Incidence Of Anti-drug Antibodies Research Articles

Anti-Drug Antibody Incidence Comparison of Therapeutic Proteins Administered Via Subcutaneous vs. Intravenous Route.

Subcutaneous (SC) administration of therapeutic proteins is perceived to pose higher risk of immunogenicity when compared with intravenous (IV) route of administration (RoA). However, systematic evaluations of clinical data to support this claim are lacking. This meta-analysis was conducted to compare the immunogenicity of the same therapeutic protein by IV and SC RoA. Anti-drug antibody (ADA) data and controlling variables for 7 therapeutic proteins administered by both IV and SC routes across 48 treatment groups were analyzed. RoA was the primary independent variable of interest while therapeutic protein, patient population, adjusted dose, and number of ADA samples were controlling variables. Analysis of variance was used to compare the ADA incidence between IV and SC RoA, while accounting for controlling variables and potential interactions. Subsequently, 10 additional therapeutic proteins with ADA data published for both IV and SC administration were added to the above 7 therapeutic proteins and were evaluated for ADA incidence. RoA had no statistically significant effect on ADA incidence for the initial dataset of 7 therapeutic proteins (p = 0.55). The only variable with a significant effect on ADA incidence was the therapeutic protein. None of the other controlling variables, including their interactions with RoA, was significant. When all data from the 17 therapeutic proteins were pooled, there was no statistically significant effect of RoA on ADA incidence (p = 0.81). In conclusion, there is no significant difference in ADA incidence between the IV and SC RoA, based on analysis of clinical ADA data from 17 therapeutic proteins.

ASCT2-Targeting Antibody-Drug Conjugate MEDI7247 in Adult Patients with Relapsed/Refractory Hematological Malignancies: A First-in-Human, Phase 1 Study.

MEDI7247 is a first-in-class antibody-drug conjugate (ADC) consisting of an anti-sodium-dependent alanine-serine-cysteine transporter 2 antibody-conjugated to a pyrrolobenzodiazepine dimer. This first-in-human phase 1 trial evaluated MEDI7247 in patients with hematological malignancies. Adults with acute myeloid leukemia (AML), multiple myeloma (MM), or diffuse large B-cell lymphoma (DLBCL) relapsed or refractory (R/R) to standard therapies, or for whom no standard therapy exists, were eligible. Primary endpoints were safety and determination of the maximum tolerated dose (MTD). Secondary endpoints included assessments of antitumor activity, pharmacokinetics (PK), and immunogenicity. As of 26 March 2020, 67 patients were treated (AML: n = 27; MM: n = 18; DLBCL: n = 22). The most common MEDI7247-related adverse events (AEs) were thrombocytopenia (41.8%), neutropenia (35.8%), and anemia (28.4%). The most common treatment-related grade 3/4 AEs were thrombocytopenia (38.8%), neutropenia (34.3%), and anemia (22.4%). Anticancer activity (number of responders/total patients evaluated) was observed in 11/67 (16.4%) patients. No correlation was observed between ASCT2 expression and clinical response. Between-patient variability of systemic exposure of MEDI7247 ADC and total antibody were high (AUCinf geometric CV%: 62.3-134.2, and 74.8-126.1, respectively). SG3199 (PBD dimer) plasma concentrations were below the limit of quantification for all patients after Study Day 8. Anti-drug antibody (ADA) prevalence was 7.7%, ADA incidence was 1.9%, and persistent-positive ADA was 5.8%. Thrombocytopenia and neutropenia limited repeat dosing. Although limited clinical activity was detected, the dose-escalation phase was stopped early without establishing an MTD. The study was registered with ClinicalTrials.gov (NCT03106428).

"Getting the Dose Right"-Revisiting the Topic With Focus on Biologic Agents.

