMM reflected low CD8 TCM (5.0%) and predominantly TEM (37.0%) and TEMRA (41.0%). Conclusions Analyses of matched BMA and biopsy samples from heavily pretreated RRMM patients, reveal that most BMPC express BCMA, though soluble vs membrane-bound BCMA levels are heterogenous. Diversity in immune and plasma cell markers and subsets is also observed. Ongoing analyses include correlations of plasma and immune cell profile with response to T-cell-targeting therapies such as REGN5458.

Background: Elucidating the relationship between severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) viral load and clinical outcomes is critical for understanding COVID-19. Methods: SARS-CoV-2 levels were analysed by quantitative real-time polymerase chain reaction (RT-qPCR) of naso- or oro-pharyngeal swab specimens collected at baseline and clinical outcomes were recorded over 60 days from 1362 COVID-19 hospitalised patients enrolled in a multi-center, randomized, placebo-controlled phase II/III trial of sarilumab for COVID-19 (NCT04315298). Findings: In post-hoc analyses, higher baseline viral load, measured by both RT-qPCR cycle threshold (Ct) and log10 copies/mL, was associated with greater supplemental oxygenation requirements and disease severity at study entry. Higher baseline viral load was associated with higher mortality, lower likelihood of improvement in clinical status and supplemental oxygenation requirements, and lower rates of hospital discharge. Viral load was not impacted by sarilumab treatment over time compared with placebo. Interpretation: These data support viral load as an important determinant of clinical outcomes in hospitalized patients with COVID-19 requiring supplemental oxygen or assisted ventilation. Trial Registration: NCT04315298 Funding Statement: Supported by Regeneron Pharmaceuticals, Inc. and Sanofi. Certain aspects of this project have been funded in whole or in part with federal funds from the Department of Health and Human Services, Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority, under OT number: HHSO100201700020C. Declaration of Interests: All authors are employees or employees and shareholders of Regeneron Pharmaceuticals, Inc. Ethics Approval Statement: The local institutional review board or ethics committee at each centre oversaw trial conduct and documentation. All patients provided written informed consent before participation. Ethics approval was obtained from the following ethics review boards: WCG IRB, Puyallup, WA (IRB00000533); Oregon Health & Science University, Portland, OR (MOD00027616); Institutional Review Board University of Florida, Gainesville, FL (IRB202000779); Columbia University, Human Research Protection Office and IRBs, New York, NY (IRB-AAAS9615); Johns Hopkins Medicine, Office of Human Subjects Research, IRB, Baltimore, MD (IRB00246576/CIR00058074); NYU School Of Medicine, New York, NY (I20-00351_MOD03); Northwestern University IRB, Chicago, IL (STU00212239-MOD0012); Westchester Medical Center, NY Medical College, Office of Research Administration, Valhalla, NY (IRBReg#00000428); Portland Health and Services IRB Providence – St. Johns, Portland, OR (MOD2020001024); Cornell Weill Medicine IRB, New York, NY (IRB00009419); Providence St. Joseph IRB, Renton, WA (MOD2020001029); Providence Health and Services IRB, Portland, OR (MOD2020000519); Ascension St. John Hospital, Tulsa, OK (IRB#00001980); Geisinger IRB, Danville, PA (IRB#0008345).

Background Multiple myeloma (MM) is an incurable plasma cell malignancy with significant heterogeneity in clinical presentation. Plasma cells are antibody-producing cells of lymphoid origin that are resident in secondary lymphoid organs and in the bone marrow (BM). The detection of circulating malignant plasma cells using flow cytometry has also been described in patients with MM. Enumerating and phenotyping malignant plasma cells in the BM and peripheral blood (PB) may be of value when evaluating the presence of MM antigens targeted by therapies before and during treatment and at relapse. To this end, a flow cytometric panel was developed to enumerate and characterize malignant plasma cells and additional immune subsets. Methods PB and BM aspirates (BMA) were obtained from healthy donors and MM donors who consented to research testing. MM cell lines were also used to spike into donor samples to detect specific antigens (collected in Cyto-Chex® blood collection tubes). Samples were then transferred to TruCount tubes to enumerate immune populations. Fluorescently labeled antibodies directed against CD38, CD138, CD56, CD45, BCMA were evaluated to assess parameters such as time and temperature stability of the reportable immune populations by monitoring the frequencies of the populations. In addition, the limit of quantitation, intra- and inter-assay precision were determined. Results The MM Counting Panel was optimized to leverage antigen expression and fluorophore combinations. A gating strategy enabled enumeration of MM cells based on antigens that can be further subdivided based on BCMA expression. Further testing showed that the precision in frequencies and absolute counts of key reportable populations was deemed acceptable (%CV of Conclusions A flow cytometric assay to enumerate and identify normal and malignant plasma cells in MM patients was successfully developed. The approach used can be applied to develop assays for other indications in which patients are treated with therapies.

Background Increased levels of cytokines, including interleukin-6 (IL-6), reflect inflammation and have been shown to be predictive of therapeutic responses, fatigue, pain, and depression in patients with rheumatoid arthritis (RA), but limited data exist on associations between IL-6 levels and health-related quality of life (HRQoL). This post hoc analysis of MONARCH phase III randomized controlled trial data evaluated the potential of baseline IL-6 levels to differentially predict HRQoL improvements with sarilumab, a fully human monoclonal antibody directed against both soluble and membrane-bound IL-6 receptor α (anti-IL-6Rα) versus adalimumab, a tumor necrosis factor α inhibitor, both approved for treatment of active RA. Methods Baseline serum IL-6 levels in 300/369 randomized patients were categorized into low (1.6–7.1 pg/mL), medium (7.2–39.5 pg/mL), and high (39.6–692.3 pg/mL) tertiles. HRQoL was measured at baseline and week (W)24 and W52 by Short Form 36 (SF-36) physical/mental component summary (PCS/MCS) and domain scores, Functional Assessment of Chronic Illness Therapy -fatigue, and duration of morning stiffness visual analog scale (AM-stiffness VAS). Linear regression of changes from baseline in HRQoL (IL-6 tertile, treatment, region as a stratification factor, and IL-6 tertile-by-treatment interaction as fixed effects) assessed predictivity of baseline IL-6 levels, with low tertile as reference. Pairwise comparisons of improvements between treatment groups were performed by tertile; least squares mean differences and 95% CIs were calculated. Similar analyses evaluated W24 patient-level response on minimum clinically important differences (MCID). Results At baseline, patients with high versus medium or low IL-6 levels (n = 100, respectively) reported worse (nominal p p p Conclusions Patients with high baseline IL-6 levels reported better improvements in PCS, physical functioning domain, and AM-stiffness scores with sarilumab versus adalimumab and safety consistent with IL-6R blockade. Trial registration NCT02332590. Registered on 5 January 2015

