Neutralizing Anti-drug Antibodies Research Articles

128 Increased dosage of elapegademase-lvlr improved metabolic and immunologic function in a patient with late-onset adenosine deaminase deficiency and neutralizing anti-drug antibodies

128 Increased dosage of elapegademase-lvlr improved metabolic and immunologic function in a patient with late-onset adenosine deaminase deficiency and neutralizing anti-drug antibodies

Analysis of systemic immune changes in patients with advanced cancer treated with immunotoxin LMB-100 and tofacitinib.

e15017 Background: LMB-100 recombinant immunotoxin delivers a modified Pseudomonas exotoxin A payload to mesothelin-expressing tumors. Almost all patients receiving LMB-100 develop anti-drug antibodies (ADAs) after 2 cycles/ 6 doses of the drug, therefore reducing peak serum drug concentrations to near the lower limit of detection. Tofacitinib is an oral JAK inhibitor that had been shown to prevent ADA formation in pre-clinical studies. Apart from assessing safety and tolerability, this trial sought to determine whether co-administration of tofacitinib with LMB-100 delays the formation of neutralizing ADAs so more patients could achieve the peak LMB-100 concentration of > 600 ng/mL during treatment cycle 2. Correlative data examining circulating immune cell subsets and cytokines pre- and on-treatment are presented here. Methods: Patients with pancreatic adenocarcinoma (n = 13) and other mesothelin-expressing solid tumors (n = 3; cholangiocarcinoma, appendix, cystadenocarcinoma) were treated for up to 3 cycles (21 days) with LMB-100 given on days 4, 6, and 8 at 2 dose levels (100 and 140 mcg/kg), accompanied by oral tofacitinib for the first 10 days of the cycle (10 mg BID). Adverse events were assessed as per CTCAE 5.0. Analysis of the cytokine data was performed using a Wilcoxon signed-rank test. Results: DLTs of grade 3 cardiac toxicity (n = 1) and grade 4 hyponatremia (n = 1) were seen at the 140mcg/kg dose of LMB-100. One patient treated at 100 mcg/kg developed a grade 4 pericardial effusion, resulting in early closure of the study for safety. The two patients who experienced cardiac toxicity had lower baseline CD4+ cells and increased CD19+ cells post-LMB-100 treatment. Four out of 8 evaluable patients achieved LMB-100 concentration above the threshold during cycle 2, and 2 out of 3 did so during cycle 3. Analysis of peripheral blood cytokine levels showed sustained increases in TNF-α, IL-8, and IL-10 following LMB-100 administration through to the start of cycle 2. Percentage of Tregs increased through cycle 1 in patients who developed drug-neutralizing ADAs and was significantly higher than in patients with LMB-100 levels above threshold at the start of cycle 2. Conclusions: Combination of LMB-100 with tofacitinib is not safe. An insufficient number of patients was treated to conclusively assess the ability of tofacitinib to stop or delay ADA formation. Increases in circulating Tregs were observed in patients with early neutralizing ADA formation. Clinical trial information: NCT04034238 .

A machine learning approach for identifying variables associated with risk of developing neutralizing antidrug antibodies to factor VIII

A key unmet need in the management of hemophilia A (HA) is the lack of clinically validated markers that are associated with the development of neutralizing antibodies to Factor VIII (FVIII) (commonly referred to as inhibitors). This study aimed to identify relevant biomarkers for FVIII inhibition using Machine Learning (ML) and Explainable AI (XAI) using the My Life Our Future (MLOF) research repository. The dataset includes biologically relevant variables such as age, race, sex, ethnicity, and the variants in the F8 gene. In addition, we previously carried out Human Leukocyte Antigen Class II (HLA-II) typing on samples obtained from the MLOF repository. Using this information, we derived other patient-specific biologically and genetically important variables. These included identifying the number of foreign FVIII derived peptides, based on the alignment of the endogenous FVIII and infused drug sequences, and the foreign-peptide HLA-II molecule binding affinity calculated using NetMHCIIpan. The data were processed and trained with multiple ML classification models to identify the top performing models. The top performing model was then chosen to apply XAI via SHAP, (SHapley Additive exPlanations) to identify the variables critical for the prediction of FVIII inhibitor development in a hemophilia A patient. Using XAI we provide a robust and ranked identification of variables that could be predictive for developing inhibitors to FVIII drugs in hemophilia A patients. These variables could be validated as biomarkers and used in making clinical decisions and during drug development. The top five variables for predicting inhibitor development based on SHAP values are: (i) the baseline activity of the FVIII protein, (ii) mean affinity of all foreign peptides for HLA DRB 3, 4, & 5 alleles, (iii) mean affinity of all foreign peptides for HLA DRB1 alleles), (iv) the minimum affinity among all foreign peptides for HLA DRB1 alleles, and (v) F8 mutation type.

Artificial Intelligence (AI) based approach for identifying biomarkers associated with neutralizing antidrug antibodies to Factor VIII used in Hemophilia A treatment

Abstract Lack of clinically validated markers associated with the development of neutralizing antibodies (inhibitors) to the replacement protein-drug, Factor VIII (FVIII) is a major challenge in managing Hemophilia A (HA). By utilizing Machine Learning (ML) and Explainable AI (XAI) we identified and ranked relevant variables (biomarkers) that could be predictive for developing inhibitors to FVIII drugs in hemophilia A patients. The dataset used for the study was derived from the My Life Our Future (MLOF) repository and included variables such as age, race, ethnicity, mutations in the F8 gene and the Human Leucocyte Antigen Class II (HLA-II) type. We computed the number of foreign FVIII derived peptides, based on the alignment of the endogenous FVIII and infused drug sequences, and the foreign-peptide HLA-II molecule binding affinity (using the NetMHCIIpan algorithm). The complete dataset with the added variables was trained and validated using multiple ML classification models to identify the top performing model, which was chosen for further processing with XAI via SHAP (SHapley Additive exPlanations) to identify the variables critical for the prediction of FVIII inhibitor development in a hemophilia A patients. The top five variables for predicting inhibitor development based on SHAP values are: (i) the baseline activity of the FVIII protein, (ii) mean affinity of all foreign peptides for HLA DRB 3, 4, & 5 alleles, (iii) mean affinity of all foreign peptides for HLA DRB1 alleles, (iv) the maximum affinity among all foreign peptides for HLA DRB1 alleles, and (v) F8 mutation type. This research was supported by funds from the Hemostasis Branch/Division of Plasma Protein 344 Therapeutics/Office of Tissues and Advanced Therapies/Center for Biologics Evaluation and Research 345 of the U.S. Food and Drug Administration and in part by an appointment to the Research Participation 346 Program at the Center for Biologics Evaluation and Research administered by the Oak Ridge Institute 347 for Science and Education through an interagency agreement between the U.S. Department of Energy 348 and the U.S. Food and Drug Administration. The MLOF program was developed as a partnership 349 between NHF, ATHN, Bloodworks Northwest, and Bioverativ and supported financially by 350 Bioverativ, NHF, Bloodworks Northwest, and ATHN.