Nearly two decades after the Peck and Cross article '"Getting the dose right: facts, a blueprint, and encouragements" was published, a review of dose recommendations for biologics shows that the success in getting the dose right appears to have improved given the relatively low incidence of drug withdrawals and dosing/label changes. However, the clinical experience with monoclonal antibodies (MAbs) following approval has been less than perfect. In inflammatory diseases, the disease burden changes with time and high treatment failure rates have been reported. In addition, the use of concomitant steroids and immunosuppressant drugs with MAbs is common. These concomitant agents have their own safety issues and many immunosuppressant agents are not well-tolerated although they have been shown to reduce the incidence of anti-drug antibodies (ADA). This same complexity is seen in MAbs used in oncology as well, although with these agents the doses appear to be higher than needed, which results in high treatment costs and incidence of adverse events. Given the complexity of MAb pharmacokinetics, which makes providing a detailed description of dose options difficult, product labeling should include the options for alternative dose strategies and potentially include the use of therapeutic drug monitoring with dose individualization which have been shown to improve clinical response and reduce the incidence of ADA. So, while the recommended dosing for biologics seems improved over the issues noted 17 years ago, we still have some work to do.

P127 Comparison of the Efficacy, Safety and Immunogenicity of a Proposed Biosimilar MSB11456 with Tocilizumab Reference Product in Moderate-to-Severe Rheumatoid Arthritis: Results of a Randomized Double-Blind Study

Abstract Background/Aims Tocilizumab is an anti-interleukin-6 receptor monoclonal antibody indicated for treating rheumatoid arthritis (RA) and other inflammatory diseases. MSB11456 is a proposed biosimilar to US-licensed tocilizumab and EU-approved tocilizumab. It has already shown equivalent pharmacokinetic, pharmacodynamic safety, tolerability, and immunogenicity profiles to these products given subcutaneously (SC) as a single dose in healthy volunteers. This Phase III, multi-centre, randomised, double-blind, multiple fixed-dose, parallel group study compared efficacy, safety and immunogenicity of MSB11456 and EU-approved tocilizumab administered SC in moderate-to-severe RA patients. Methods Patients were randomised to 162mg MSB11456 or EU-approved tocilizumab for 24 weeks (W). At W24, patients receiving EU-approved tocilizumab were re-randomised to continue treatment or switch to MSB11456 for up to W52. Safety evaluations were conducted up to W63. A change from baseline in Disease Activity Score-28 Joint Count-ESR (DAS28-ESR) at W24 was analysed, as the primary efficacy endpoint, using analysis of covariance to determine the least squares mean (LSM) difference between MSB11456 and EU-approved tocilizumab; equivalence was considered if the 90% confidence interval (CI) was entirely within the FDA equivalence interval -0.6 to 0.5. Secondary endpoints were 20% improvement in ACR core set measures at W24 and DAS28-ESR at W12. Additional endpoints included ACR50/70, change in DAS28-CRP, Simplified and Clinical Disease Activity Indexes, evaluation of immunogenicity up to W55 and safety up to W63. Results Clinically relevant LSM decreases from baseline in DAS28-ESR were observed from W2 up to W24 with both treatments. The 90% CI for LSM difference in the change from baseline in DAS28-ESR between treatments was fully included within the predefined equivalence interval, which demonstrated therapeutic equivalence of MSB11456 and EU-approved tocilizumab (Table 1). Other efficacy endpoint analyses supported this conclusion. No discernible patterns in the nature or frequency of treatment-emergent adverse events (TEAEs) were identified to suggest a difference between drugs. Anti-drug antibodies incidence was similar among treatment arms. Switching from EU-approved tocilizumab to MSB11456 had no clinically relevant impact on efficacy or safety. Conclusion Equivalent efficacy, immunogenicity and safety profiles of MSB11456 and EU-approved tocilizumab were demonstrated in moderate-to-severe RA patients, confirming equivalence between MSB11456 and the EU-approved tocilizumab. Disclosure A. Zubrzycka-Sienkiewicz: None. M. Misterska-Skora: None. M. Socik-Pojawa: None. K. Klama: None. M. Ullman: Other; Employee of Fresenius Kabi SwissBioSim - Sponsor of the study. C. Petit-Frere: Other; Employee of Fresenius Kabi SwissBioSim - Sponsor of the study. A. Illes: Other; Employee of Fresenius Kabi SwissBioSim - Sponsor of the study. P. Baker: Other; Employee of Fresenius Kabi SwissBioSim - Sponsor of the study. J. Monnet: Other; Employee of Fresenius Kabi SwissBioSim - Sponsor of the study. J. Morais: Other; Employee of Fresenius Kabi SwissBioSim - Sponsor of the study. J. Brzezicki: None.