Background IL-6, a key cytokine in rheumatoid arthritis (RA) pathogenesis, is elevated in patient serum and synovial fluid. However, the impact of baseline IL-6 levels on patient-reported RA symptoms and health-related quality of life (HRQoL) following IL-6 blockade has not been explored. Sarilumab targets IL-6 receptor alpha, and sarilumab+methotrexate (MTX) significantly improved clinical and patient-reported outcomes vs MTX alone among MTX inadequate responders (IR) in MOBILITY/NCT01061736. This post-hoc analysis evaluated whether baseline IL-6 levels predict greater improvements in symptoms and HRQoL with sarilumab+MTX vs MTX. Methods 1,193 patients with moderate-to-severely active RA received MTX or MTX plus subcutaneous sarilumab at 200 mg (recommended dose) or 150 mg (recommended for management of laboratory abnormalities) every 2 weeks (q2w) and were grouped into tertiles according to baseline IL-6 levels. Patient-reported RA symptoms and HRQoL were measured at baseline and post-treatment (Weeks [W] 24 and 52). Results Baseline IL-6 tertiles among 1193 patients were 1.6-9.6 (low), 9.8-30.7 (medium), and 31.2-648.7 pg/mL (high). At baseline, patients with high IL-6 had greater disease activity, more radiographic structural damage, elevated CRP levels, and worse HRQoL (pain visual analog scale [VAS], SF36-physical component scores [PCS], and sleep VAS) vs those with low IL-6 (nominal p < 0.05) and generally reported greater improvements in symptoms and HRQoL with sarilumab+MTX vs placebo+MTX. Significant differences (nominal p < 0.005) between high and low tertiles were evident in improvement of pain VAS (W52) and SF-36 PCS (W24/W52) with sarilumab 200 mg q2w vs placebo, SF-36 mental component scores (both doses; W52) and FACIT-fatigue scores (both doses; W24/W52) vs placebo. Treatment-emergent adverse events were similar across IL-6 tertiles. Conclusion Among MTX-IR RA patients, high baseline IL-6 may predict better improvements in symptoms and HRQoL with sarilumab vs placebo, which was consistent with previous analyses across clinical/radiographic endpoints in the same study population. Disclosures V. Strand: Consultancies; AbbVie, Amgen, AstraZeneca, Biogen, BMS, Celltrion, CORRONA, Crescendo, Genentech/Roche, GSK, Janssen, Eli Lilly, Novartis, Pfizer, Regeneron Pharmaceuticals, Inc., Sandoz, Sanofi and U. J. Msihid: Corporate appointments; Employee of Sanofi. Shareholder/stock ownership; Sanofi. T. Kimura: Corporate appointments; Employee of Regeneron Pharmacueticals Inc. Shareholder/stock ownership; Regeneron Pharmacueticals Inc. A. Boyapati: Corporate appointments; Employee of Regeneron Pharmacueticals Inc. Shareholder/stock ownership; Regeneron Pharmacueticals Inc. G. St John: Corporate appointments; Employee of Regeneron Pharmacueticals Inc. Shareholder/stock ownership; Regeneron Pharmacueticals Inc. W. Wei: Corporate appointments; Employee of Regeneron Pharmacueticals Inc. Shareholder/stock ownership; Regeneron Pharmacueticals Inc.

