Functional similarity of ABP 959 and eculizumab in simulated serum models of aHUS and NMOSD.

ABP 959 is being developed as a biosimilar to Soliris® (eculizumab) reference product (RP), which was approved under orphan designation for a group of rare diseases including paroxysmal nocturnal hemoglobinuria (PNH), atypical hemolytic uremic syndrome (aHUS), generalized myasthenia gravis (gMG), and neuromyelitis optica spectrum disorder (NMOSD). Development of biosimilars for therapeutics approved for rare disease indications must provide scientific rationale based on the totality of evidence (TOE). To support the TOE and the scientific justification for extrapolation to all approved indications for eculizumab RP, including but not limited to aHUS and NMOSD, we utilized simulated ex-vivo pharmacodynamic (PD) assessments to compare the complement component 5 (C5) inhibitory activity of ABP 959 and the RP. Hemolysis activity of CH50 and AH50, and Wieslab CP, AP, and LP endpoints represent the three complement activation pathways (classical, alternative, and lectin), all of which share the terminal pathway and require C5 for activity. These endpoints were evaluated in normal serum, simulated aHUS serum, and simulated NMOSD serum to provide a robust comparison. The results support the conclusion that ABP 959 and eculizumab RP exhibit highly similar inhibition of C5 function regardless of the type of serum used. This work presents a full comparison of the effect of C5 inhibition across five complement functional assays. Using this approach to confirm functional similarity of ABP 959 with eculizumab RP contributes to the TOE for biosimilarity and provides support for extrapolation based on inhibition of C5 function to other rare disease indications approved for eculizumab RP.

ORAI1 and ORAI2 modulate murine neutrophil calcium signaling, cellular activation, and host defense.

Calcium signals are initiated in immune cells by the process of store-operated calcium entry (SOCE), where receptor activation triggers transient calcium release from the endoplasmic reticulum, followed by opening of plasma-membrane calcium-release activated calcium (CRAC) channels. ORAI1, ORAI2, and ORAI3 are known to comprise the CRAC channel; however, the contributions of individual isoforms to neutrophil function are not well understood. Here, we show that loss of ORAI1 partially decreases calcium influx, while loss of both ORAI1 and ORAI2 completely abolishes SOCE. In other immune-cell types, loss of ORAI2 enhances SOCE. In contrast, we find that ORAI2-deficient neutrophils display decreased calcium influx, which is correlated with measurable differences in the regulation of neutrophil membrane potential via KCa3.1. Decreased SOCE in ORAI1-, ORAI2-, and ORAI1/2-deficient neutrophils impairs multiple neutrophil functions, including phagocytosis, degranulation, leukotriene, and reactive oxygen species (ROS) production, rendering ORAI1/2-deficient mice highly susceptible to staphylococcal infection. This study demonstrates that ORAI1 and ORAI2 are the primary components of the neutrophil CRAC channel and identifies subpopulations of neutrophils where cell-membrane potential functions as a rheostat to modulate the SOCE response. These findings have implications for mechanisms that modulate neutrophil function during infection, acute and chronic inflammatory conditions, and cancer.

Non-clinical similarity of biosimilar ABP 798 with rituximab reference product.

ABP 798 is a biosimilar to Rituxan® (rituximab reference product [RP]). Non-clinical assessments relevant to the primary and secondary mechanisms of action (MOA) contribute to the totality of the evidence (TOE) in supporting biosimilarity and are critical in providing scientific evidence for extrapolation of indications. Similarity of ABP 798 with rituximab RP was investigated across a range of biological activities which have potential impact on pharmacokinetics and clinical efficacy with non-clinical assessments relevant to MOA such as CD20 internalization, trogocytosis, binding to primary human natural killer (NK) cells as well as the ability to induce antibody-dependent cellular phagocytosis (ADCP) in peripheral blood mononuclear cells. Additionally, in vitro synergy of ABP 798 or RP with chemotherapeutic agents, in vivo xenograft studies in mice, and toxicological assessments in cynomolgus monkeys (including B cell depletion and toxicokinetics) were also conducted. Results from these non-clinical assessments contribute to the TOE supporting the biosimilarity between ABP 798 and rituximab RP across a range of primary and secondary MOAs and support justification for extrapolation to all indications of use for ABP 798 for which the RP is approved.

