A. Godwood

Efficacy and safety of mavrilimumab in subjects with rheumatoid arthritis

Objectives Mavrilimumab, a human monoclonal antibody targeting the alpha subunit of the granulocyte-macrophage colony-stimulating factor receptor, was evaluated in a phase 2 randomised, double-blind, placebo-controlled study to investigate efficacy and safety in subjects with rheumatoid arthritis (RA). Methods Subcutaneous mavrilimumab (10 mg, 30 mg, 50 mg, or 100 mg) or placebo was administered every other week for 12 weeks in subjects on stable background methotrexate therapy. The primary endpoint was the proportion of subjects achieving a ≥1.2 decrease from baseline in Disease Activity Score (DAS28-CRP) at week 12. Results 55.7% of mavrilimumab-treated subjects met the primary endpoint versus 34.7% placebo (p=0.003) at week 12; for the 10 mg, 30 mg, 50 mg, and 100 mg groups, responses were 41.0% (p=0.543), 61.0% (p=0.011), 53.8% (p=0.071), and 66.7% (p=0.001) respectively. Response rate differences from placebo were observed at week 2 and increased throughout the treatment period. The 100 mg dose demonstrated a significant effect versus placebo on DAS28-CRP<2.6 (23.1% vs 6.7%, p=0.016), all categories of the American College of Rheumatology (ACR) criteria (ACR20: 69.2% vs 40.0%, p=0.005; ACR50: 30.8% vs 12.0%, p=0.021; ACR70: 17.9% vs 4.0%, p=0.030), and the Health Assessment Questionnaire Disability Index (−0.48 vs −0.25, p=0.005). A biomarker-based disease activity score showed a dose-dependent decrease at week 12, indicating suppression of disease-related biological pathways. Adverse events were generally mild or moderate in intensity. No significant hypersensitivity reactions, serious or opportunistic infections, or changes in pulmonary parameters were observed. Conclusions Mavrilimumab induced rapid clinically significant responses in RA subjects, suggesting that inhibiting the mononuclear phagocyte pathway may provide a novel therapeutic approach for RA.

A randomised phase IIb study of mavrilimumab, a novel GM–CSF receptor alpha monoclonal antibody, in the treatment of rheumatoid arthritis

Objectives Despite the therapeutic value of current rheumatoid arthritis (RA) treatments, agents with alternative modes of action are required. Mavrilimumab, a fully human monoclonal antibody targeting the granulocyte–macrophage colony-stimulating factor receptor-α, was evaluated in patients with moderate-to-severe RA. Methods In a phase IIb study (NCT01706926), patients with inadequate response to ≥1 synthetic disease-modifying antirheumatic drug(s), Disease Activity Score 28 (DAS28)−C reactive protein (CRP)/erythrocyte sedimentation rate ≥3.2, ≥4 swollen joints despite methotrexate (MTX) were randomised 1:1:1:1 to subcutaneous mavrilimumab (150, 100, 30 mg), or placebo every other week (eow), plus MTX for 24 weeks. Coprimary outcomes were DAS28−CRP change from baseline to week 12 and American College of Rheumatology (ACR) 20 response rate (week 24). Results 326 patients were randomised (150 mg, n=79; 100 mg, n=85; 30 mg, n=81; placebo, n=81); 305 completed the study (September 2012–June 2013). Mavrilimumab treatment significantly reduced DAS28−CRP scores from baseline compared with placebo (change from baseline (SE); 150 mg: −1.90 (0.14), 100 mg: −1.64 (0.13), 30 mg: −1.37 (0.14), placebo: −0.68 (0.14); p<0.001; all dosages compared with placebo). Significantly more mavrilimumab-treated patients achieved ACR20 compared with placebo (week 24: 73.4%, 61.2%, 50.6% vs 24.7%, respectively (p<0.001)). Adverse events were reported in 43 (54.4%), 36 (42.4%), 41 (50.6%) and 38 (46.9%) patients in the mavrilimumab 150, 100, 30 mg eow and placebo groups, respectively. No treatment-related safety signals were identified. Conclusions Mavrilimumab significantly decreased RA disease activity, with clinically meaningful responses observed 1 week after treatment initiation, representing a novel mechanism of action with persuasive therapeutic potential. Trial registration number NCT01706926; results.