Abstract CT077: An open-label phase 1 study to investigate SGN-CEACAM5C in adults with advanced solid tumors (SGNCEA5C-001, Trial in Progress)

Abstract Background Patients (pts) with recurrent or metastatic solid tumors, including non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), colorectal cancer (CRC), gastric adenocarcinoma (GC), and pancreatic ductal adenocarcinoma (PDAC), have limited treatment options with short PFS and OS despite recent advances (Bordry 2021; Chakrabarti 2022; Merle 2022). Carcinoembryonic antigen-related cell adhesion molecule 5 (CEACAM5) is highly expressed across multiple solid tumors, such as CRC, GC, PDAC, and NSCLC. Restricted normal tissue expression and efficient lysosomal trafficking of CEACAM5 highlight its potential as an anticancer target. SGN-CEACAM5C is a novel investigational antibody-drug conjugate (ADC) directed to CEACAM5 composed of the humanized immunoglobulin G (IgG1) anti-CEACAM5 monoclonal antibody tusamitamab chemically conjugated to 8 molecules of the topoisomerase 1 inhibitor 7-aminomethyl-10,11-methylenedioxycamptothecin (AMDCPT). SGN-CEACAM5C selectively binds to CEACAM5 present on the cell surface and is internalized via the endo-lysosomal pathway, with subsequent release of the payload through enzymatic cleavage. Release of the cytotoxic payload induces DNA damage, cell cycle arrest in S phase, and apoptosis in tumor cells. In vitro bystander activity was observed against tumor cells without CEACAM5 surface expression. SGN-CEACAM5C is highly active in multiple patient-derived xenograft models, including CRC, GC, and NSCLC, across various levels of CEACAM5 expression (Baudat 2023; Baudat 2024). These preclinical findings justify evaluation of SGN-CEACAM5C in a clinical trial setting. Methods SGNCEA5C-001 (NCT06131840) is a phase 1, open-label, multicenter study designed to characterize the safety, tolerability, pharmacokinetics (PK), pharmacodynamics (PD), and preliminary antitumor activity of SGN-CEACAM5C in adults with select advanced solid tumors. This study consists of dose escalation (Part A), dose and schedule optimization (Part B), and dose expansion (Part C). Eligible pts are adults ≥18 years of age with confirmed metastatic or unresectable solid tumor malignancy, measurable disease per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1, an ECOG PS of 0-1, and 1 of the following tumor types: CRC, GC/gastroesophageal junction adenocarcinoma (GEJ), PDAC, NSCLC (squamous/non-squamous), or SCLC. Primary endpoints include incidence of AEs, laboratory abnormalities, dose modifications due to AEs, dose-limiting toxicities, and cumulative safety. Secondary endpoints include estimates of PK parameters, incidence of antidrug antibodies, objective response rate and best response per RECIST v1.1 by investigator, duration of response, PFS, and OS. Safety and antitumor activity endpoints will be summarized using descriptive statistics. Recruitment is ongoing for Part A in North America. Citation Format: Funda Meric-Bernstam, Cesar A. Perez, Nehal Lakhani, Meredith Pelster, Justin Call, Suzanne McGoldrick, Tianhua Wang, Brigitte Demers, Amita Patnaik. An open-label phase 1 study to investigate SGN-CEACAM5C in adults with advanced solid tumors (SGNCEA5C-001, Trial in Progress) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 2 (Late-Breaking, Clinical Trial, and Invited Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(7_Suppl):Abstract nr CT077.

A Randomized, Double-blind, Phase III Study Assessing Clinical Similarity of SB17 (Proposed Ustekinumab Biosimilar) to Reference Ustekinumab in Subjects with Moderate to Severe Plaque Psoriasis