Binding affinity determination of therapeutic antibodies to membrane protein targets: Kinetic Exclusion Assay using cellular membranes for anti-CD20 antibody.

Antibody-based therapeutics targeting membrane proteins have evolved as a major modality for the treatment of cancer, inflammation and autoimmune diseases. There are numerous challenges, ranging from desired epitope expression to reliable binding/functional assays which are associated with developing antibodies for this target class. Specifically, having a robust methodology for characterizing antibody interaction with a membrane protein target is essential for providing guidance on dosing, potency and thus expected efficacy. Fluorescence-activated cell sorting (FACS) has been commonly used to characterize antibodies binding to membrane protein targets. FACS provides information about the antibody-receptor complex (antibody bound to cells) and the apparent equilibrium dissociation constant (KD') is elucidated by fitting the antibody-receptor binding isotherm as a function of total antibody concentration to a nonlinear regression model. Conversely, Kinetic Exclusion Assay (KinExA) has been used to measure solution-based equilibrium dissociation constant (KD) of antibodies. Here, KD is determined by measuring the free antibody concentration at equilibrium in a series of solutions in which the antibody is at constant concentration and the receptor (either in the membrane or the cell) is titrated. We measured the binding affinity of the anti-CD20 antibody, Rituximab, using both FACS and KinExA. There was ~25-fold difference in the binding affinity measured by these two techniques. We have explored this discrepancy through additional experiments around the mathematical framework involved in the analysis of these two different binding assays. Finally, our study concluded that KinExA enables accurate measurement of the KD for strong protein-protein interactions (sub-nanomolar values) compared to FACS.

Analytical and Functional Similarity Assessment of ABP 710, a Biosimilar to Infliximab Reference Product.

PURPOSE: ABP 710 has been developed as a biosimilar to infliximab reference product (RP). The objective of this study was to assess analytical similarity (structural and functional) between ABP 710 and infliximab RP licensed by the United States Food and Drug Administration (infliximab [US]) and the European Union (infliximab [EU]), using sensitive, state-of-the-art analytical methods capable of detecting minor differences in product quality attributes. METHODS: Comprehensive analytical characterization utilizing orthogonal techniques was performed with 14 to 28 unique lots of ABP 710 or infliximab RP, depending on the assay. Comparisons were used to investigate the primary structure related to amino acid sequence; post-translational modifications (PTMs) including glycans; higher order structure; particles and aggregates; primary biological properties mediated by target and receptor binding; product-related substances and impurities; and general properties. RESULTS: ABP 710 had the same amino acid sequence, primary structure, higher order structure, PTM profiles and biological activities as infliximab RP. The finished drug product had the same strength (protein content and concentration) as infliximab RP. CONCLUSIONS: Based on the comprehensive analytical similarity assessment, ABP 710 was found to be highly analytically similar to infliximab RP for all biological activities relevant for clinical efficacy and safety.

Functional and Nonclinical Similarity of ABP 980, a Biosimilar of Trastuzumab.

PURPOSE: The in vitro and in vivo pharmacologic assessment of ABP 980 similarity to its reference product is intended to compare the activity of ABP 980 and trastuzumab and support the overall conclusion of similarity based on a comprehensive analytical and functional evaluation. METHODS: This work complements the primary assessment of functional similarity with additional in vitro assays, binding studies, and non-clinical studies including human epidermal growth factor receptor-2 (HER2) kinetic binding, HER2 signaling, HER2 internalization, synergy with docetaxel chemotherapy, FcγR kinetic binding, primary natural killer and monocyte cell binding, antibody-dependent cellular phagocytosis activity, in vivo xenograft studies, and toxicokinetic parameters. RESULTS: The results contribute to the totality of evidence with respect to functional similarity and support that ABP 980 is similar to trastuzumab in all primary and secondary mechanisms of action. CONCLUSIONS: These results also support the scientific justification of extrapolation to all approved indications of trastuzumab given the established functional similarity of the two products and the same mechanisms of action across all conditions of use.

Selective ORAI1 Inhibition Ameliorates Autoimmune Central Nervous System Inflammation by Suppressing Effector but Not Regulatory T Cell Function.