Efficacy and safety of mavrilimumab in Japanese subjects with rheumatoid arthritis: Findings from a Phase IIa study

Abstract Objective. A phase IIa study investigated efficacy and safety/tolerability of ascending doses of mavrilimumab (anti-granulocyte-macrophage colony-stimulating factor receptor [GM-CSFR]α monoclonal antibody) in adult subjects with moderate to severe rheumatoid arthritis from Japan and Europe. Findings from the Japanese population are presented. Methods. Fifty-one subjects received mavrilimumab (10–100 mg) or placebo subcutaneously every other week for 12 weeks, followed by a 12-week follow-up period. The primary endpoint was the proportion of subjects achieving a Disease Activity Score using 28 joints (DAS28)-C-reactive protein (CRP) response (decrease > 1.2 from baseline). Secondary endpoints included DAS28-CRP remission, Health Assessment Questionnaire Disability Index (HAQ-DI) and American College of Rheumatology (ACR) response. Results. By Week 12, more mavrilimumab- versus placebo-treated subjects achieved a DAS28-CRP response (50.0% vs. 23.5%, p = 0.081); a significant response was seen in the 30 mg and 100 mg dose groups (both 75.0% vs. 23.5%, p = 0.028). The 100 mg group also demonstrated statistically significant HAQ-DI and ACR20 responses at Week 12. Results were generally consistent between Japanese and European populations. Overall, adverse events (AEs) were mild to moderate in intensity with one serious AE of pneumonia, considered possibly treatment-related. Conclusions. A rapid and clinically meaningful response was seen in subjects treated with GM-CSFRα blockade with mavrilimumab, supporting further investigation of mavrilimumab for the treatment of RA in Japanese subjects.

A Randomized Phase IIb Study of Mavrilimumab and Golimumab in Rheumatoid Arthritis

This 24‐week, phase IIb, double‐blind study was undertaken to evaluate the efficacy and safety of mavrilimumab (a monoclonal antibody to granulocyte–macrophage colony‐stimulating factor receptor α) and golimumab (a monoclonal antibody to tumor necrosis factor [anti‐TNF]) in patients with rheumatoid arthritis (RA) who have had an inadequate response to disease‐modifying antirheumatic drugs (DMARDs) (referred to as DMARD‐IR) and/or inadequate response to other anti‐TNF agents (referred to as anti‐TNF–IR).

Mavrilimumab, a Fully Human Granulocyte-Macrophage Colony-Stimulating Factor Receptor α Monoclonal Antibody: Long-Term Safety and Efficacy in Patients With Rheumatoid Arthritis

Mavrilimumab, a human monoclonal antibody, targets granulocyte–macrophage colony‐stimulating factor receptor α. We undertook to determine the long‐term safety and efficacy of mavrilimumab in rheumatoid arthritis patients in 2 phase IIb studies (1071 and 1107) and in 1 open‐label extension study (ClinicalTrials.gov identifier: NCT01712399).

OP0034 Efficacy and Safety of Mavrilimumab, A Fully Human Gm–CSFR-Alpha Monoclonal Antibody in Patients with Rheumatoid Arthritis: Primary Results from the Earth Explorer 1 Study