Ustekinumab is a safe and effective treatment for moderate-to-severe psoriasis. To compare efficacy, safety, pharmacokinetics (PK), and immunogenicity of the proposed ustekinumab biosimilar SB17 with reference ustekinumab (UST) in subjects with moderate to severe plaque psoriasis. In this randomized double-blind study, subjects were randomized to receive 45 mg of SB17 or UST subcutaneously at Week 0, 4, and every 12 weeks. The primary endpoint was the percent change from baseline in Psoriasis Area and Severity Index (PASI) at Week 12 with an equivalence margin of [-15%, 15%]. Other secondary efficacy, safety, PK, and immunogenicity endpoints were measured through Week 28. 249 subjects were randomized to SB17, 254 to UST. Adjusted difference of PASI change from baseline at Week 12 of -0.6% (95% confidence interval [CI; -3.780, 2.579]) was within the equivalence margin. Physician's Global Assessment (PGA) and Dermatology Life Quality Index (DLQI) were also comparable. Overall treatment-emergent adverse events (TEAEs) were comparable (SB17: 48.2%, UST: 48.8%). The overall incidence of anti-drug antibodies (ADAs) up to Week 28 was 13.3% with SB17 and 39.4% with UST. Data were only through Week 28. SB17 was clinically biosimilar to UST up to Week 28.

Implications of Immunogenicity Testing for Therapeutic Monoclonal Antibodies: A Quantitative Pharmacology Framework

The interpretation of immunogenicity results for a mAb product and prediction of its clinical consequences remain difficult, despite enormous advances in methodologies and efforts toward the best practice for consistent data generation and reporting. To this end, the contribution from the clinical pharmacology discipline has been largely limited to comparing descriptively the pharmacokinetic (PK) profiles by antidrug antibodies (ADA) status or testing the significance of ADA as a covariate in a population PK setting, similar to the practice for small-molecule drugs in investigating the effect of an intrinsic/extrinsic factor on the drug disposition. There is a need for a mAb disposition framework that captures the dynamics of ADA formation and drug’s interactions with the ADA and target as parts of the drug distribution and elimination. Here we describe such a framework and examine it against the PK, ADA, and clinical response data from a phase 3 trial in patients treated with adalimumab. The proposed framework offered a generalized understanding of how the dose, target affinity, and drug/ADA analyte forms affects the manifestation of ADA response with regard to its detections and alterations of drug disposition and effectiveness. Furthermore, as an example, its utility for dose considerations was demonstrated through predicting for late-stage trials of a PCSK9 inhibitor in terms of development in ADA incidence and titers, and consequences on the drug disposition, interaction with target, and downstream lowering effect on LDL-C.Graphical

Strategy and validation of a nonclinical generic plug-and-play antidrug antibody method for human monoclonal antibody biotherapeutics.

The measurement of antidrug antibodies (ADA) in nonclinical studies provides limited value becausethe formation and incidence of nonclinical ADA does not translate to clinical experience. The formation and presence of ADA in nonclinical species can, however, correlate to reduced drug exposure and safety observations including vasculitis and immune complex disease. Generic ADA methods for humanized monoclonal antibody biotherapeutics mitigate the need to develop bespoke ADA methods during nonclinical drug development. A drug-tolerant, sensitive, generic ADA immunoassay has been developed and validated for measuring ADA in cynomolgus monkey serum samples, allowing for immediate qualification of future monoclonal antibody biotherapeutics. This approach allows us to differentiate complexed and free ADA in a rapidly deployable manner when needed.

Obinutuzumab Pretreatment as a Novel Approach to Mitigate Formation of Anti-Drug Antibodies Against Cergutuzumab Amunaleukin in Patients with Solid Tumors.

The immunocytokine cergutuzumab amunaleukin (CEA-IL2v) showed manageable safety and favorable pharmacodynamics in phase I/Ib trials in patients with advanced/metastatic carcinoembryonic antigen-positive (CEA+) solid tumors, but this was accompanied by a high incidence of anti-drug antibodies (ADA). We examined B-cell depletion with obinutuzumab as a potential mitigation strategy. Preclinical data comparing B-cell depletion with rituximab versus obinutuzumab are summarized. Substudies of phase I/Ib trials investigated the effect of obinutuzumab pretreatment on ADA development, safety, pharmacodynamics, and antitumor activity of CEA-IL2v ± atezolizumab in patients with advanced/metastatic or unresectable CEA+ solid tumors who had progressed on standard of care. Preclinical data showed superior B-cell depletion with obinutuzumab versus rituximab. In clinical studies, patients received CEA-IL2v monotherapy with (n = 16) or without (n = 6) obinutuzumab pretreatment (monotherapy study), or CEA-IL2v + atezolizumab + obinutuzumab pretreatment (n = 5; combination study). In the monotherapy study, after four cycles (every 2 weeks treatment), 0/15 evaluable patients administered obinutuzumab pretreatment had ADAs versus 4/6 patients without obinutuzumab. Obinutuzumab pretreatment with CEA-IL2v monotherapy showed no new safety signals and pharmacodynamic data suggested minimal impact on T cells and natural killer cells. Conversely, increased liver toxicity was observed in the combination study (CEA-IL2v + atezolizumab + obinutuzumab pretreatment). These preliminary findings suggest that obinutuzumab pretreatment before CEA-IL2v administration in patients with CEA+ solid tumors may be a feasible and potent ADA mitigation strategy, with an acceptable safety profile, supporting broader investigation of obinutuzumab pretreatment for ADA mitigation in other settings.