The function of CD4(+) T cells is dependent on Ca(2+) influx through Ca(2+) release-activated Ca(2+) (CRAC) channels formed by ORAI proteins. To investigate the role of ORAI1 in proinflammatory Th1 and Th17 cells and autoimmune diseases, we genetically and pharmacologically modulated ORAI1 function. Immunization of mice lacking Orai1 in T cells with MOG peptide resulted in attenuated severity of experimental autoimmune encephalomyelitis (EAE). The numbers of T cells and innate immune cells in the CNS of ORAI1-deficient animals were strongly reduced along with almost completely abolished production of IL-17A, IFN-γ, and GM-CSF despite only partially reduced Ca(2+) influx. In Th1 and Th17 cells differentiated in vitro, ORAI1 was required for cytokine production but not the expression of Th1- and Th17-specific transcription factors T-bet and RORγt. The differentiation and function of induced regulatory T cells, by contrast, was independent of ORAI1. Importantly, induced genetic deletion of Orai1 in adoptively transferred, MOG-specific T cells was able to halt EAE progression after disease onset. Likewise, treatment of wild-type mice with a selective CRAC channel inhibitor after EAE onset ameliorated disease. Genetic deletion of Orai1 and pharmacological ORAI1 inhibition reduced the leukocyte numbers in the CNS and attenuated Th1/Th17 cell-mediated cytokine production. In human CD4(+) T cells, CRAC channel inhibition reduced the expression of IL-17A, IFN-γ, and other cytokines in a dose-dependent manner. Taken together, these findings support the conclusion that Th1 and Th17 cell function is particularly dependent on CRAC channels, which could be exploited as a therapeutic approach to T cell-mediated autoimmune diseases.

Orai1 enhances muscle endurance by promoting fatigue-resistant type I fiber content but not through acute store-operated Ca2+ entry.

Orai1 is a transmembrane protein that forms homomeric, calcium-selective channels activated by stromal interaction molecule 1 (STIM1) after depletion of intracellular calcium stores. In adult skeletal muscle, depletion of sarcoplasmic reticulum calcium activates STIM1/Orai1-dependent store-operated calcium entry. Here, we used constitutive and inducible muscle-specific Orai1-knockout (KO) mice to determine the acute and long-term developmental effects of Orai1 ablation on muscle structure and function. Skeletal muscles from constitutive, muscle-specific Orai-KO mice exhibited normal postnatal growth and fiber type differentiation. However, a significant reduction in fiber cross-sectional area occurred by 3 mo of age, with the most profound reduction observed in oxidative, fatigue-resistant fiber types. Soleus muscles of constitutive Orai-KO mice exhibited a reduction in unique type I fibers, concomitant with an increase in hybrid fibers expressing both type I and type IIA myosins. Additionally, ex vivo force measurements showed reduced maximal specific force and in vivo exercise assays revealed reduced endurance in constitutive muscle-specific Orai-KO mice. Using tamoxifen-inducible, muscle-specific Orai-KO mice, these functional deficits were found to be the result of the delayed fiber changes resulting from an early developmental loss of Orai1 and not the result of an acute loss of Orai1-dependent store-operated calcium entry.-Carrell, E. M., Coppola, A. R., McBride, H. J., Dirksen, R. T. Orai1 enhances muscle endurance by promoting fatigue-resistant type I fiber content but not through acute store-operated Ca2+ entry.

Store-operated CRAC channels regulate gene expression and proliferation in neural progenitor cells.

Calcium signals regulate many critical processes during vertebrate brain development including neurogenesis, neurotransmitter specification, and axonal outgrowth. However, the identity of the ion channels mediating Ca(2+) signaling in the developing nervous system is not well defined. Here, we report that embryonic and adult mouse neural stem/progenitor cells (NSCs/NPCs) exhibit store-operated Ca(2+) entry (SOCE) mediated by Ca(2+) release-activated Ca(2+) (CRAC) channels. SOCE in NPCs was blocked by the CRAC channel inhibitors La(3+), BTP2, and 2-APB and Western blots revealed the presence of the canonical CRAC channel proteins STIM1 and Orai1. Knock down of STIM1 or Orai1 significantly diminished SOCE in NPCs, and SOCE was lost in NPCs from transgenic mice lacking Orai1 or STIM1 and in knock-in mice expressing the loss-of-function Orai1 mutant, R93W. Therefore, STIM1 and Orai1 make essential contributions to SOCE in NPCs. SOCE in NPCs was activated by epidermal growth factor and acetylcholine, the latter occurring through muscarinic receptors. Activation of SOCE stimulated gene transcription through calcineurin/NFAT (nuclear factor of activated T cells) signaling through a mechanism consistent with local Ca(2+) signaling by Ca(2+) microdomains near CRAC channels. Importantly, suppression or deletion of STIM1 and Orai1 expression significantly attenuated proliferation of embryonic and adult NPCs cultured as neurospheres and, in vivo, in the subventricular zone of adult mice. These findings show that CRAC channels serve as a major route of Ca(2+) entry in NPCs and regulate key effector functions including gene expression and proliferation, indicating that CRAC channels are important regulators of mammalian neurogenesis.