Background Of patients with RA, ∼40% of do not achieve a minimal acceptable improvement (ACR20) despite modern biologic therapy.1,2,3 Granulocyte-macrophage colony-stimulating factor (GM–CSF) is implicated in RA pathogenesis via myeloid and granulocyte cell lineage activation. In a 12-week Phase IIa study, mavrilimumab, a first-in-class inhibitor of the GM–CSF receptor-α demonstrated a sustained effect via this novel therapeutic pathway in RA.4 Objectives To evaluate the efficacy and safety of mavrilimumab in patients with moderate to severe, adult-onset RA in a 24-week, Phase IIb study. Methods Patients (18–80 yrs; inadequate response to ≥1 DMARDs; DAS28–CRP ≥3.2; ≥4 SJC) receiving MTX were randomized to receive 1 of 3 SC mavrilimumab dosages (150, 100, 30 mg every other week [eow]) or placebo (PBO) plus MTX (7.5–25.0 mg/week). Co-primary endpoints were change in DAS28–CRP (Day 1 to Week 12) and ACR20 response rate (Week 24). Safety and tolerability were measured through assessment of AEs and pulmonary parameters. Results were analyzed using the modified ITT population. Results 326 patients from Europe, South America, and South Africa (mean [SD] age, 51.8 [11.1] yrs; female, 86.5%; mean [SD] DAS28–CRP, 5.8 [0.9]; RF+/anti-CCP+, 81.9%) received mavrilimumab 150, 100 or 30 mg eow or PBO (N=79, 85, 81 and 81, respectively). At Week 12, a statistically significant difference in DAS28–CRP change from baseline (p<0.001) was observed for all dosages of mavrilimumab vs. PBO. At Week 24, a significantly greater percentage of all mavrilimumab-treated patients also met the ACR20 co-primary endpoint vs. PBO (table). A dosage response was observed across several secondary endpoints, with separation from PBO evident as early as Week 1 and first dose. The most common treatment-emergent AEs were headache (7.6%, 4.7%, 6.2%, 2.5%), nasopharyngitis (7.6%, 3.5%, 4.9%, 7.4%) and bronchitis (5.1%, 1.2%, 3.7%, 7.4%) for mavrilimumab 150, 100, 30 mg eow or PBO, respectively. There was no increase in pulmonary AEs for mavrilimumab vs. PBO (6.3%, 3.5%, 6.2% vs. 9.9%). No serious infections were observed in the 100 and 150 mg eow groups. Two cases of pneumonia were observed (one each in mavrilimumab 30 mg eow and PBO groups). There were no deaths or anaphylaxis, and no apparent dosage relationship for AEs. >90% of patients entered a long-term, open-label extension study. Conclusions This Phase IIb study demonstrated the potential benefit of inhibiting macrophage activity via the GM–CSF receptor-α pathway on RA disease activity. The study met both co-primary endpoints with a clear dosage response. Mavrilimumb was well-tolerated over the 24-week study period. References Weinblatt ME, et al. N Engl J Med 1999;340:253–9. Lipsky PE, et al. N Engl J Med 2000;343:1594–602. Weinblatt ME, et al. Arthritis Rheum 2003;48:35–45, Burmester GR, et al. Ann Rheum Dis 2013;72:1445–52. Acknowledgements Funded: MedImmune. Editorial assistance: N Panagiotaki, QXV Communications, UK †Joint senior authors. Disclosure of Interest G. Burmester Grant/research support from: AbbVie, Pfizer, UCB, Roche, Consultant for: AbbVie, BMS, Novartis, MedImmune, MSD, Pfizer, UCB, Roche, Speakers bureau: AbbVie, BMS, Novartis, MSD, Pfizer, UCB, Roche, I. McInnes Grant/research support from: MedImmune (Research award to University of Glasgow), Consultant for: MedImmune, AstraZeneca, J. Kremer Shareholder of: Corrona, Grant/research support from: AbbVie, Amgen, Genentech, Lilly, Pfizer, Consultant for: AbbVie, Amgen, Genentech, Lilly, Pfizer, BMS, Employee of: Corrona, P. Miranda Grant/research support from: MedImmune (to support protocol), M. Korkosz: None declared, J. Vencovsky: None declared, A. Rubbert-Roth Grant/research support from: Pfizer, Chugai, Consultant for: MSD, USB, Abbott, Pfizer, Roche, BMS, Chugai, Speakers bureau: Roche, Pfizer, UCB, E. Mysler Grant/research support from: Medimmune, Roche, BMS, Pfizer, M. Sleeman Shareholder of: AstraZeneca, Employee of: MedImmune, A. Godwood Shareholder of: AstraZeneca, Employee of: MedImmune, M. Albulescu Employee of: MedImmune, D. Close Shareholder of: AstraZeneca, Employee of: MedImmune, M. Weinblatt Grant/research support from: BMS, UCB, Crescendo Bioscience, Consultant for: MedImmune, AstraZeneca, Amgen, Abbvie, BMS, Crescendo Bioscience, Lilly, Pfizer, UCB, Roche

SAT0146 Earth Explorer 2, A Phase IIB Exploratory Study Evaluating Efficacy and Safety of Mavrilimumab, A Fully Human Granulocyte-Macrophage Colony-Stimulating Factor Receptor-Alpha Monoclonal Antibody, and The Tumor Necrosis Factor Antagonist Golimumab in Rheumatoid Arthritis