Immunomodulator comedication promotes the reversal of anti-drug antibody-mediated loss of response to anti-TNF therapy in inflammatory bowel disease

PurposeLoss of therapeutic response (LOR) due to anti-drug antibodies (ADA) against tumor necrosis factor (TNF) inhibitors is common in patients with inflammatory bowel disease (IBD). We aimed to investigate whether immunomodulator comedication can reverse the immunogenic LOR to TNF inhibitors in IBD.MethodsIn this real-world retrospective cohort study, 123 IBD patients with neutralizing ADA to infliximab or adalimumab and concomitant subtherapeutic trough levels were screened for clinical LOR. Subsequent ADA and trough level measurements and clinical outcomes were analyzed for patients who received either immunomodulator comedication or dose intensification of infliximab or adalimumab to overcome LOR.ResultsFollowing immunogenic LOR, the initial anti-TNF regimen was optimized in 33 patients. In univariable and multivariable logistic regression analyses, immunomodulator comedication was identified as the crucial factor for regaining clinical remission and ADA clearance. Detectable trough levels (≥ 0.98 or ≥ 1.00 mg/L, respectively) had optimal predictive performance for both endpoints in receiver operating characteristics curves [area under the curve 0.86 (95% confidence interval 0.68–1.00) for regaining clinical remission, 0.87 (0.71–1.00) for ADA clearance]. Furthermore, 11/20 patients (55%) on a comedication with azathioprine or methotrexate and 2/13 patients (15%) receiving anti-TNF dose intensification exclusively (P = 0.032) exhibited ADA elimination, regain of therapeutic trough levels, and clinical remission. Regain of clinical remission alone was achieved in 17/20 (85%) patients receiving comedication and 2/13 (15%) patients receiving anti-TNF dose intensification (P = 1.6 × 10−4).ConclusionImmunogenic LOR to infliximab or adalimumab in IBD can be successfully reversed using immunomodulator comedication.

A First-in-Human Phase 1 Study of Abbv-319, an Antibody-Drug Conjugate Composed of a CD19 Antibody Linked to a Potent Proprietary Glucocorticoid Receptor Modulator, in Patients with Relapsed or Refractory B-Cell Malignancies

Background Systemic glucocorticosteroids (ie, glucocorticoid receptor modulators [GRMs]) show robust monotherapy activity against B-cell malignancies at high doses; however, they may be accompanied by steroid-associated toxicities that limit dosing. CD19 is a marker essential for B-cell proliferation and has high expression across B-cell malignancies including diffuse large B-cell lymphoma (DLBCL), follicular lymphoma (FL), and chronic lymphocytic leukemia (CLL). ABBV-319 is a CD19-GRM antibody-drug conjugate (ADC) composed of an optimized high-affinity immunoglobulin G1 antibody conjugated to a potent proprietary glucocorticosteroid payload. ABBV-319 takes advantage of both enhanced antibody-dependent cellular cytotoxicity (via afucosylation) and targeted GRM payload delivery to maximize anticancer activity while lowering the risk of systemic steroid toxicities. Preclinically, ABBV-319 demonstrates sustained antitumor efficacy in models of human B-cell malignancies that compares favorably with approved therapeutics. This phase 1 study evaluates safety and clinical activity of ABBV-319 monotherapy in patients with relapsed or refractory (R/R) B-cell malignancies. Methods This is a phase 1, first-in-human, open-label, dose-escalation, dose-expansion, biomarker/pharmacodynamic (PD) study in patients aged ≥18 years with R/R B-cell malignancies. Key eligibility criteria include measurable disease and Eastern Cooperative Oncology Group performance status of 0 or 1. In addition, patients must meet predefined criteria for adrenal, bone marrow, kidney, and liver function, coagulation parameter levels, and hemoglobin A1c levels (dose escalation only) during screening. The primary objectives are to evaluate safety, tolerability, pharmacokinetics (PK), and immunogenicity of ABBV-319 and identify a recommended phase 2 dose (RP2D). The secondary objective is to evaluate the efficacy of ABBV-319 in patients with R/R DLBCL, FL, and CLL. Exploratory objectives include evaluating the effect of ABBV-319 on QT prolongation and evaluating PD and predictive biomarkers. This study will be conducted in 2 parts - dose escalation (Part 1) and dose expansion (Part 2). Part 1 aims to determine the RP2D for ABBV-319 following a Bayesian optimal interval design, with a maximum of 2-fold increments that reduce as the dose increases. RP2D will be determined on the basis of all the data collected in Part 1 including safety, tolerability, PK, PD, and efficacy, if available. Part 2 will further evaluate ABBV-319 at the RP2D in 3 separate subtypes of B-cell malignancies - DLBCL, FL, and CLL. A total of 114 patients are planned to be enrolled - 54 patients with various R/R B-cell malignancies in Part 1, and 60 patients in Part 2 (20 patients included for each R/R B-cell malignancy subtype: DLBCL, FL, and CLL). ABBV-319 will be administered intravenously until disease progression, intolerable toxicity, or other study discontinuation criteria are met, for a maximum of ~24 months from the last patient enrolled. Safety assessments include adverse event monitoring (per National Cancer Institute Common Terminology Criteria for Adverse Events v5.0), physical examinations, vital sign measurements, and clinical laboratory testing. Dose-limiting toxicities will be assessed. PK parameters including maximum observed serum/plasma concentration (Cmax), time to Cmax, terminal plasma elimination half-life, and area under the serum/plasma concentration-time curve will be analyzed using noncompartmental methods for ABBV-319 total antibody, ADC, and unconjugated GRM payload. Antidrug antibodies (ADAs) and neutralizing ADAs may also be determined, as appropriate. Efficacy will be evaluated in terms of response per disease-specific criteria (including International Workshop on Chronic Lymphocytic Leukemia, International Workshop on Waldenstrom's Macroglobulinemia, and Lugano classification). Duration of response, time to response, progression-free survival, and overall survival will be evaluated per Kaplan-Meier analysis. QT prolongation, PD, and biomarker data will be assessed as changes from baseline and may be summarized for each scheduled postbaseline visit.