Generation and characterization of fully human monoclonal antibodies against human Orai1 for autoimmune disease.

Calcium entry into T cells following antigen stimulation is crucial for nuclear factor of activated T cells (NFAT)-mediated T cell activation. The movement of calcium is mediated by calcium release-activated calcium (CRAC) channels. There are two key components of this channel: Orai1 is the pore-forming subunit located in the plasma membrane, and stromal interaction molecule 1 (STIM1) functions as a Ca(2+) sensor in the endoplasmic reticulum. A subset of human patients carry mutations in either STIM1 or Orai1 that affect protein function or expression, resulting in defective store-operated Ca(2+) influx and CRAC channel function, and impaired T cell activation. These patients suffer from a hereditary form of severe combined immune deficiency syndrome, highlighting the importance of the CRAC channel for T lymphocyte function in humans. Since autoreactive T cells play an important role in the development of autoimmune diseases such as rheumatoid arthritis, multiple sclerosis, and organ transplantation, Orai1 becomes an attractive therapeutic target for ameliorating autoimmune disease. We developed a novel approach to inhibiting CRAC function by generating high-affinity fully human monoclonal antibodies to human Orai1. These antibodies inhibited ICRAC current, store-operated Ca(2+) influx, NFAT transcription, and cytokine release. These fully human antibodies to human Orai1 may represent a novel therapeutic approach for the treatment of autoimmunity.

Part 2: Structure-activity relationship (SAR) investigations of fused pyrazoles as potent, selective and orally available inhibitors of p38alpha mitogen-activated protein kinase.

A novel class of pyrazolopyridazine p38alpha mitogen-activated protein kinase (MAPK) inhibitors is disclosed. A structure activity relationship (SAR) investigation was conducted driven by the ability of these compounds to inhibit the p38alpha enzyme, the secretion of TNFalpha in a LPS-challenged THP1 cell line and TNFalpha-induced production of IL-8 in the presence of 50% human whole blood (hWB). This study resulted in the discovery of several inhibitors with IC(50) values in the single-digit nanomolar range in hWB. Further investigation of the pharmacokinetic profiles of these lead compounds led to the identification of three potent and orally bioavailable p38alpha inhibitors 2h, 2m, and 13h. Inhibitor 2m was found to be highly selective for p38alpha/beta over a panel of 402 other kinases in Ambit screening, and was highly efficacious in vivo in the inhibition of TNFalpha production in LPS-stimulated Lewis rats with an ED(50) of ca. 0.08mg/kg.

Assessing Analytical and Functional Similarity of Proposed Amgen Biosimilar ABP 980 to Trastuzumab.

BACKGROUND: ABP 980 has been developed as a biosimilar to Herceptin® (trastuzumab). Comprehensive analytical characterization incorporating orthogonal analytical techniques was used to compare ABP 980 to trastuzumab reference products sourced from the United States (US) and the European Union (EU). METHODS: Physicochemical property comparisons included the following: primary structure related to amino acid sequence and post-translational modifications, including glycans; higher-order structure; product-related substances and impurities, including size and charge variants; subvisible and submicron particles, and protein content. In addition, functional similarity was assessed for Fab-mediated, Fc-mediated, and combined Fab- and Fc-mediated activities. RESULTS: ABP 980 has the same amino acid sequence as and similar post-translational modification profiles to trastuzumab (US) and trastuzumab (EU). Importantly, ABP 980 was found to be highly similar to trastuzumab for all functional activities related to the mechanism(s) of action. Higher-order structure, product-related substances and impurities, particles and aggregates were also highly similar between ABP 980 and trastuzumab. Where minor differences were noted, they were evaluated and found unlikely to impact clinical performance. The totality of evidence, including the pharmacokinetic clinical similarity of ABP 980, further supports that ABP 980 is highly similar to trastuzumab. CONCLUSION: Based on the comprehensive analytical similarity assessment, ABP 980 is analytically highly similar to the reference product, trastuzumab.