Background Mavrilimumab, a fully human monoclonal antibody targeting the granulocyte-macrophage colony-stimulating factor receptor-α, has demonstrated efficacy and safety in disease-modifying antirheumatic drug (DMARD)-inadequate responder (IR) patients (pts) with rheumatoid arthritis (RA).1 Objectives Few head-to-head studies in tumor necrosis factor antagonist (aTNF)-IR assess alternative aTNFs vs. other agents; this Phase IIb exploratory study (NCT01715896) evaluates the efficacy and safety of mavrilimumab and golimumab in aTNF-IR and DMARD-IR pts. Methods This 24-week study enrolled pts with active RA (28-joint Disease Activity Score [DAS28]–C-reactive protein [CRP]/erythrocyte sedimentation rate ≥3.2); ≥4 swollen joints; inadequate response to ≥1 DMARDs and/or 1–2 aTNFs receiving concomitant methotrexate (MTX; 7.5–25.0 mg/week). Pts received subcutaneous mavrilimumab 100 mg every other week (eow), based on data from the Phase IIa study,2 or golimumab 50 mg alternating with placebo eow. Key endpoints were ACR20/50/70 responses, DAS28–CRP <3.2 and <2.6, Health Assessment Questionnaire Disability Index improvement >0.22 at Week 24 and safety/tolerability. Treatment estimates for mavrilimumab and golimumab are presented with standard errors. Results Pts were randomized to mavrilimumab or golimumab (1:1) (Table). Data for pts receiving mavrilimumab 100 mg eow and golimumab 50 mg at Week 24 are shown for the aTNF-IR, DMARD-IR and overall strata (Table). The most common treatment-emergent adverse events (TEAEs) for mavrilimumab 100 mg and golimumab 50 mg were nasopharyngitis (5.7%, 1.5%), headache (4.3%, 2.9%), upper respiratory tract infection (4.3%, 2.9%), viral upper respiratory tract infection (4.3%, 2.9%), and hepatic enzyme increase (4.3%, 2.9%), respectively. Related serious TEAEs were pneumocystis pneumonia (n=1) and lung disorder (n=1) [both in golimumab-treated pts]. No deaths were reported and no significant pulmonary safety signals were identified. Conclusions In this exploratory study, mavrilimumab 100 mg eow and golimumab 50 mg demonstrated efficacy and an acceptable safety profile in DMARD-IR and aTNF-IR pts. The study was not powered to demonstrate statistical significance between mavrilimumab and golimumab. As mavrilimumab 100 mg eow has previously been shown to be suboptimal compared with 150 mg eow in DMARD-IR pts (EARTH EXPLORER 1),1 additional studies are needed to establish the benefit of a higher dose in pts with moderate to severe RA and inadequate response to aTNF agents. References Burmester G, et al. Arthritis Rheum. 2014;66:S1231 Burmester G, et al. Ann Rheum Dis. 2013;72:1445–1452 Acknowledgement Funded by MedImmune. Editorial assistance: K Alexander, QXV Comms, an Ashfield business, UK Joint senior authors: D. Close and G. Burmester Disclosure of Interest M. Weinblatt Grant/research support from: BMS, UCB, Crescendo Bioscience, Consultant for: MedImmune, Astra Zeneca, Amgen, Abbvie, BMS, Crescendo Bioscience, Lilly, Pfizer, UCB, Roche, I. McInnes Grant/research support from: Research award to University of Glasgow, Consultant for: MedImmune, Astra Zeneca, J. Kremer Shareholder of: Corrona, Grant/research support from: Abbvie, Amgen, Genentech, Lilly, Pfizer, Consultant for: Abbvie, Amgen, BMS, Genentech, Lilly, Pfizer, Employee of: Corrona, P. Miranda Grant/research support from: Clinical trials: Amgen, Medimmune, Janssen, Pfizer, Celltrion, Abbott, Sanofi, Actelion, Merck & Co, Boehringer, BMS, Consultant for: Pfizer for Etanecept (fee less than USD5000), J. Vencovský Consultant for: Pfizer, Servier, Samsumg, Eli lilley, BMS, Novartis, A. Godwood Shareholder of: AstraZeneca, Employee of: MedImmune, M. Albulescu Employee of: MedImmune, D. Close, Employee of: MedImmune, G. Burmester, Consultant for: MedImmune