A Retrospective Analysis of the Potential Impact of Differences in Aggregates on Clinical Immunogenicity of Biosimilars and their Reference Products.

Aggregates, in particular high molecular weight species (HMWs), have been linked to increased immunogenicity. The current understanding on the impact of HMWs is mainly based on in vitro and nonclinical studies and there are only limited data available associating differences in HMWs in marketed monoclonal antibodies (mAbs) to clinical outcomes. Biosimilars offer a unique opportunity to study the potential association between quality parameters and clinical outcomes. We performed a retrospective evaluation to investigate the association between HMW content and reported antidrug-antibody (ADA) incidence in 30 full-length biosimilar mAbs approved in the European Union and the United States. Information for HMW content and ADA incidence were collected from publicly available sources. Differences in HMW content between biosimilars and their reference products (RPs) ranged from -0.75 to 1.65% with slightly higher differences observed in antineoplastic products as compared with immunosuppressant products. The difference in the ADA incidence between the RP and the biosimilar for the programs studied ranged from -11.0 to 18.5%. No association was observed between differences in HMW content and reported ADA incidence, in neither phase I nor phase III studies. Our results show that the limited differences in the content of HMWs between marketed biosimilars and reference mAbs were not associated with differences in reported immunogenicity, determined as incidence of ADAs and neutralizing ADAs in comparative clinical studies.

Treatment-emergent antidrug antibodies related to PD-1, PD-L1, or CTLA-4 inhibitors across tumor types: a systematic review

BackgroundIncreased understanding of how the immune system regulates tumor growth has innovated the use of immunotherapeutics to treat various cancers. The impact of such therapies, including programmed cell death protein...

Safety, Tolerability, Pharmacokinetics, and Immunogenicity of the Anti-IFNAR1 Monoclonal Antibody QX006N: A First-in-Human Single Ascending Dose Study in Healthy Chinese Volunteers.

QX006N is a novel, humanized, IgG4κ monoclonal antibody targeting IFNAR1, developed for the treatment of systemic lupus erythematosus. This study aims to investigate the pharmacokinetics, safety, tolerability, and immunogenicity of QX006N when administered intravenously to healthy Chinese individuals. A double-blind, randomized, placebo-controlled, single-ascending-dose, phase I clinical trial was conducted comprising five cohorts (n = 10 per cohort, except n = 5 for the first cohort). Subjects in each cohort were randomly assigned in a 4:1 ratio to receive a single intravenous infusion of QX006N (0.3 mg/kg, 1.0 mg/kg, 3.0 mg/kg, 6.0 mg/kg, or 10.0 mg/kg) or placebo for 30 minutes. Tolerability assessments included adverse events, vital signs, 12-lead electrocardiogram, physical examination, and clinical laboratory tests. The serum concentration of QX006N was measured using the enzyme-linked immunosorbent assay method, and the anti-drug antibodies were detected using the electrochemiluminescence assay method. QX006N demonstrated a favorable safety and tolerability profile throughout the study. All treatment-emergent adverse events were of Grade 1-2 (CTCAE Version 5.0), and no serious adverse events, deaths, or drug discontinuations because of treatment-emergent adverse events were observed. All drug-related treatment-emergent adverse events showed no clear dose-related trends. Following an intravenous infusion of QX006N at doses that ranged from 0.3 mg/kg to 10 mg/kg, the half-life increased from 24.7 to 208 hours in a dose-dependent manner, while clearance decreased from 0.0828 to 0.0065 L/h. The maximum concentration exhibited nearly dose-proportional increases, and the area under the curve displayed a more than dose-proportional increment with non-linear pharmacokinetic characteristics. The incidence of anti-drug antibodies was observed to increase over time for doses that ranged from 1.0 mg/kg to 10.0 mg/kg of QX006N, reaching its peak at day 57 (range 62.50-87.50%). Conversely, the incidence of anti-drug antibodies in the QX006N 0.3-mg/kg and placebo cohorts remained low. QX006N demonstrated acceptable safety, tolerability, and pharmacokinetic characteristics in healthy subjects when administered as a single intravenous infusion at doses that ranged from 0.3 mg/kg to 10.0 mg/kg. Based on the pharmacokinetic and safety outcomes, a recommended effective dose of 300 mg is proposed for future phase Ib studies. This study has been registered at http://www.chinadrugtrials.org.cn/ under identifier CTR20212834.