Cryo-EM Structure of HER2-trastuzumab-pertuzumab complex.

Trastuzumab and pertuzumab are monoclonal antibodies that bind to distinct subdomains of the extracellular domain of human epidermal growth factor receptor 2 (HER2). Adding these monoclonal antibodies to the treatment regimen of HER2-positive breast cancer has changed the paradigm for treatment in that form of cancer. Synergistic activity has been observed with the combination of these two antibodies leading to hypotheses regarding the mechanism(s) and to the development of bispecific antibodies to maximize the clinical effect further. Although the individual crystal structures of HER2-trastuzumab and HER2-pertuzumab revealed the distinct binding sites and provided the structural basis for their anti-tumor activities, detailed structural information on the HER2-trastuzumab-pertuzumab complex has been elusive. Here we present the cryo-EM structure of HER2-trastuzumab-pertuzumab at 4.36 Å resolution. Comparison with the binary complexes reveals no cooperative interaction between trastuzumab and pertuzumab, and provides key insights into the design of novel, high-avidity bispecific molecules with potentially greater clinical efficacy.

Correction: Cryo-EM Structure of HER2-trastuzumab-pertuzumab complex.

[This corrects the article DOI: 10.1371/journal.pone.0216095.].

Totality of evidence in the development of ABP 215, an approved bevacizumab biosimilar.

ABP 215 (MVASI™) is the first approved biosimilar to Avastin® (bevacizumab). It is approved in the USA and the European Union (EU) for all bevacizumab indications in these jurisdictions except for ovarian cancer in the USA due to orphan drug exclusivity. ABP 215 was shown to be structurally, functionally and clinically (pharmacokinetic, efficacy and safety) similar to the bevacizumab reference product; the pharmacokinetic study was conducted in healthy adult men (n = 202); safety and efficacy were evaluated in patients with advanced nonsquamous non-small-cell lung cancer (n = 642). Together, these results comprise the totality of evidence that provides scientific justification for extrapolation to all approved indications of the reference product and supports the clinical value of ABP 215 as an additional treatment option.

A Review of the Totality of Evidence Supporting the Development of the First Adalimumab Biosimilar ABP 501.

ABP 501 [United States: AMJEVITA™ (adalimumab-atto); European Union: AMGEVITA® (adalimumab)] is the first approved biosimilar to adalimumab [reference product (RP)], a monoclonal antibody (mAb) targeting tumor necrosis factor-alfa (TNF-α). ABP 501 has received approval for use in indications that adalimumab RP is approved for, except those protected by regulatory exclusivity. A systematic step-wise totality of evidence (TOE) approach formed the basis of approval of ABP 501; this involved methodical accumulation of scientifically robust comparative data supporting similarity in analytical, preclinical, and clinical [pharmacokinetics (PK)], efficacy, safety and immunogenicity) evaluations. As a foundational first step, comprehensive analytical assessments demonstrated that ABP 501 is structurally and functionally similar to adalimumab RP in critical quality attributes. Preclinical assessments confirmed similar activity in assessing mechanisms of action and toxicology. Clinical evaluation included a phase 1 PK equivalence study in healthy subjects and two comparative phase 3 studies that evaluated ABP 501 and adalimumab RP in two sensitive patient populations, plaque psoriasis (PsO) and rheumatoid arthritis (RA). The PK profiles of ABP 501 and adalimumab RP were similar in healthy subjects as well as patients with PsO and RA. The pivotal phase 3 study in patients with PsO demonstrated that ABP 501 was clinically similar to adalimumab RP in terms of efficacy, safety and immunogenicity in both the primary and transition phases. The pivotal phase 3 study in patients with RA also established clinical similarity between ABP 501 and adalimumab RP; an open-label extension of this study demonstrated sustained efficacy over an additional 72 weeks, with no new safety or immunogenicity concerns with ABP 501 treatment. Overall, the TOE supported the conclusion that ABP 501 is highly similar to adalimumab RP and provided scientific justification for extrapolation to all the approved indications of adalimumab RP not protected by exclusivities.Funding: Amgen Inc.