Airway autoimmunity, asthma exacerbations, and response to biologics.

Biologic therapies in asthma are indicated in severe disease, and they are directed against specific inflammatory modulators that contribute to pathogenesis and severity. Currently approved biologics target T2 cytokines (IgE, IL-5, IL-4/IL-13, and TLSP) and have demonstrated efficacy in clinical outcomes such as exacerbation rate and oral corticosteroid dose reductions, blood and airway eosinophil depletion, and lung function improvement. However, a proportion of these patients may show inadequate responses to biologics, with either initial lack of improvement or clinical and functional worsening after an optimal initial response. Exacerbations while on a biologic may be due to several reasons, including imprecise identification of the dominant effector pathway contributing to severity, additional inflammatory pathways that are not targeted by the biologic, inaccuracies of the biomarker used to guide therapy, inadequate dosing schedules, intercurrent airway infections, anti-drug neutralizing antibodies, and a novel phenomenon of autoimmune responses in the airways interfering with the effectiveness of the monoclonal antibodies. This review, illustrated using case scenarios, describes the underpinnings of airway autoimmune responses in driving exacerbations while patients are being treated with biologics, device a strategy to evaluate such exacerbations, an algorithm to switch between biologics, and perhaps to consider two biologics concurrently.

Interference in a Neutralizing Antibody Assay for Odronextamab, a CD20xCD3 Bispecific mAb, from Prior Rituximab Therapy and Possible Mitigation Strategy

A cell-based assay was developed to detect neutralizing anti-drug antibodies (NAbs) against odronextamab, a CD20xCD3 bispecific monoclonal antibody (mAb) under investigation for treatment of CD20+ B cell malignancies. In this assay, odronextamab bridges between two cell types, CD20-expressing HEK293 cells and CD3-expressing Jurkat T cells that generate a luciferase signal upon CD3 clustering. Patient samples containing NAbs directed to either arm of the bispecific drug block the odronextamab bridge formation between the cell lines thus preventing the generation of the luciferase signal. We determined that other anti-CD20 therapeutics also block bridge formation, resulting in false-positive results. In patient samples from odronextamab clinical trials, approximately 30% of baseline samples had a strong false-positive NAb signal that correlated with the presence of prior rituximab (anti-CD20) therapy. We determined that rituximab interference can be minimized by the addition of anti-rituximab antibodies in the NAb assay. Understanding and mitigating the impact of prior biologic exposure is increasingly important for implementing a successful bioanalytical strategy to support clinical drug development, especially in the immuno-oncology field.Graphical Odronextamab neutralizing antibody assay, interference, and mitigation. A Design of the odronextamab neutralizing antibody (NAb) assay where anti-CD20xCD3 drug bridges between CD20-expressing HEK293 cells and Jurkat T cells expressing an NFAT response element and luciferase reporter. True NAb prevents odronextamab from bridging between target and effector cells, thus preventing the expression of luciferase. B Interference with odronextamab from other anti-CD20 therapeutic antibodies (e.g., rituximab) from prior disease treatment generates a false-positive NAb result. Assay interference can be mitigated with an anti-idiotypic antibody against the interfering therapy.

Clinical efficacy and safety of the BAT1706 (proposed bevacizumab biosimilar) compared with reference bevacizumab in patients with advanced nonsquamous NSCLC: A randomized, double-blind, phase III study.

9041 Background: A Randomized, Double-blind, Phase III Study was conducted to confirm clinical similarity between BAT1706, a proposed biosimilar to reference bevacizumab, and EU-bevacizumab in patients with advanced non-squamous non-small cell lung cancer (NSCLC). Methods: Patients were randomized 1:1 to BAT1706 plus paclitaxel and carboplatin (Arm A) or EU-bevacizumab plus paclitaxel and carboplatin (Arm B) given three weeks for 6 cycles, followed by maintenance therapy with BAT1706 or EU- bevacizumab. The primary endpoint was overall response rate at Week 18 (ORR18). Secondary endpoints included ORR at Week 6 and 12, best ORR, duration of response (DoR), progression-free survival (PFS), and overall survival (OS). Results: A total of 651 patients were randomized: BAT1706 (n = 325) or EU- bevacizumab (n = 326). In total, 649 randomized patients (BAT1706 (n = 325) or EU- bevacizumab (n = 324)) received at least one cycle of combination treatment. The median duration of therapy was 29.1 weeks (ranging from 3.0 to 62.1 weeks) in the Arm A and 27.0 weeks (ranging from 3.0 to 53.9 weeks) in the Arm B. The extent of exposure to BAT1706 and EU- bevacizumab was similar between these two arms. Overall, the proportion of patients achieving an ORR by Week 18 was comparable across Arm A and B (48.0% and 44.5%). The ORR risk ratio of 1.08 with 90% CI (0.94, 1.24) and the ORR risk difference of 0.03, with 95% CI (-0.04, 0.11) were within pre-specified equivalence margin. In addition, the multivariate-adjusted risk ratio was 1.07, with a 90% CI (0.93, 1.22). The ORR18 risk difference between BAT1706 and EU- bevacizumab was 0.03, with the 2-sided 95% CI (-0.04, 0.11) that fell entirely within pre-specified equivalence margin. In addition, the multivariate-adjusted risk difference was 0.03, with a 95% CI (-0.04, 0.11). The hazard ratio stratified for time to PFS was 0.915 and the PFS rate at 12 months was 20.7% versus 21.8%. At the end of the study, there were no significant differences between both the treatments. The incidence of treatment-emergent adverse events (TEAEs) and study drug-related TEAEs was similar between these two arms. Overall, the safety profiles of BAT1706 were consistent with that of EU- bevacizumab, no new safety signals or noticeable trends were observed. The mean serum concentrations were comparable between BAT1706 and EU- bevacizumab over the entire sampling interval both in pre-dose and post-dose. The incidence of positive anti-drug antibodies results was low (≤5%) and decreased over time in both treatment arms. No patient was detected to have positive neutralizing anti-drug antibody result during the study. Conclusions: BAT1706 demonstrated clinical equivalence to reference EU-bevacizumab in terms of efficacy, safety, pharmacokinetics, and immunogenicity. Clinical trial information: NCT03329911.