Background Despite recent advances in treatment options, multiple myeloma (MM) remains incurable. We previously presented preliminary data from an ongoing Phase 1/2 trial (NCT03761108) demonstrating that REGN5458 (a BCMAxCD3 bispecific antibody) monotherapy had an acceptable safety and tolerability profile with early, deep, and durable responses in heavily pretreated patients (pts), with at least triple-refractory RRMM, (Madduri, ASH 2020, O291). Here we describe updated safety, overall response, and response durability in pts treated in the Phase 1 portion of this study. Methods The primary objectives of the Phase 1 portion of the study are to assess the safety, tolerability, and occurrence of dose-limiting toxicities of REGN5458 and to determine a recommended Phase 2 dose regimen (RP2DR). Key secondary objectives include: assessment of objective response rate as determined by the investigator, duration of response (DOR), and minimal residual disease status; pharmacokinetic (PK) evaluation; and characterization of immunogenicity. Pts with progressive RRMM, who were triple-refractory, or intolerant to prior lines of systemic therapy including a proteasome inhibitor, immunomodulatory agent, and anti-CD38 antibody are treated with REGN5458 monotherapy following a modified 3+3 dose-escalation design (4+3). Treatment consists of 16 weekly infusions of REGN5458, followed by q2w dosing, until disease progression. Response assessments are measured using modified International Myeloma Working Group criteria. Results As of data cut-off (June 10, 2021), 68 pts were treated with REGN5458 in the dose escalation cohort with full doses ranging from 3-400 mg. The median age at enrollment was 64 years (range, 41‒81) and 20.6% pts were ≥75 years. As per Revised International Staging System, stage was 1, 2 or 3 in 14.7%, 60.3% and 23.5% of pts respectively. Pts had a median of 5 prior lines of systemic therapy (range, 2-17) with the majority of pts (51.5%) being penta-refractory (see Table). The median duration of follow-up was 2.4 months (range, 0.1-20.8). Treatment-emergent adverse events (TEAE) were reported in 66 pts (97.1%), and Grade (Gr) ≥3 TEAEs in 52 (76.5%) pts. The most frequent TEAEs were fatigue in 29 pts (42.6%), Gr 1/2 in 26 pts (38.2%), Gr 3 in 3 pts (4.4%); cytokine release syndrome (CRS) in 26 pts (38.2%), CRS was Gr 1 in 23 pts (33.8%) and Gr 2 in 3 pts (4.4%). No pt had Gr ≥3 CRS or discontinued treatment due to CRS. There were no Gr ≥3 neurotoxicity events. Nausea was reported in 22 pts (32.4%). The severity of nausea was Gr 1 in 23.5% of pts and Gr 2 in 8.8% of pts. Treatment-related adverse events (TRAE) were reported in 56 patients (82.4%). The most frequent hematologic TRAE was neutropenia in 11 pts (16.2%), with Gr ≥3 severity in 9 of these pts (13.2%). The most frequent non-hematologic TRAEs were CRS (38.2%) and fatigue (20.6%). The safety profile was consistent across all dose levels, and there was no correlation between CRS and the full dose of REGN5458. Responses were observed at all dose levels. Amongst pts treated at the 96 and 200 mg dose levels, the response rate was 73.3% (11/15). Across all dose levels, 92.6% (n=25) of all responders achieved at least a very good partial response and 48.1% (n=13) of responders had a complete response (CR) or stringent CR. Pts without extramedullary plasmacytomas (EMP) responded more frequently than those with EMP. The Kaplan-Meier estimated median DOR was not reached and the probability of DOR ≥8 months was 92.1% (95% confidence interval: 72.1, 98.0), with responses ongoing up to 19 months at the latest data cut-off. Disease response was not impacted by level of BCMA expression in the core biopsy, as assessed by immunohistochemistry. Additional PK and biomarker data will be available at the time of presentation. Updated safety and efficacy data will also be presented. Conclusions In this updated analysis of the first-in-human study, REGN5458 continues to show an acceptable safety and tolerability profile, with Gr 2 CRS in only 4.4% of patients, and no Gr ≥3 CRS or neurotoxicity events. No new safety signals were observed during the additional follow-up period. Early, deep, and durable responses were seen in triple- to penta-refractory patients with RRMM, with a 73.3.% response rate at the combined 96 and 200 mg dose levels. The Phase 2 portion of the study is currently recruiting. Figure 1 Figure 1. Disclosures Zonder: Takeda: Consultancy, Membership on an entity's Board of Directors or advisory committees; BMS: Consultancy, Research Funding; Alnylam: Consultancy; Janssen: Consultancy; Amgen: Consultancy; Caelum Biosciences: Consultancy; Intellia: Consultancy; Regeneron: Consultancy. Richter: BMS, Karyopharm, Antengene: Membership on an entity's Board of Directors or advisory committees; Adaptive biotechnologies: Speakers Bureau; Janssen, Celgene: Membership on an entity's Board of Directors or advisory committees, Speakers Bureau; Tisch Cancer Institute: Icahn School of Medicine at Mount Sinai: Current Employment. Bumma: Amgen, Sanofi: Speakers Bureau; Janssen, Oncopeptides, Sanofi: Consultancy. Hoffman: BMS, Celgene: Honoraria. Bensinger: BMS, Janssen, Poseida, Regeneron, Trillium: Research Funding; Amgen, BMS, Janssen, Sanofi: Speakers Bureau. Xu: Regeneron Pharmaceuticals, Inc: Current Employment; Regeneron Pharmaceuticals, Inc: Current holder of stock options in a privately-held company. Chokshi: Regeneron Pharmaceuticals, Inc: Current holder of stock options in a privately-held company; Regeneron Pharmaceuticals, Inc: Current Employment. Boyapati: Regeneron Pharmaceuticals, Inc: Current Employment; Regeneron Pharmaceuticals, Inc: Current holder of stock options in a privately-held company. Sharma: Regeneron Pharmaceuticals, Inc.: Patents & Royalties: US17/112,564: Methods of Treating Multiple Myeloma with Bispecific anti-BCMA X anti-CD3 Antibodies (Status: Pending). Rodriguez Lorenc: Regeneron Pharmaceuticals, Inc: Current Employment; Regeneron Pharmaceuticals, Inc, Novartis Pharmaceuticals: Current holder of stock options in a privately-held company. Kroog: Regeneron Pharmaceuticals, Inc: Current Employment; Regeneron Pharmaceuticals, Inc: Current holder of stock options in a privately-held company. Lentzsch: Magenta Therapeutics: Current equity holder in publicly-traded company; Ossium Health: Consultancy; Caelum Biosciences: Consultancy, Current holder of individual stocks in a privately-held company; Oncopeptides: Consultancy; Sanofi: Consultancy, Research Funding; Karyopharm: Consultancy, Research Funding; Takeda: Consultancy; GSK: Consultancy; AbbVie: Consultancy; Celularity: Consultancy; Janssen: Consultancy; Kadmon: Current equity holder in publicly-traded company. Jagannath: Janssen Pharmaceuticals: Consultancy; Takeda: Consultancy; Legend Biotech: Consultancy; Karyopharm Therapeutics: Consultancy; Bristol Myers Squibb: Consultancy; Sanofi: Consultancy. OffLabel Disclosure: The data described in the abstract will report on use of REGN5458 in a Phase 1 clinical trial of patients with relapsed/refractory multiple myeloma

Background Increased levels of cytokines, including interleukin-6 (IL-6), reflect inflammation and are predictive of therapeutic responses in patients with RA. IL-6 has been implicated in fatigue, pain and depression in RA but a formal association with PROs has not been performed. Sarilumab, a fully human monoclonal antibody directed against IL-6Ra, is approved for treatment of moderate-to-severely active RA. The phase 3 MONARCH randomized controlled trial (NCT01061736) compared the efficacy and safety of sarilumab monotherapy vs adalimumab in RA patients who should not continue methotrexate treatment due to intolerance or inadequate responses. Greater reductions in disease activity and improvements in the clinical signs of RA and physical function were demonstrated with sarilumab vs adalimumab. A better understanding of the association between IL-6 levels and PROs is warranted to evaluate as a biomarker for guiding RA clinical decision-making. Objectives To evaluate, by post-hoc analysis, the potential of baseline IL-6 levels to differentially predict the improvement in PRO with sarilumab vs adalimumab in MONARCH. Methods Serum IL-6 levels were measured at baseline in 300/369 patients in the ITT population. Patients were categorized into high, medium, or low IL-6 tertiles levels. Between-group comparisons of differences at Week 24 in Short Form-36 (SF-36) physical and mental component summaries (PCS, MCS) and domain scores, Functional Assessment of Chronic Illness Therapy (FACIT)-fatigue, and morning stiffness visual analog scale (VAS) measures were performed within each tertile using a linear fixed effect model. In order to evaluate the differential effect of sarilumab vs adalimumab in the baseline high vs low IL-6 groups, an interaction test of treatment-by-baseline IL-6 group analysis was performed using low IL-6 group as the reference. Results At baseline, patients in the high IL-6 tertile presented a significantly worse MCS and morning stiffness scores (P Conclusion Evaluation of IL-6 biomarker associations with PROs indicate that patients with high IL-6 levels report better improvements with sarilumab vs adalimumab with safety profile consistent with IL-6R blockade. The effects of adalimumab treatment are stable based on IL-6 tertiles but higher with sarilumab, particularly in the high IL-6 tertile group. Effects on PCS scores are mainly driven by the PF domain, consistent with previous reports of marked improvements in pain with high IL-6 levels. * Significant between-group difference in change from baseline (P SF-36 domains: BP, bodily pain; GH, general health; RP, role-physical, MH, mental health; PF, physical functioning; RE, role emotional; SF, social functioning; VT, vitality. Acknowledgement Medical writing support was provided by Gauri Saal, MA Economics, Prime, Knutsford, UK and funded by Sanofi and Regeneron Pharmaceuticals, Inc. Disclosure of Interests Vibeke Strand Consultant for: AbbVie, Amgen, Bayer, BMS, Boehringer Ingelheim, Celgene, Celltrion, CORRONA, Crescendo, EMD Serono, Genentech/Roche, GSK, Horizon, Inmedix, Janssen, Kezar, Lilly, Merck, Novartis, Pfizer, Regeneron, Samsung, Sandoz, Sanofi, Servier, UCB., Susan Boklage Shareholder of: Regeneron Pharmaceuticals, Inc., Employee of: Regeneron Pharmaceuticals, Inc., Toshio Kimura Shareholder of: Regeneron Pharmaceuticals, Inc., Employee of: Regeneron Pharmaceuticals, Inc., Florence Joly Shareholder of: Sanofi, Employee of: Sanofi, Anita Boyapati Shareholder of: Regeneron Pharmaceuticals, Inc., Employee of: Regeneron Pharmaceuticals, Inc., Jerome Msihid Shareholder of: Sanofi, Employee of: Sanofi