Blockade of GM-CSF pathway induced sustained suppression of myeloid and T cell activities in rheumatoid arthritis

Objectives Targeting the granulocyte-macrophage colony-stimulating factor (GM-CSF) pathway holds great potential in the treatment of inflammatory diseases. Mavrilimumab, a human monoclonal GM-CSF receptor-α antibody, has demonstrated clinical efficacy in RA. Our current study aimed to elucidate mechanisms of action and identify peripheral biomarkers associated with therapeutic responses of GM-CSF antagonism in RA. Methods A 24-week placebo (PBO)-controlled trial was conducted in 305 RA patients who received mavrilimumab (30, 100 or 150 mg) or PBO once every 2 weeks. Serum biomarkers and whole blood gene expression profiles were measured by protein immunoassay and whole genome microarray. Results Mavrilimumab treatment induced significant down-regulation of type IV collagen formation marker (P4NP 7S), macrophage-derived chemokine (CCL22), IL-2 receptor α and IL-6 compared with PBO. Both early and sustained reduction of P4NP 7S was associated with clinical response to 150 mg mavrilimumab treatment. Gene expression analyses demonstrated reduced expression of transcripts enriched in macrophage and IL-22/IL-17 signalling pathways after GM-CSF blockade therapy. Myeloid and T cell-associated transcripts were suppressed in mavrilimumab-treated ACR20 responders but not non-responders. While CCL22 and IL-6 down-regulation may reflect a direct effect of GM-CSFR blockade on the production of pro-inflammatory mediators by myeloid cells, the suppression of IL-2 receptor α and IL-17/IL-22 associated transcripts suggests an indirect suppressive effect of mavrilimumab on T cell activation. Conclusion Our results demonstrated association of peripheral biomarker changes with therapeutic response to mavrilimumab in RA patients. The sustained efficacy of mavrilimumab in RA may result from both direct effects on myeloid cells and indirect effects on T cell activation after GM-CSFR blockade.

SAT0249 Safety, pharmacokinetics, pharmacodynamics and inhibition of T-cell dependent antibody response (TDAR) with MEDI4920, a novel, engineered CD40 ligand (CD40L) antagonist: results of a first-time-in-human study

Background The CD40/CD40L pathway is involved in the T-cell-dependent activation of B cells, which subsequently produce autoantibodies and inflammatory mediators that contribute to autoimmune disease pathology. MEDI4920 is an engineered fusion protein and antagonist of CD40L that lacks the fragment crystallisable (Fc) domain thought to be involved in thromboembolic events (TEs) previously reported with anti-CD40L agents containing an Fc domain. Objectives The primary objective of this Phase I, randomised, double-blind, placebo-controlled, single-ascending dose study was to evaluate the safety and tolerability of MEDI4920 in healthy subjects. Secondary objectives were to characterize T-cell-dependent antibody response (TDAR) to keyhole limpet hemocyanin (KLH) neoantigen, pharmacokinetics (PK), and anti-drug antibodies (ADAs) to MEDI4920. Methods Fifty-six healthy adult male subjects, aged 19–49 years, received a single intravenous dose of either MEDI4920 (3, 10, 30, 100, 300, 1000 or 3000 mg) or placebo. TDAR inhibition was analysed by measuring serum concentrations of IgG and IgM antibodies to KLH over time. A dose−response model was generated for TDAR inhibition. Blood samples were collected to evaluate PK, total soluble CD40L (sCD40L) and ADA concentrations. Results No deaths, TEs, severe or serious hypersensitivity reactions or infections or infusion-related reactions were observed in the study. One serious adverse event (fractured tibia) was reported in the placebo arm. MEDI4920 showed inhibition of the TDAR IgG response after the second administration of KLH on Day 15 at higher doses (≥300 mg; Figure 1A). An Emax model adequately characterised the TDAR dose−response at Day 43 (p<0.001; ED50=491 mg), with the 3000 mg dose showing 86% inhibition of the TDAR (95% CI: 68–94%; Figure 1B). MEDI4920 exhibited linear PK. MEDI4920 produced a dose-dependent increase in total sCD40L concentrations. A high ADA incidence (90%) was observed in dose cohorts ≤100 mg; however, ADA incidence (29%) and ADA titres decreased with ≥300 mg doses of MEDI4920. ADA-high subjects had reduced MEDI4920 and total sCD40L concentrations compared with ADA-negative subjects or those with low ADA titres. ADA incidence did not correlate with any clinical events. Conclusions MEDI4920 demonstrated an acceptable safety and tolerability profile, and dose-dependent inhibition of TDAR. The dose-dependent increase in total sCD40L concentrations indicates binding of MEDI4920 to sCD40L and target engagement. The decreases in ADA incidence and ADA titres correlate with increasing MEDI4920 dose, consistent with the immunosuppressive mechanism of action of this molecule. These results support further exploration of MEDI4920 administration in subjects with autoimmune diseases where the CD40/CD40L pathway is activated. Acknowledgements Funded by MedImmune. Medical writing support: D. Trivedi, MedImmune LLC, Gaithersburg, MD, USA. Technical editing support: R. Plant, QXV Comms, an Ashfield company, which was funded by MedImmune. Disclosure of Interest M. Albulescu Shareholder of: MedImmune, Employee of: MedImmune, M. Gunsior Employee of: MedImmune, J. Li Employee of: MedImmune, J. Bush Employee of: Covance Clinical Research Unit Ltd (Co. contracted [and paid] by the sponsor to conduct the study), A. Godwood Shareholder of: AstraZeneca, Employee of: MedImmune, R. Miday Employee of: MedImmune, E. Grant Shareholder of: AstraZeneca, Employee of: MedImmune, D. Howe Employee of: MedImmune, R. Faggioni Shareholder of: AstraZeneca, Employee of: MedImmune, L. Roskos Shareholder of: AstraZeneca, Employee of: AstraZeneca