Inclisiran: A Novel Small Interfering RNA Drug for Low-Density Lipoprotein Reduction.

Inclisiran increases the number of low-density lipoprotein surface receptors expressed on hepatocytes using small interfering RNA directed against proprotein convertase subtilisin/kexin type 9 (PCSK9) mRNA. This novel mechanism can reduce low-density lipoprotein by ≈50%, like reductions achieved with high-intensity statins or PCSK9-inhibiting monoclonal antibodies. Inclisiran is indicated in the treatment of adults with heterozygous familial hypercholesterolemia or clinical atherosclerotic cardiovascular disease, unable to achieve target LDL concentrations with diet and maximally tolerated statin therapy. It is more expensive than PCSK9-inhibiting monoclonal antibodies and still lacks clinical evidence for the expected reduction in atherosclerotic cardiovascular disease events when added to statin therapy. Although some patients experience injection-site reactions of mild or moderate severity, current evidence suggests a strong safety profile with total and serious adverse events approximating that of placebo. The dosing protocol of inclisiran offers its biggest clinical advantage over PCSK9-inhibiting monoclonal antibodies, being administered only every 6 months after initial baseline and 3-month doses rather than every second or fourth week. Unlike PCSK9-inhibiting monoclonal antibodies, inclisiran has not as yet been noted to induce neutralizing antidrug antibodies that can impact drug efficacy. Thus, inclisirin is a novel small interfering RNA molecule that provides further options in the management of hypercholesterolemia refractory to statins alone. However, cost and evidence considerations suggest it should not supplant adjunctive therapy with the PCSK9-inhibiting monoclonal antibodies, despite having an efficacy, safety, tolerability, and drug interaction profile superior to other antihypercholesterolemic options such as lomitapide, niacin, bile acid sequestrants, and bempedoic acid.

A comparative multi-tiered immunogenicity assessment of biosimilar pegylated filgrastim: validation of methods for clinical assessment of INTP5

ABSTRACT Background and Objective Validated and highly sensitive assays are required for comparative assessment of immunogenicity of biosimilars. For INTP5, a biosimilar pegylated filgrastim, the immunogenicity assessment included tiers that allowed for assessment of antibodies against the PEG and the Filgrastim moieties for comparative clinical immunogenicity assessment. Methods Electrochemiluminescence immunoassay (ECLIA) was used for Screening, Specificity, and Titer assays for detecting anti-drug antibodies (ADAs) and cell-based method for neutralizing ADAs. The methods were validated to enable use of same methods irrespective of biosimilar or reference arms. Results The ADA and cell-based assay for neutralizing antibody detection were validated with a sensitivity capable of detecting binding Anti-Pegfilgrastim antibody at ~40 ng/mL and Neutralizing antibody at ~380 ng/mL and used for a comparative immunogenicity study. Of 194 subjects, 10 subjects had confirmed positive anti-drug-antibody in the biosimilar arm and 9 in the reference arm. None of the subjects were detected with neutralizing anti-drug antibodies. Conclusion This work demonstrates the application of a rigorous approach toward validation of assays for immunogenicity studies for biosimilars. Highly sensitive, precise, and robust assays were used to conclude comparable low incidences of anti-drug antibodies in both biosimilar and innovator arms of the clinical study for Pegfilgrastim.

Vedolizumab Immunogenicity With Long-Term or Interrupted Treatment of Patients With Inflammatory Bowel Disease.

Patients in the GEMINI 1 or 2 study (NCT00790933; Eudra CT2008‐002784‐14) with ulcerative colitis or Crohn disease had low immunogenicity rates after vedolizumab treatment for up to 52 weeks. We report immunogenicity rates from the GEMINI long‐term safety (LTS) study using a new drug‐tolerant electrochemiluminescence assay, including analyses in patients who received continuous vedolizumab induction and maintenance in GEMINI 1 or 2 and long term safety, or vedolizumab induction and placebo maintenance in GEMINI 1 or 2 followed by re‐treatment in long term safety (treatment interruption). Patients were enrolled in GEMINI long term safety from GEMINI 1, 2, or 3, or as de novo vedolizumab‐treated patients; all received vedolizumab 300 mg intravenously every 4 weeks. Vedolizumab antidrug antibody (ADA) status was determined by electrochemiluminescence assay; ADA‐positive samples were characterized by neutralizing activity. Vedolizumab ADA data were available for 1753 patients: 1513 continuously treated with vedolizumab before/during GEMINI long term safety, 240 re‐treated after treatment interruption. Among continuously treated patients, 36 (2.4%) were ADA positive (15 persistently, 20 neutralizing ADA positive). Among re‐treated patients, 53 (22.1%) were ADA positive (42 persistently, 40 neutralizing ADA positive). Longitudinal immunogenicity rates increased during placebo maintenance (19.4% at week 52), then decreased in GEMINI long term safety to rates (0 at the final visit) similar to continuously treated patients. ADA positivity was 1.1% vs 2.5% (continuous treatment) and 23.1% vs 22.0% (re‐treatment) among patients with and without infusion‐related reactions, respectively. Long‐term vedolizumab treatment was associated with generally low immunogenicity rates; vedolizumab–re‐treated patients had higher rates during placebo maintenance, which decreased during re‐treatment. No relationship was observed between immunogenicity and infusion‐related reactions.