Objective The development of biomarkers to guide treatment decisions is a major research focus in rheumatoid arthritis (RA). Patients with RA have elevated interleukin-6 (IL-6) levels; however, the utility of IL-6 as a predictor of treatment response is unclear. This study was undertaken to investigate, by post hoc analysis, whether baseline IL-6 levels are predictive of sarilumab treatment responses in 2 phase III studies. Methods Serum IL-6 concentrations were measured in patients with RA prior to receiving sarilumab 200 mg (n = 148) or adalimumab 40 mg (n = 152) every 2 weeks (in the MONARCH trial; ClinicalTrials.gov identifier: NCT02332590) or sarilumab 150 mg, sarilumab 200 mg, or placebo every 2 weeks plus methotrexate (MTX) (n = 401, n = 396, and n = 397, respectively) (in the MOBILITY trial; ClinicalTrials.gov identifier: NCT01061736). Efficacy and patient-reported outcomes were compared between and within groups according to IL-6 tertile using linear and logistic regression. Results In MONARCH, patients with high baseline IL-6 levels (all ≥3 times the upper limit of normal; n = 100) had higher disease activity at baseline than those with low IL-6 levels (n = 100). The magnitude of clinical improvement over 24 weeks with sarilumab versus adalimumab was greater in patients with high compared to those with low baseline IL-6 levels. In MOBILITY, compared to patients with low IL-6 levels (n = 397), patients with high IL-6 levels (n = 398) had higher disease activity and joint damage at baseline, were more likely to have joint progression, and had less clinical improvement over 52 weeks' treatment with placebo plus MTX compared to sarilumab 150 mg or 200 mg plus MTX. Baseline IL-6 and C-reactive protein levels were both predictive of outcomes. Safety profiles were similar between defined IL-6 tertiles. Conclusion IL-6 may be a prognostic marker of disease progression and severity, and patients with high IL-6 levels may be likely to benefit from sarilumab compared to adalimumab or MTX. Prospective validation is warranted to confirm the results of these post hoc analyses.

TPS9628 Background: Mesenchymal-epithelial transition (MET) factor is a transmembrane tyrosine kinase receptor activated by hepatocyte growth factor (HGF). Aberrant activation of MET via gene amplification or gene mutations, as well as MET protein overexpression, has been reported in NSCLC and other cancer types and can promote tumorigenesis. REGN5093 is a human bispecific antibody that binds to two distinct epitopes of MET, blocking HGF binding and inducing internalization and degradation of MET. REGN5093 prevents MET-mediated signaling and inhibits growth of MET-driven tumor cells without inducing MET-driven biological responses (DaSilva et al, CCR, 2019; PMID: 31848185). Methods: This Phase I/II, first-in-human, multicenter study is investigating the safety, tolerability, pharmacokinetics (PK), and efficacy of REGN5093 in patients with MET-altered advanced NSCLC who have received all available approved therapies (NCT04077099). Key eligibility criteria include age ≥18 years, Eastern Cooperative Oncology Group performance status of ≤1, and documented presence of either MET exon 14 gene mutation and/or MET gene amplification and/or elevated MET protein expression. Patients are required to provide a biopsy during screening for assessment of MET biomarkers. Key exclusion criteria include prior MET-targeted biologic therapy (expansion cohorts only). Prior therapy with tyrosine kinase inhibitors are not exclusionary in any part of the study. For each patient, the study comprises a screening period of up to 28 days, followed by 3-week cycles of REGN5093 monotherapy. Study treatment will continue until confirmed disease progression or other protocol-defined reason for discontinuation. The study has two parts: dose escalation and dose expansion. Dose escalation will proceed via 4+3 design until a maximum-tolerated dose is reached or a recommended Phase II dose selected. The primary objective of the dose escalation part is to assess safety (incidence and severity of adverse events and Grade ≥3 laboratory abnormalities), tolerability (incidence of dose-limiting toxicities), and PK of REGN5093. During the expansion phase, patients will be allocated to cohorts according to the type(s) of documented biomarkers of MET-altered disease. Anti-tumor activity based on objective response rate per Response Evaluation Criteria in Solid Tumors version 1.1, determined by CT or MRI, will be the primary endpoint in the expansion cohorts. The study is currently open for enrollment. Clinical trial information: NCT04077099 .