Impact of Precipitation of Antibody Therapeutics After Subcutaneous Injection on Pharmacokinetics and Immunogenicity.

Antibody therapeutics with poor solubility in the subcutaneous matrix may carry unintended risks when administered to patients. The objective of this work was to estimate the risk of antibodies that precipitate in vitro at neutral pH by determining the impact of poor solubility on distribution of the drug from the injection site as well as immunogenicity in vivo. Using fluorescence imaging in a mouse model, we show that one such precipitation-prone antibody is retained at the injection site in the subcutaneous space longer than a control antibody. In addition, we demonstrate that retention at the injection site through aggregation is concentration-dependent and leads to macrophage association and germinal center localization. Although there was delayed disposition of the aggregated antibody to draining lymph nodes, no overall impact on the immune response in lymph nodes, systemic exposure of the antibody, or enhancement of the anti-drug antibody response was evident. Unexpectedly, retention of the precipitated antibody in the subcutaneous space delayed the onset of the immune response and led to an immune suppressive response. Thus, we conclude that precipitation due to poor solubility of high doses of antibody formulations delivered subcutaneously may not be of special concern in terms of exposure or immunogenicity.

Analytical and functional similarity of Amgen biosimilar ABP 215 to bevacizumab.

ABP 215 is a biosimilar product to bevacizumab. Bevacizumab acts by binding to vascular endothelial growth factor A, inhibiting endothelial cell proliferation and new blood vessel formation, thereby leading to tumor vasculature normalization. The ABP 215 analytical similarity assessment was designed to assess the structural and functional similarity of ABP 215 and bevacizumab sourced from both the United States (US) and the European Union (EU). Similarity assessment was also made between the US- and EU-sourced bevacizumab to assess the similarity between the two products. The physicochemical properties and structural similarity of ABP 215 and bevacizumab were characterized using sensitive state-of-the-art analytical techniques capable of detecting small differences in product attributes. ABP 215 has the same amino acid sequence and exhibits similar post-translational modification profiles compared to bevacizumab. The functional similarity assessment employed orthogonal assays designed to interrogate all expected biological activities, including those known to affect the mechanisms of action for ABP 215 and bevacizumab. More than 20 batches of bevacizumab (US) and bevacizumab (EU), and 13 batches of ABP 215 representing unique drug substance lots were assessed for similarity. The large dataset allows meaningful comparisons and garners confidence in the overall conclusion for the analytical similarity assessment of ABP 215 to both US- and EU-sourced bevacizumab. The structural and purity attributes, and biological properties of ABP 215 are demonstrated to be highly similar to those of bevacizumab.

Novel protein therapeutic joint retention strategy based on collagen-binding Avimers.

Designing drugs to treat diseases associated with articular joints, particularly those targeting chondrocytes, is challenging due to unique local environmental constraints including the avascular nature of cartilage, the absence of a closed joint compartment, and a highly cross-linked extracellular matrix. In an effort to address these challenges, we developed a novel strategy to prolong residence time of intra-articularly administered protein therapeutics. Avimer domains are naturally found in membrane polypeptides and mediate diverse protein-protein interactions. Screening of a phage Avimer domain library led to identification of several low affinity type II collagen-binding Avimers. Following several rounds of mutagenesis and reselection, these initial hits were transformed to high affinity, selective type II collagen-binding Avimers. One such Avimer (M26) persisted in rat knees for at least 1 month following intra-articular administration. Fusion of this Avimer to a candidate therapeutic payload, IL-1Ra, yielded a protein construct which simultaneously bound to type II collagen and to IL-1 receptor. In vitro, IL-1Ra_M26 bound selectively to cartilage explants and remained associated even after extensive washing. Binding appeared to occur preferentially to pericellular regions surrounding chondrocytes. An acute intra-articular IL-1-induced IL-6 challenge rat model was employed to assess in vivo pharmacodynamics. Whereas both IL-1Ra_M26 and native IL-1Ra inhibited IL-6 output when co-administered with the IL-1 challenge, only IL-1Ra_M26 inhibited when administered 1 week prior to IL-1 challenge. Collagen-binding Avimers thus represent a promising strategy for enhancing cartilage residence time of protein therapeutics. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1238-1247, 2018.