Efficacy and safety of levilimab in combination with methotrexate in subjects with rheumatoid arthritis: Results of phase II AURORA study

Levilimab (LVL) is a monoclonal antibody against the interleukin-6 receptor (IL6R). The article presents data obtained during 56 weeks of the AURORA phase II study.Objective: to evaluate the efficacy safety and immunogenicity of LVL in methotrexate (MTX) resistant patients with active rheumatoid arthritis (RA).Materials and methods. 105 patients with active RA were randomized in a 1:1:1 ratio into two LVL or placebo groups. LVL was administered subcutaneously at a dose of 162 mg every week (QW) or every other week (Q2W). All patients received MTX. After evaluating the primary endpoint of 20% improvement in ACR criteria (ACR20) at week 12, patients in the placebo group were switched to LVL Q2W. The study duration was 56 weeks. The frequency, profile, degree and severity of adverse events were determined in each group for safety assessment. The immunogenicity of LVL was determined by the proportion of patients with identified binding and neutralizing antidrug antibodies. Results. LVL in both regimens was superior to placebo. At week 12, the incidence of ACR20 achievement was 77.1% (LVL QW), 57.1% (LVL Q2W), and 17.1% (placebo) with 95% confidence intervals [37.53; 82.54] (p<0.0001) and [19.08; 68.42] (p=0.003) for the effect difference between LVL and placebo groups. The clinical response, more pronounced in the LVL QW group, persisted until week 52 with an increase in the proportion of patients with ACR50/70, low activity and RA remission. The most common treatment-related adverse events were laboratory abnormalities (predominantly grade 1–2) such as neutropenia, elevated alanine aminotransferase, aspartate aminotransferase levels, hypercholesterolemia, and elevated triglyceride levels. Antidrug antibodies were not identified.Conclusion. In MTX-resistant patients with active RA, the efficacy of both LVL regimens at a dose of 162 mg in combination with MTX was significantly superior to MT monotherapy. LVL QW lead to highest treatment response. LVL has been shown to be well tolerated and low immunogenicity. LVL safety profile is similar to IL6R inhibitors.

Refractoriness to drugs in migraine may be the result of developing anti-drug antibodies

IntroductionMigraine is a common neurological disease and is listed second among the most disabling health conditions worldwide. Refractory migraine (RM) is a term used to emphasize the unresponsiveness of migraine to various treatment options, encompassing both episodic refractory and chronic refractory migraine. In this paper we discuss various known and possible mechanisms of pharmacological refractoriness in RM, such as possible involvement of the gut microbiome, the blood-brain barrier, migraine genetics and various mechanisms of pharmacokinetic and pharmacodynamic tolerance. Development of medication-overuse headache as a secondary disorder following migraine is also considered. We argue that the available literature is insufficient to fully explain the mechanisms of refractoriness and we present our hypothesis.HYPOTHESIS. Refractoriness to drugs in migraine may be the result of developing anti-drug antibodies. Most migraine drugs are small molecules, which cannot elicit an immune response on their own due to their size. However, such molecules can bind to peptide carriers in their vicinity, greatly increasing their immunogenicity. A small molecule possessing this binding ability is called a hapten. Haptens form hapten-carrier complexes (HCCs), which can evoke powerful immune responses. Immune reactions to HCCs are known to be predominantly ‘drug allergies’ or type 1 drug hypersensitivity reactions’, usually resulting from IgE or non-IgE mediated mast cell degranulation. We argue that the immune reaction to HCCs can take shape in developing neutralizing anti-drug antibodies (ADA) in the form of IgG and IgA class antibodies. Since biological therapeutics, such as various monoclonal antibodies, face the issue of ADA-induced drug tolerance, HCCs, being similar in the sense that they carry peptide antigens, are of sufficient size and may be considerably immunogenic, can be responded to in a similar way by producing neutralizing ADA. Furthermore, we argue that such responses are expected to happen more frequently than is thought, due to IgG and IgA being prevalent antibodies, which utilize their neutralizing capabilities on regular basis. Finally, it is important to consider that neutralization reactions in normal immune responses are typically asymptomatic, with the only clinical expression being progressive drug tolerance. These cases may be overshadowed by the life-threatening cases of drug allergy induced anaphylaxis, possibly leading to neutralization reactions being underrecognized. DiscussionThis hypothesis aims to stimulate more research regarding drug resistance, and if it receives support from empirical evidence, it may help further elucidate the mechanisms underlying refractory diseases and contribute to the development of more effective treatment of many disorders.

Phase 1/2 Study to Evaluate the Pharmacokinetics, Pharmacodynamics, Safety, and Efficacy of Marzeptacog Alfa (activated) in the Treatment of Episodic Bleeding in Subjects with Inherited Bleeding Disorders