Background Two studies (PDY14191 [NCT02404558]: randomised, open-label, Japanese patients; 6R88-RA-1309 [NCT02097524]: randomised, open-label, non-Japanese patients) assessed the pharmacodynamic profiles of two monoclonal antibody blockers of IL-6Rα, sarilumab and tocilizumab. Objectives To evaluate the pharmacodynamics of absolute neutrophil count (ANC), C-reactive protein (CRP), IL-6, soluble IL-6R (sIL-6R), and safety after a single dose of subcutaneous (SC) sarilumab, or intravenous (IV) or SC tocilizumab in patients with RA. Methods 30 Japanese patients (PDY14191) were randomised 1:1 and received a single injection with SC sarilumab 150 mg or SC tocilizumab 162 mg without background medication. 101 non-Japanese patients (6R88-RA-1309) were randomised 1:1:1:1 and received a single dose of SC sarilumab (150 or 200 mg)+methotrexate (MTX), or IV tocilizumab (4 or 8 mg/kg)+MTX. Pharmacodynamic and safety outcomes were assessed through Week 6. Results Baseline demographics were comparable between studies except for higher mean body weight in non-Japanese patients (mean 83 vs 57 kg). Although there were numeric differences in baseline pharmacodynamic parameters in the two studies, onset of effects on ANC, CRP, IL-6, and sIL-6R during the first week after a single drug dose were similar regardless of drug, dose, or route of administration in both studies. Within both studies, maximal effects on ANC and CRP nadir and on IL-6 and total sIL6-R peaks were comparable for sarilumab and tocilizumab (table 1). The pharmacodynamic response was more prolonged with IV tocilizumab. Time for pharmacodynamic effects to return to baseline was consistent with the dosing intervals for SC sarilumab (q2w), and IV (q4w) and SC (q2w) tocilizumab. The safety profiles of sarilumab and tocilizumab were generally similar and both drugs were associated with laboratory effects consistent with their mechanism of action (ie, decrease in neutrophil count). There was a dose-dependent effect on ANC Conclusions The pharmacodynamic and safety profiles observed after a single-dose of sarilumab SC or IV/SC tocilizumab are consistent with results anticipated in patients with RA administered an IL–6R inhibitor. Acknowledgements Study funding and medical writing support (Julie Grey, Adelphi Group) was provided by Sanofi and Regeneron Pharmaceuticals, Inc. Disclosure of Interest T. Ishii Paid instructor for: GSK, Janssen, Speakers bureau: Mitsubishi-Tanabe, Janssen, Chugai, Ono, Sanofi, Abbvie, Eisai, Astellas, UCB, Teijin, Daiichi-Sankyo, Pfizer, Takeda, Asahi Kasei Pharma, Y. Sato Consultant for: SRL, Paid instructor for: Bristol-Myers Squibb, Y. Munakata: None declared, M. Kajiwara Employee of: Sanofi K.K., Y. Takahashi Employee of: Sanofi K.K., F. Anwar Employee of: Sanofi, A. Paccaly Shareholder of: Regeneron, Sanofi, Amgen, Employee of: Regeneron, P. Kovalenko Shareholder of: Regeneron, Employee of: Regeneron, J. Parrino Shareholder of: Regeneron, Employee of: Regeneron, A. Boyapati Shareholder of: Regeneron Pharmaceuticals, Employee of: Regeneron Pharmaceuticals, C. Xu Shareholder of: Sanofi, Employee of: Sanofi

Introduction Interleukin-6 (IL-6) orchestrates formation of an inflammatory pannus, leading to joint damage in rheumatoid arthritis (RA). Sarilumab is a human monoclonal antibody blocking the IL-6Rα. In TARGET (NCT01709578), a phase 3 study in adults with moderate-to-severe RA and inadequate response or intolerance to tumour necrosis factor inhibitors, subcutaneous sarilumab 200 mg or 150 mg every 2 weeks (q2w) plus conventional synthetic disease-modifying antirheumatic drugs (csDMARDs) significantly reduced disease activity versus placebo plus csDMARDs. Methods Circulating levels of biomarkers associated with synovial inflammation (matrix metalloproteinase 3 (MMP-3), collagen type I MMP-cleaved fragment (C1M), collagen type III MMP-cleaved fragment (C3M)), myeloid (soluble intercellular adhesion molecule 1 (sICAM-1), IL-8 and calprotectin) and lymphoid activation (chemokine, CXC motif, ligand 13 (CXCL13), CXCL10, B cell-activating factor) and bone remodelling (receptor activator of nuclear factor-κB ligand (RANKL), osteoprotegerin and osteocalcin) were evaluated in patients from a TARGET substudy. Results Sarilumab significantly decreased C1M, C3M, CXCL13, MMP-3 and total RANKL levels at week 24 versus placebo; some markers were significantly suppressed at week 2 and normalised to levels in healthy controls. Levels of sICAM-1 were predictive of disease activity score by C-reactive protein and clinical disease activity index low disease activity (LDA) response in the sarilumab 200 mg q2w group at week 12. A trend was observed in which patients with lower sICAM-1 levels at baseline had better response compared with patients with higher sICAM-1. Conclusions Sarilumab plus csDMARDs decreased circulating biomarkers of synovial inflammation and bone resorption; sICAM-1 was predictive of achieving LDA with sarilumab. Trial registration number NCT01709578; Post-results.

Background Sarilumab is a human mAb that blocks IL-6 from binding to both membrane-bound and soluble IL-6Rα (sIL-6R). A missense variant in the IL6R gene, Asp358Ala (rs2228145), falls within a proteolytic cleavage site and individuals with an alanine at this position have increased sIL-6R in circulation. 1 In addition, this variant has been associated with several diseases including RA. 2 Objectives To determine the impact of the Asp358Ala variant on sIL-6R concentrations and response of RA patients to sarilumab. Methods DNA was collected from patients enrolled in the MOBILITY study (NCT01061736) that evaluated the efficacy and safety of sarilumab + methotrexate (MTX) in RA patients with inadequate response to MTX. The pharmacogenetic analysis was conducted on 599 Caucasian patients (396 sarilumab 150 or 200 mg q2w + MTX, 203 placebo + MTX). Results Concentrations of sIL-6R were strongly associated with the Asp358Ala genotypes at baseline ( p =4.2 × 10 -11 ). The difference in sIL-6R concentrations between genotype groups continued to increase in sarilumab-treated patients through the end of treatment, particularly for the CC genotype (Figure; p =7.8 × 10 -12 ). There was a modest association for change in sIL-6R in placebo + MTX–treated patients ( p =0.0052). Variation in Asp358Ala was not associated with sarilumab efficacy, including mTSS at week 52 and ACR scores (Table). Conclusions The Asp358Ala variant in the IL6R gene is significantly associated with differences in sIL-6R levels at baseline and after sarilumab treatment. The differences across genotypes may be due to increases in sIL-6R production. Importantly, this variant was not associated with differences in sarilumab treatment response. These data suggest that the sarilumab doses used for this clinical study saturate both the membrane and soluble forms of IL-6R and effectively block IL-6 signaling. Sarilumab provides therapeutic benefit for RA patients irrespective of their Asp358Ala genotype status. References Garbers et al. Biochim Biophys Acta. 2014;1842:1485–1494. Okada et al. Nature. 2014;506:376–381. Acknowledgements This study was sponsored by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Editorial support was provided by MedThink SciCom and funded by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Disclosure of Interest A. Damask Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Boyapati Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Hamilton Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, S. Hamon Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, C. Paccard Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, J. Parrino Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. van Adelsberg Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, N. Graham Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Penn Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Lopez Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Reid Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Overton Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Baras Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Shuldiner Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, C. Paulding Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc

Background MONARCH (NCT02332590) was a randomized, active-controlled, double-blind, double-dummy, phase 3 superiority trial comparing sarilumab monotherapy with adalimumab monotherapy. Exploratory biomarkers associated with inflammation, bone erosion, and cardiovascular (CV) risk were evaluated in this study. Objectives To compare the effects of sarilumab monotherapy vs adalimumab monotherapy on circulating biomarkers associated with acute-phase response (CRP, serum amyloid A [SAA]), bone resorption (RANKL and osteoprotegerin [OPG]), and CV risk (lipoprotein (a) [Lp(a)]) in patients from MONARCH. Methods Sera were analyzed at baseline and posttreatment through wk 24 from patients who consented to biomarker analyses and received SC sarilumab 200 mg q2w (N=153) or adalimumab 40 mg q2w (N=154). Biomarkers were assessed using validated ELISAs. Nonparametric methods were used to evaluate differences in the percent change from baseline in biomarker levels between treatments at each time point. Percent change from baseline in biomarkers at wk 24 was also compared, separately by treatment group, between ACR50 responders and nonresponders at wk 24. The Benjamini-Hochberg procedure was used to correct P values for multiplicity and control false discovery rate. Significance level was P Results A significant difference in RANKL was observed at wks 2 and 24 between sarilumab and adalimumab groups (P At wk 24, change in OPG, RANKL, and Lp(a) did not differ between ACR50 responders and nonresponders at wk 24 in either treatment group. Responders in both groups demonstrated greater reductions vs nonresponders in CRP (sarilumab, -95.8% vs -87.3%; adalimumab, -47.6% vs -6.4%; all P Conclusions Sarilumab monotherapy significantly suppressed bone-resorptive and CV risk markers to a greater degree than adalimumab monotherapy. Reductions in CRP were significantly different in ACR50 responders vs nonresponders after either treatment. Analyses to assess predictive and prognostic effects of biomarkers (including markers of myeloid and lymphoid synovial phenotypes) are ongoing. Acknowledgements This study was sponsored by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Editorial support was provided by MedThink SciCom and funded by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Disclosure of Interest C. Gabay Consultant for: Roche, Merck, AbbVie, Pfizer, Bristol-Myers Squibb, Sanofi-Aventis, and AB2 Bio, J. Msihid Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, C. Paccard Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, M. Zilberstein Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, N. Graham Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Boyapati Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc

Background Sarilumab is a human mAb that blocks IL-6 from binding to both membrane-bound and soluble IL-6Rα. Variants in the UGT1A1 gene have been shown to be strongly associated with increased unconjugated bilirubin levels in patients treated with tocilizumab, another IL-6Rα inhibitor.1,2UGT1A1 encodes the enzyme responsible for the glucuronidation of bilirubin and variation in this gene is also responsible for Gilbert9s syndrome, a mild benign condition characterized by elevations in unconjugated bilirubin and jaundice. The underlying main genetic variation responsible for Gilbert9s syndrome has been identified as a TA repeat located in the promoter of UGT1A1 (UGT1A1*28 allele), which is in linkage disequilibrium with a single nucleotide polymorphism, rs6742078, previously associated with higher bilirubin levels after tocilizumab treatment.1 Objectives To test for an association between rs6742078 and bilirubin levels in RA patients treated with sarilumab. Methods DNA was collected from patients enrolled in MOBILITY (NCT01061736), which evaluated the efficacy and safety of sarilumab + methotrexate (MTX) in RA patients with inadequate response to MTX. The pharmacogenetic analysis was conducted in 599 Caucasian patients treated with MTX + sarilumab (150 or 200 mg q2w) or placebo. Log-transformed unconjugated and total bilirubin levels were analyzed at baseline and over the treatment period (using maximum bilirubin). Results There was a strong association between the rs6742078 TT genotype and higher unconjugated bilirubin levels. The least squares mean (SE) for patients at baseline with the TT genotype was 0.48 (0.02) mg/dL vs 0.25 (0.009) and 0.21 (0.009) mg/dL for those with GT and GG genotypes, respectively (p=1.02×10-21). After sarilumab treatment, the difference between genotype groups increased over the course of the study (p=4.3×10-10; Figure). In the binary analysis of maximum total bilirubin in sarilumab-treated patients, the TT genotype was significantly associated with mild bilirubin elevations (OR =34.7; p=1.2×10-8; Table). Conclusions The association observed between the rs6742078 TT genotype in UGT1A1 and unconjugated bilirubin elevations in sarilumab-treated patients is consistent with previous observations in tocilizumab-treated patients. These findings suggest that sarilumab-related increases in bilirubin levels are likely benign and caused by common genetic variation in UGT1A1 and are not due to underlying liver injury. References Mori et al. Mod Rheumatol. 2012;22:515–523. Lee et al. Pharmacogenet Genomics. 2011;21:365–374. Acknowledgements This study was sponsored by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Editorial support was provided by MedThink SciCom and funded by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Disclosure of Interest A. Damask Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Boyapati Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Hamilton Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, S. Hamon Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, C. Paccard Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, J. Parrino Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. van Adelsberg Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, N. Graham Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Penn Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Lopez Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Reid Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, J. Overton Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Baras Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, A. Shuldiner Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, C. Paulding Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc

Background Bone and joint damage due to chronic inflammation in the synovium of patients with RA is mediated by IL-6 and other cytokines. IL-6 mediates effects inside the joint and systemically and is blocked by sarilumab, a human mAb blocking the IL-6R?. Safety and efficacy of SC sarilumab (150 or 200 mg q2w) was evaluated in combination with MTX in patients with RA and inadequate response (IR) to MTX (MOBILITY; NCT01061736) or csDMARDs in patients with RA and IR or intolerance to ≥1 TNFi (TARGET; NCT01709578). Objectives To compare gene expression patterns in circulating blood cells after treatment with sarilumab vs placebo in patients from MOBILITY and TARGET. Methods Total RNA was isolated from whole blood collected at baseline (predose) and wk 2 posttreatment in patients from MOBILITY (placebo, n=58; sarilumab 150 mg q2w, n=60; sarilumab 200 mg q2w, n=46) and TARGET (placebo, n=19; sarilumab 150 mg q2w, n=27; sarilumab 200 mg q2w, n=16). Gene expression data were generated using microarray analyses (Agilent 8 × 60k platform). Data were processed using the limma package (R Bioconductor). Background correction and quantile normalization were performed and probes with low expression were filtered; 48,109 probes were analyzed. Effect of sarilumab vs placebo on gene expression was assessed in each study using linear mixed models. P values were adjusted using the Benjamini-Hochberg procedure to control false discovery rate (FDR; 5% threshold). Results After P value adjustment to control FDR at 5%, 2 genes implicated in thrombosis and atherosclerosis (thrombomodulin [THBD] and platelet endothelial cell adhesion molecule 1 [PECAM-1]) were downregulated after treatment with sarilumab 200 mg q2w vs placebo in both studies (Table). These genes decreased with a fold-change (FC) ≤0.8 in both studies (P Conclusions In patients with active RA, sarilumab may decrease thrombosis-related gene expression in circulating immune cells. Additional analysis of the serum levels of thrombosis risk proteins is needed to test the hypothesis that sarilumab treatment decreases levels of thrombosis risk factors. Acknowledgements This study was sponsored by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Editorial support was provided by MedThink SciCom and funded by Sanofi Genzyme and Regeneron Pharmaceuticals, Inc. Disclosure of Interest C. Paccard Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, J. Msihid Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, A. Brisacier Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, A. Damask Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, C. Paulding Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc, M. Zilberstein Shareholder of: Sanofi R&D, Employee of: Sanofi R&D, A. Boyapati Shareholder of: Regeneron Pharmaceuticals, Inc, Employee of: Regeneron Pharmaceuticals, Inc

Interleukin 6 (IL-6) signaling plays a key role in the pathophysiology of rheumatoid arthritis (RA) and is inhibited by sarilumab, a human monoclonal antibody blocking the IL-6 receptor alpha (IL-6Rα). The effects of sarilumab plus methotrexate (MTX) on serum biomarkers of joint damage and bone resorption were assessed in two independent studies (phase II (part A) and phase III (part B)) of patients with RA with a history of inadequate response to MTX from the MOBILITY study (NCT01061736). Serum samples were analyzed at baseline and prespecified posttreatment time points. Biomarkers of tissue destruction, cartilage degradation, and synovial inflammation were measured in part A; assessment of these markers was repeated in part B and included additional analysis of biomarkers of bone formation and resorption (including soluble receptor activator of nuclear factor-kB ligand (sRANKL)). A mixed model for repeated measures was used to compare treatment effects on change in biomarkers. Additionally, changes from baseline in biomarkers were compared between American College of Rheumatology 50 % responders and nonresponders and between patients who achieved or did not achieve low disease activity (LDA), separately by treatment group, at week 24. In part A, sarilumab 150 and 200 mg every 2 weeks (q2w) significantly reduced biomarkers of tissue destruction, cartilage degradation, and synovial inflammation at both 2 and 12 weeks posttreatment (p

RUNX1 is a critical transcription factor during embryogenesis and neoplastic disease. To identify novel transcriptional targets of RUNX1 in the context of chromatin, we performed genome wide location analysis (ChIP-on-chip). Here we report that SERPINB13, a gene downregulated in head and neck cancers, is a novel RUNX1transcriptional target. RUNX1 binds the SERPINB13 promoter in chromatin to repress its transcription. Mutation of either RUNX1 binding site in the SERPINB13 promoter increased the activity of the promoter. Finally, overexpression of RUNX1 and concomitant decrease in SERPINB13 expression led to increased activity of cathepsin K, an enzyme inhibited by SERPINB13. These data demonstrate that RUNX1 is an important regulator of SERPINB13 and cathepsin K activity.

It has been suspected that cell cycle progression might be functionally coupled with RNA processing. However, little is known about the role of the precise splicing control in cell cycle progression. Here, we report that SON, a large Ser/Arg (SR)-related protein, is a splicing co-factor contributing to efficient splicing of cell cycle regulators. Down-regulation of SON leads to severe impairment of spindle pole separation, microtubule dynamics, and genome integrity. These molecular defects result from inadequate RNA splicing of a specific set of cell cycle-related genes that possess weak splice sites. Furthermore, we show that SON facilitates the interaction of SR proteins with RNA polymerase II and other key spliceosome components, suggesting its function in efficient co-transcriptional RNA processing. These results reveal a mechanism for controlling cell cycle progression through SON-dependent constitutive splicing at suboptimal splice sites, with strong implications for its role in cancer and other human diseases.

Engagement of cell surface receptor tyrosine kinases by insulin and growth factors activates phosphatidylinositol 3-kinase (PI3K) and generates the second messenger, phosphatidylinositol 3,4,5-trisphosphate. This second messenger leads to the recruitment of 3-phosphoinositide–dependent protein kinase-1 (PDK1) to the proximal side of the plasma membrane, which results in the activation of AKT kinase. In addition, PDK1 can phosphorylate numerous other kinases, including p90RSK, a kinase downstream of mitogen-activated protein kinase (MAPK) that is important for cell proliferation and survival. Previous studies have shown that the loss of PDK1 sensitizes tumor cells to chemotherapeutic agents and radiation but have not focused on delineating the contribution of PDK1 to pathway-specific mutations associated with various cancers other than the PI3K/AKT pathway. In this study, we show that the reduction of PDK1 by RNAi in melanoma and colon cancer cell lines activated in the MAPK pathway results in significant cell growth inhibition and apoptosis. Furthermore, PDK1 reduction in tumor cells resulted in impaired PAK kinase signaling, altered actin polymerization, and reduced cell migration. These studies show that PDK1 plays a pivotal role in MAPK and PI3K signaling in tumor cells. Mol Cancer Res; 8(3); 421–32

Nonrandom and somatically acquired chromosomal translocations can be identified in nearly 50% of human acute myeloid leukemias. One common chromosomal translocation in this disease is the 8q22;21q22 translocation. It involves the AML1 (RUNX1) gene on chromosome 21 and the ETO (MTG8, RUNX1T1) gene on chromosome 8 generating the AML1-ETO fusion proteins. In this review, we survey recent advances made involving secondary mutational events and alternative t(8;21) transcripts in relation to understanding AML1-ETO leukemogenesis.