AB0445 Exposure–Efficacy Analysis of Mavrilimumab in Rheumatoid Arthritis: Modeling and Simulation of Phase II Clinical Data

Background Mavrilimumab, a fully human monoclonal antibody targeting the granulocyte-macrophage colony-stimulating factor receptor (GM–CSFR) α, is in Phase IIb investigation for the treatment of rheumatoid arthritis (RA). Objectives We characterized the exposure–efficacy relationship of mavrilimumab with data from two Phase II randomized controlled trials of patients with moderate to severe RA, via population modeling and clinical simulations. Methods In a Phase IIa study, adult patients with active RA received 7 subcutaneous administrations of mavrilimumab (10, 30, 50 or 100 mg every other week [eow]). Mavrilimumab pharmacokinetics and efficacy (DAS28–CRP, ACR20/50) were modeled using a population approach. Clinical simulations were performed to facilitate the design of a Phase IIb trial, in which RA patients received placebo or mavrilimumab (30, 100, or 150 mg eow) for 24 weeks. We developed a joint probability model to describe the risk of voluntary dropouts at each scheduled visit of the Phase IIb study. The exposure–response relationship for mavrilimumab was characterized by clinical simulations via the PK-efficacy dropout model. Results Mavrilimumab and placebo treatment effects observed in the Phase IIa study were adequately described by mechanistic PK-efficacy model. Although mavrilimumab 150 mg eow was not evaluated in the Phase IIa study, improved efficacy was observed at this dosage in Phase IIb, as predicted by a priori clinical simulations. The hazard rate of patient dropout prior to next scheduled visits was significantly greater for non-responders, and substantially greater for lower dosage groups at Week 12, when patient rollover to an open-label extension study was permitted. Clinical simulations indicated that the maximum efficacy was reached at the 150-mg eow dosage. Conclusions Efficacy outcomes of the Phase IIb study confirmed the rational selection of mavrilimumab 150 mg eow as the best dosage, through modeling of Phase IIa data. Joint modeling of placebo effect, treatment response, and informative dropout greatly facilitates interpretation of Phase IIb results, and will assist in the design of late-stage clinical trials for mavrilimumab. Disclosure of Interest D. Jin Shareholder of: AstraZeneca, Employee of: MedImmune, C.-Y. Wu Shareholder of: AstraZeneca, Employee of: MedImmune, L. Roskos Shareholder of: AstraZeneca, Employee of: MedImmune, A. Godwood Shareholder of: AstraZeneca, Employee of: MedImmune, D. Close Shareholder of: AstraZeneca, Employee of: MedImmune, B. Wang Shareholder of: AstraZeneca, Employee of: MedImmune