Background There are many inherited conditions that present with episodic bleeding effectively treated with Factor VIIa (FVIIa). These include Factor VII deficiency (FVIID), an autosomal recessive disorder caused by ineffective or reduced levels of FVII, Glanzmann thrombasthenia (GT), a rare platelet disorder associated with a deficiency or dysfunction of glycoprotein IIb/IIIa, Hemophilia A with inhibitors (HawI), an X-linked, recessive, bleeding disorder caused by a deficiency of FVIII with development of inhibitors against FVIII, rendering them refractory to replacement treatment. Although emicizumab prophylaxis is available for HAwI (HAwI-E), breakthrough bleeding still occurs. Treatment of episodic bleeding requires technical expertise to gain the requisite intravenous (IV) access and is often associated with pain. This causes delays in administration which results in prolonged bleeding and accumulation of blood in the joint or other bleeding sites. Currently approved FVIIa containing products take 6-24 hours to achieve hemostasis and maintain efficacy. Marzeptacog alfa (activated) (MarzAA), a novel variant activated recombinant FVII (rFVIIa), is being developed for subcutaneous (SQ) administration to address this important unmet need. Data from the Phase 1 study, MAA-102, demonstrated that SQ MarzAA is quickly absorbed and has the potential to achieve and maintain plasma levels in the desired range with an acceptable safety profile. This open-label, multi-center, Phase 1/2 study is designed to evaluate the pharmacokinetics, pharmacodynamics, safety and efficacy of MarzAA for on-demand treatment of spontaneous or traumatic bleeds in adolescents and adults with FVIID (cohort 1), GT (cohort 2) and HAwI-E (cohort 3). It is estimated that 24 subjects will be enrolled across all 3 cohorts at approximately 25 sites in 5 countries. Study Design and Methods Key inclusion criteria:Eligible male or female subjects, ≥ 12 years of age must have confirmed diagnosis of: FVIID (cohort 1), GT (cohort 2) or HAwI treated with the same dose of emicizumab for at least 4 weeks, HAwI-E (cohort 3); history of bleeding with annualized bleeding rate (ABR) of ≥ 8 for cohorts 1 and 2 and ABR of ≥ 1 for cohort 3; investigator-confirmed subject's ability to identify bleeds and administer MarzAA SQ at home. Key exclusion criteria:Subjects should not have previous exposure to SQ administration of rFVIIa or exposure to any other variant rFVIIa; known positive antibody or hypersensitivity to MarzAA , FVIIa, or variants thereof; history of other coagulation disorder(s); platelet count <50,000/uL; CD 4 T cell count <200 cells/mm3; FVIID subjects with specific genotypes. Treatment:In Phase 1, subjects will receive a single dose of IV MarzAA followed by ascending doses of SQ MarzAA for PK assessments. Once the Phase 2 dose for the cohort is confirmed, subjects will be treated for episodic bleeding with SQ MarzAA until ≥30 eligible bleeds in Cohorts 1 and 2, and ≥15 eligible bleeds in Cohort 3 have been treated with MarzAA. Endpoints:Primary endpoints by cohort: Phase 1 includes PK of ascending SC doses of MarzAA and confirmation of the Phase 2 dose; Phase 2 includes the percentage of treated bleeds resulting in effective hemostasis (excellent or good) at 24 hours after the initial dose. Key secondary endpoints by cohort: Phase 1 includes PK and PD of IV and SQ MarzAA and PK dose proportionality; Phase 2 includes time to cessation of bleeding after the initial dose; percentage of treated bleeds resulting in effective hemostasis at fixed timepoints; percentage of bleeds that maintain hemostasis at 48 hours after the initial dose and use and amount of rescue therapy. Key safety endpoints for the study include the incidence of adverse events; occurrence of thrombotic events and binding and/or neutralizing anti-drug antibodies. Key exploratory endpoints for Phase 2 include assessment of patient satisfaction with the Treatment Satisfaction Questionnaire for Medicine- 9; assessment of pain using the Visual Analogue Scale; evaluation of the time required to administer treatment. Statistics:The appropriate statistics of all recorded, measured, and calculated parameters will be reported and include 95% confidence intervals, sample size, mean, standard deviation, and median. These will be reported separately for intent to treat and per protocol subjects in Phase 2. Safety results will be tabulated by cohort and in aggregate. Figure Disclosures Neuman: Catalyst Biosciences:Current Employment, Current equity holder in publicly-traded company.Desai:Catalyst Biosciences:Current Employment, Current equity holder in publicly-traded company.Del Greco:Catalyst Biosciences:Current Employment, Current equity holder in publicly-traded company.Knudsen:Catalyst Biosciences:Current Employment, Current equity holder in publicly-traded company.Levy:Catalyst Biosciences:Current Employment, Current equity holder in publicly-traded company.

A Phase 1b, Open-Label Study of Eftozanermin Alfa in Combination with Bortezomib and Dexamethasone in Patients with Relapsed or Refractory Multiple Myeloma

Background Many patients (pts) with multiple myeloma (MM) will relapse after treatment or become refractory to all therapies currently available. For these pts, the prognosis is poor and there is a clear unmet need to identify agents with novel mechanisms of action. The tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) pathway has a distinct role in the induction of apoptosis in tumor cells, and activating this pathway could represent an attractive therapeutic approach. Early generation TRAIL receptor agonists had minimal efficacy in pts with MM, which may be due to suboptimal TRAIL receptor clustering. Eftozanermin alfa (formerly ABBV-621) is a next-generation TRAIL receptor agonist specifically designed to optimize receptor clustering. The ongoing first-in-human study of eftozanermin alfa (NCT03082209) demonstrated a tolerable safety profile in pts with previously treated solid tumors and hematologic malignancies. Preclinical ex vivo and in vivo models of MM indicate combinatorial activity of eftozanermin alfa with proteasome inhibitors (PIs) resulting in enhanced efficacy. The addition of eftozanermin alfa to the well-established regimen of the PI bortezomib and dexamethasone may improve efficacy outcomes in pts with relapsed/refractory (R/R) MM. Study Design and Methods This is a phase 1b, open-label, nonrandomized, multicenter study enrolling pts (≥18 years, Eastern Cooperative Oncology Group score 0-1) with R/R MM. Approximately 40 pts are planned for enrollment. The primary objectives of the study are to determine the recommended phase 2 dose (RP2D) of eftozanermin alfa when given in combination with bortezomib and dexamethasone, and to assess the efficacy of this combination on the basis of overall response rate (ORR). Secondary objectives include assessing the safety and tolerability of eftozanermin alfa with bortezomib and dexamethasone and evaluating the rate of very good partial response (VGPR) or better, the duration of response (DOR), and pharmacokinetics (PK). Key inclusion criteria are pts with R/R MM who have received at least 3 but no more than 6 prior lines of therapy (including an immunomodulatory agent, a PI, and an anti-CD38 antibody) and have documented disease progression during or after the most recent therapy. Pts must also have measurable disease per standard International Myeloma Working Group (IMWG) criteria at baseline and adequate hematologic, hepatic, and renal function. Pts will be excluded if they have primary refractory disease, received bortezomib in the most recent prior therapy, or have peripheral neuropathy grade ≥2 or grade 1 with pain. The study consists of a screening period, a treatment period, and a follow-up period; dosing schedule details are presented in Figure. After screening, pts will receive eftozanermin alfa with bortezomib and dexamethasone until unacceptable toxicity, confirmed progressive disease, or other protocol-specified reasons for discontinuation are met. Treatment may continue for maximum 12 cycles. A safety lead-in will be performed to determine the RP2D of eftozanermin alfa when combined with bortezomib and dexamethasone. Dose escalation during the safety lead-in will be guided using a Bayesian optimal interval design with a target toxicity rate of 33%. The primary efficacy endpoint is the ORR, defined as the proportion of pts with partial response or better per IMWG criteria. Other efficacy endpoints include DOR, VGPR or better rate, and progression-free and overall survival. For all binary endpoints, the estimated proportion and associated 2-sided 90% Clopper-Pearson exact confidence intervals will be provided. The time-to-event endpoints will be summarized using the Kaplan-Meier method. Safety evaluations will include assessment of dose-limiting toxicities during cycle 1 of the safety lead-in, and monitoring of adverse events, vital signs, and clinical laboratory measures throughout the study. Samples for PK analysis, biomarker assessments, and assays for antidrug and neutralizing antidrug antibodies will be obtained at protocol-specified visits. Biomarker analyses may include evaluation of death receptor 4/5 expression, chromosomal abnormalities, and minimal residual disease status. Approximately 20 sites in 6 countries are planned to be involved in the study, which is anticipated to start in September 2020. Figure 1 Disclosures Richardson: Celgene/BMS, Oncopeptides, Takeda, Karyopharm: Research Funding. Polepally:AbbVie: Current Employment, Other: may hold stock or stock options.. Motwani:AbbVie: Current Employment, Current equity holder in publicly-traded company. Mu:AbbVie: Current Employment, Other: may hold stock or stock options.. Salman:AbbVie: Current Employment, Other: may hold stock or stock options.. Penugonda:AbbVie: Current Employment, Other: may hold stock or stock options.. Moreau:Novartis: Honoraria; Sanofi: Consultancy, Honoraria; Celgene/Bristol-Myers Squibb: Consultancy, Honoraria; Janssen: Consultancy, Honoraria; Takeda: Honoraria; Amgen: Consultancy, Honoraria; Abbvie: Consultancy, Honoraria.