The family of cyclin D proteins plays a crucial role in the early events of the mammalian cell cycle. Recent studies have revealed the involvement of AML1 transactivation activity in promoting cell cycle progression through the induction of cyclin D proteins. This information in combination with our previous observation that a region in AML1 between amino acids 213 and 289 is important for its function led us to investigate prospective proteins associating with this region. We identified cyclin D3 by a yeast two-hybrid screen and detected AML1 interaction with the cyclin D family by both in vitro pull-down and in vivo coimmunoprecipitation assays. Furthermore, we demonstrate that cyclin D3 negatively regulates the transactivation activity of AML1 in a dose-dependent manner by competing with CBFbeta for AML1 association, leading to a decreased binding affinity of AML1 for its target DNA sequence. AML1 and its fusion protein AML1-ETO have been shown to shorten and prolong the mammalian cell cycle, respectively. In addition, AML1 promotes myeloid cell differentiation. Thus, our observations suggest that the direct association of cyclin D3 with AML1 functions as a putative feedback mechanism to regulate cell cycle progression and differentiation.

Transformation of human cells requires both SV40 large T and small t antigens. Plasmids that contained mutations in the amino-terminal dnaJ domain of the early region fail to transform human diploid fibroblasts. However, large T dnaJ mutants can be rescued by plasmids that express early region products other than large T antigen. The protein found to be responsible for such complementation was the third early region product, 17KT. Similar to large T, this protein reduces levels of the retinoblastoma-related protein, p130, and stimulates cell-cycle progression of quiescent fibroblasts, two activities of large T that are disrupted by dnaJ mutations.

Defining the ability of simian virus 40 (SV40) to transform human cells has become of even greater importance with the increased understanding that this virus may play a role in some human malignancies. This report documents the requirement for viral small-t (ST) antigen in large-T (LT)-driven transformation of primary fibroblasts, a requirement that cannot be met by a well-known oncogene, c-Ha-ras (EJ-ras), which can cooperate with LT in rodent systems. The cellular gene telomerase is not essential for transformation, although transformed clones are not immortal without it. Similarly, an immortal mesothelial cell line has been developed using LT and telomerase. Immortalized mesothelial cells are morphologically normal, but can be transformed by introduction of ST, or ST + ras, but not by ras alone. It is likely that ST will be required along with LT for transformation of most human cell types.

Udgivelsesdato: 2008-Nov-4 AML1-ETO is generated from t(8;21)(q22;q22), which is a common form of chromosomal translocation associated with development of acute myeloid leukemia (AML). Although full-length AML1-ETO alone fails to promote leukemia because of its detrimental effects on cell proliferation, an alternatively spliced isoform, AML1-ETO9a, without its C-terminal NHR3/NHR4 domains, strongly induces leukemia. However, full-length AML1-ETO is a major form of fusion product in many t(8;21) AML patients, suggesting additional molecular mechanisms of t(8;21)-related leukemogenesis. Here, we report that disruption of the zinc-chelating structure in the NHR4 domain of AML1-ETO by replacing only one critical amino acid leads to rapid onset of leukemia, demonstrating that the NHR4 domain with the intact structure generates inhibitory effects on leukemogenesis. Furthermore, we identified SON, a DNA/RNA-binding domain containing protein, as a novel NHR4-interacting protein. Knock-down of SON by siRNA resulted in significant growth arrest, and disruption of the interaction between AML1-ETO and endogenous SON rescued cells from AML1-ETO-induced growth arrest, suggesting that SON is an indispensable factor for cell growth, and AML1-ETO binding to SON may trigger signals inhibiting leukemogenesis. In t(8;21) AML patient-derived primary leukemic cells and cell lines, abnormal cytoplasmic localization of SON was detected, which may keep cells proliferating in the presence of full-length AML1-ETO. These results uncovered the crucial role of the NHR4 domain in determination of cellular fate during AML1-ETO-associated leukemogenesis.

Chromosome abnormalities are frequently associated with cancer development. The 8;21(q22;q22) chromosomal translocation is one of the most common chromosome abnormalities identified in leukemia. It generates fusion proteins between AML1 and ETO. Since AML1 is a well-defined DNA-binding protein, AML1-ETO fusion proteins have been recognized as DNA-binding proteins interacting with the same consensus DNA-binding site as AML1. The alteration of AML1 target gene expression due to the presence of AML1-ETO is related to the development of leukemia. Here, using a 25-bp random double-stranded oligonucleotide library and a polymerase chain reaction (PCR)-based DNA-binding site screen, we show that compared with native AML1, AML1-ETO fusion proteins preferentially bind to DNA sequences with duplicated AML1 consensus sites. This finding is further confirmed by both in vitro and in vivo DNA-protein interaction assays. These results suggest that AML1-ETO fusion proteins have a selective preference for certain AML1 target genes that contain multimerized AML1 consensus sites in their regulatory elements. Such selected regulation provides an important molecular mechanism for the dysregulation of gene expression during cancer development.

The 8;21 chromosomal translocation occurs in 15% to 40% of patients with the FAB M2 subtype of acute myeloid leukemia (AML). This chromosomal abnormality fuses part of the AML1/RUNX1 gene to the ETO/MTG8 gene and generates the AML1-ETO protein. We previously identified a C-terminal truncated AML1-ETO protein (AEtr) in a mouse leukemia model. AEtr is almost identical to the AML1-ETO exon 9a isoform expressed in leukemia patients. Here, we describe a novel function of AEtr in the development of aneuploidy through spindle checkpoint attenuation. AEtr cells had a reduced mitotic index following nocodazole treatment, suggesting a failure in a subset of cells to arrest in mitosis with a functional spindle checkpoint. Additionally, primary leukemia cells and cell lines expressing AEtr were aneuploid. Moreover, AEtr cells had reduced levels of several spindle checkpoint proteins including BubR1 and securin following treatment with the spindle poison nocodazole. These results suggest that inactivation of the spindle checkpoint may contribute to the development of aneuploidy described in t(8;21) leukemia patients.