The Crimson 1 Study: A Phase 3 Study to Evaluate the Efficacy and Safety of Subcutaneous Marzeptocog Alfa (activated) for on-Demand Treatment and Control of Bleeding Episodes in Subjects with Hemophilia A or Hemophilia B, with Inhibitors

Background Hemophilia A (HA) and HB are X-linked bleeding disorders caused by a deficiency of Factor VIII (HA) or Factor IX (HB). A significant number of individuals with HA and HB develop inhibitors against the wild-type FVIII or FIX, respectively, and thereby become refractory to factor replacement treatment. Treatment of episodic bleeding in these individuals requires technical expertise to gain the requisite intravenous (IV) access and is often associated with pain. This causes delays in administration, which results in prolonged bleeding and accumulation of blood in the joint or other bleeding site. Currently approved FVIIa containing products take 6-24 hours to achieve hemostasis and maintain efficacy. Marzeptacog alfa (activated) (MarzAA), a novel variant activated recombinant Factor VII (rFVIIa), is being developed for subcutaneous (SQ) administration to address this important unmet need. Data from the Phase 1 study, MAA-102, demonstrated that SQ MarzAA is quickly absorbed and has the potential to achieve and maintain plasma levels in the desired range with an acceptable safety profile. This open-label, global, multi-center, randomized, cross-over Phase 3 study will evaluate the efficacy and safety of MarzAA for on demand treatment of spontaneous or traumatic bleeding episodes in adolescents and adults with congenital HA or HB with inhibitors. MarzAA will be compared to the Standard of Care (SOC). Approximately 60 subjects will be enrolled at 54 sites in 19 countries. Study Design and Methods Key inclusion criteria: Eligible male or female subjects ≥ 12 years of age must have: confirmed diagnosis of HA or HB unresponsive to or intolerant of standard replacement therapy; history of bleeding with annualized bleeding rate of ≥ 8; investigator-confirmed subject's ability to identify bleeding episodes and administer MarzAA SQ and infuse SOC IV at home. Key exclusion criteria: Subjects should not have had previous exposure to SQ administration of rFVIIa or exposure to any other variant rFVIIa; known positive antibody or hypersensitivity to MarzAA, FVIIa, or variants thereof; history of other coagulation disorder(s); platelet count <50,000/µL; CD4 T cell count <200 cells/mm3. Treatment: Subjects >17 years of age will be randomized in blocks to target treatment of approximately 5 bleeds with MarzAA and an additional 5 bleeds with SOC in either order, Sequence A or Sequence B, with a washout period to assess anti-drug antibodies (ADA) status between treatments. A total of 488 eligible bleeds will be treated, ~244 bleeds with each treatment, until ≥80% of patients have ≥3 bleeds treated with MarzAA and SOC. Pharmacokinetic samples will be collected during the MarzAA treatment period. Subjects 12-17 years of age will be enrolled after a positive DSMB assessment of 30 eligible bleeds treated with MarzAA. Subjects will administer 60 µg/kg SQ dose of MarzAA, at 3-hour intervals, for up to 3 doses as required to achieve hemostasis. Endpoints: Primary endpoint includes percentage of treated bleeds resulting in effective hemostasis (excellent or good) at 24 hours after the initial dose. Key secondary endpoints include time to cessation of bleeding after the initial dose; percentage of treated bleeds resulting in effective hemostasis at fixed timepoints; percentage of those that maintain hemostasis at 48 hours after the initial dose; use and amount of rescue therapy. Key safety endpoints include the incidence of adverse events; occurrence of thrombotic events and binding and/or neutralizing anti-drug antibodies. Key exploratory endpoints include assess patient satisfaction with the Treatment Satisfaction Questionnaire for Medicine- 9; assessment of pain using the Visual Analogue Scale; time required to administer treatment. Statistics: The goal is to demonstrate the true proportion of bleeds effectively treated with MarzAA is not inferior to SOC. Using a baseline efficacy of 85% for SOC, with a -12% margin of non-inferiority, treatment of 244 bleeds in each group provides 90% power with a one-sided 2.5% significance level to substantiate this result. Figure Disclosures Neuman: Catalyst Biosciences: Current Employment, Current equity holder in publicly-traded company. Desai:Catalyst Biosciences: Current Employment, Current equity holder in publicly-traded company. Knudsen:Catalyst Biosciences: Current Employment, Current equity holder in publicly-traded company. Del Greco:Catalyst Biosciences: Current Employment, Current equity holder in publicly-traded company. Levy:Catalyst Biosciences: Current Employment, Current equity holder in publicly-traded company.

Real-World Clinical Outcomes in Previously Untreated and Minimally Treated Patients with Congenital Factor VIII Deficiency: The San Diego Experience

Introduction: Emicizumab is a bi-specific, humanized, monoclonal antibody that mimics the function of activated Factor VIII (FVIII). It is approved for prophylaxis in persons of all ages with hemophilia A (HA) both with and without a FVIII inhibitor. The data on the use of emicizumab in previously untreated patients (PUPs) and minimally treated patients (MTPs) are scarce, with only one PUP reported in the pediatric clinical trials for the drug. The objective of this retrospective study was to describe our real-world institutional experience in prescribing emicizumab prophylaxis for PUPs and MTPs. Methods: This analysis includes six patients between 1-23 months of age with severe HA prescribed emicizumab prophylaxis at Rady Children's Hospital San Diego (RCHSD) Hemophilia and Thrombosis Treatment Center between November 2017 to April 2020. Data collected through April 2020 included demographics, inhibitor history, bleeding and treatment history prior to initiation of emicizumab prophylaxis, reason for initiation of emicizumab, age, weight, and dosing regimen at the beginning of emicizumab prophylaxis, bleeding and surgical history after initiation of emicizumab, and adverse reactions to emicizumab. Results: Our cohort of six patients included 1 PUP and 5 MTPs with less than 20 FVIII exposure days (ED) prior to the initiation of emicizumab prophylaxis. All MTPs patients were previously treated with on-demand treatment prior to the initiation of emicizumab. Demographic and clinical characteristics are shown in Table 1. The median age and weight at initiation of emicizumab were 8 months (range: 1 to 23 months) and 9.5 kg (range: 4.4 to 11.8 kg) respectively. One patient who was treated on-demand was diagnosed with a high-titer FVIII inhibitor in the setting of a mouth bleed and started emicizumab prophylaxis after bleed management. The most common reason for initiation of emicizumab prophylaxis in non-inhibitor patients was the ability to administer medication without reliable venous access. Following four once weekly loading doses with emicizumab, five patients continued weekly maintenance dosing and one patient continued every 28 day maintenance dosing. Patients were followed for a median of 9 months (range 3-24 months) after emicizumab initiation. Four patients, including the patient with a known FVIII inhibitor prior to starting emicizumab, had zero treated bleeds following initiation of emicizumab prophylaxis. Two patients were diagnosed with high-titer FVIII inhibitors on routine inhibitor surveillance after initiation of emicizumab prophylaxis and were the only patients who experienced treated bleeds during the study period. The majority (6 of 8) of treated bleeds were traumatic. The patient with the highest FVIII inhibitor titer experienced a disproportionately high number of the total treated bleeds though three of the seven bleeds were prior to FVIII inhibitor diagnosis. No patients required central venous catheter placement. One patient underwent circumcision with peri-operative FVIII replacement and did not have post-op bleeding. In terms of medication safety, one patient reported injection site bruising. No patient experienced severe adverse reactions including thrombotic microangiopathy, thrombosis, or clinical evidence of anti-drug neutralizing antibodies. All patients continued emicizumab prophylaxis during the study period. Conclusions: We found that prophylaxis with emicizumab is efficacious and well-tolerated in our cohort of young children with HA under the age of 24 months both with and without high-titer FVIII inhibitors. Two patients were diagnosed with high-titer FVIII inhibitors on routine surveillance after initiation of emicizumab prophylaxis, which highlights the importance of continuing FVIII inhibitor surveillance after initiation of emicizumab. More data are needed on the use of emicizumab, particularly in PUPs and MTPs, with regards to safety, efficacy, and prevention of inhibitors in this patient population. Disclosures Thornburg: American Thrombosis and Hemostasis Network: Research Funding; National Hemophilia Foundation: Membership on an entity's Board of Directors or advisory committees, Research Funding; Bayer Pharmaceuticals: Research Funding; Biomarin: Consultancy, Speakers Bureau; Genentech: Speakers Bureau; NovoNordisk: Research Funding; Sanofi Genzyme: Consultancy, Other: Data Safety Monitoring Board, Research Funding; Spark Therapeutics: Consultancy; Bluebird Bio: Consultancy; Ironwood Pharmaceuticals: Consultancy, Other: Data Safety Monitoring Board.

Strategies to develop highly drug-tolerant cell-based neutralizing antibody assay: neutralizing antidrug antibodies extraction and drug depletion.

Aim: Drug interference poses great analytical challenges for cell-based neutralizing antidrug antibodies (NAb) assay. The work aimed to improve assay drug tolerance through biotin-drug extraction with acid dissociation method optimization and developing new approach. Results: The NAb extraction with biotin-drug extraction with acid dissociation approach has been optimized by reducing biotinylated drug leaching and improving NAb elution efficiency, resulting in drug tolerance of up to 160μg/ml. To circumvent the low acid elution efficiency of NAb from drug, a novel drug depletion approach was developed, which combined acid dissociation and drug targeted crosslinked capture, achieved drug tolerance up to 400μg/ml. Atlast, a strategy workflow for sample pretreatment approach selection and optimization was established for improving drug tolerance of NAb assay. Conclusion: We demonstrated that reduced biotinylated drug leaching and the high NAb elution efficiency was critical for improving assay drug tolerance. Drug depletion offers an alternative approach to overcome low NAb elution efficiency.

Detailed epitope mapping of neutralizing anti-drug antibodies against recombinant α-galactosidase A in patients with Fabry disease

BackgroundFabry disease (FD) is a lysosomal storage disease, treatable by enzyme replacement therapy (ERT) that substitutes deficient α-galactosidase A (AGAL). The formation of neutralizing anti-drug antibodies (ADA) inhibiting AGAL activity is associated with disease progression in affected male patients. In the current study, we performed a detailed epitope mapping of ADAs from antibody-positive males against infused AGAL. MethodsA detailed epitope mapping for 34 male FD patients with neutralizing ADAs against AGAL was performed. Based on this data, in silico analyses were used to identify potential epitope clusters and mapped surface-located or buried epitopes. ELISA-based assays against α-galactosidase B (NAGA) were performed to identify ADAs that potentially recognize shared epitopes of AGAL and NAGA. A subset of 20 patients was analyzed to assess if NAGA-recognizing ADAs against AGAL might affect long-term outcomes under ERT. ResultsThirty percent of the AGAL active site was recognized by patients' ADAs. No differences between buried and surface-located epitopes were observed. Dependent on the epitopes, ADAs against AGAL were also able to recognize human NAGA. Patients with NAGA recognizing anti-AGAL antibodies presented with lower plasma NAGA activities. The presence of NAGA-recognizing ADAs had no effect on disease progression. ConclusionIn conclusion, our current data underline previous reports demonstrating a large variation of antibody epitopes against AGAL. Detailed epitope mapping in affected patients might be the first step for the generation of patient-specific blocking peptides and/or immune adsorption columns for an individually tailored anti-antibody strategy.