Safety and Tolerability of Inclisiran forTreatment of Hypercholesterolemia in7 Clinical Trials.

Inclisiran is a small interfering RNA agent to lower low-density lipoprotein cholesterol. The purpose of this study was to provide reliable evidence to date on the long-term safety profile of inclisiran. This post hoc analysis comprised patients treated with 300mg inclisiran sodium or placebo in the completed (ORION-1, -3, -5, -9, -10, and -11) and ongoing (ORION-8) trials. Exposure-adjusted incidence rates and Kaplan-Meier estimates of cumulative incidence of reported treatment-emergent adverse events (TEAE), abnormal laboratory measurements, and incidence of antidrug antibodies were analyzed. This analysis included 3,576 patients treated with inclisiran for up to 6 years and 1,968 patients treatedwith placebo for up to 1.5 years, with 9,982.1 and 2,647.7 patient-years of exposure, respectively. Baseline characteristics were balanced between groups. Kaplan-Meier analyses showed that TEAEs that were serious or led to discontinuation; hepatic, muscle, and kidney events; incident diabetes; and elevations of creatine kinase or creatinine accrued at a comparable rate between groups for up to 1.5 years, with similar trends continuing for inclisiran beyondthis period. Numerically fewer major cardiovascular events reported as TEAEs occurred with inclisiran during this period. Treatment-induced antidrug antibodies were uncommon with inclisiran (4.6%), with few of these persistent (1.4%) and not associated with greater incidence of TEAEs leading to study drug discontinuation or serious TEAEs. Long-term treatment with inclisiran was well tolerated in a diverse population, without new safety signals, supporting the safety of inclisiran in patients with dyslipidemia.

Abstract LB_A17: Trial in progress: First-in-human phase I dose-escalation study of a novel Bicycle toxin conjugate (BT5528) targeting EphA2 in patients with advanced solid tumors

Abstract Background: Bicycles are a novel class of synthetic molecules formed by short linear peptides constrained in a stabilized bi-cyclic structure that can be conjugated to other molecules. BT5528 is a Bicycle Toxin Conjugate, comprising a bicyclic peptide targeting EphA2 linked to a cytotoxin (monomethyl auristatin E [MMAE]). EphA2 is expressed at low levels in normal tissues but overexpressed in many solid tumors; EphA2 expression correlates with malignant progression and poor patient outcome. BT5528 is ~40X smaller than antibody-drug conjugates (ADCs) and has the potential to penetrate solid tumors. Within the tumor, release of MMAE disrupts intracellular microtubule dynamics leading to inhibited proliferation and tumor cell death with bystander killing effect. The pharmacokinetic (PK) profile of BT5528 is distinct from ADCs with lack of Fc-mediated non-specific uptake, fast distribution, and renal elimination, leading to lower vascular exposure and potentially reduced toxicity in non-target tissues. The preclinical profile supported the initiation of a first-in-human study to investigate BT5528 safety and efficacy in advanced solid tumors with EphA2 expression (NCT04180371). Methods: This phase 1/2 multicenter, open-label trial evaluates BT5528 as monotherapy and in combination with nivolumab (nivo) in up to 288 patients. Phase 1 employs a 3+3 dose-escalation design for the first two dose levels followed by a Bayesian logistic regression model. Phase 2 expansion will test the selected dose(s) of BT5528 in six tumor-specific cohorts with high EphA2 expression (NSCLC, ovarian, TNBC, gastric/upper GI, head and neck, and urothelial cancer). BT5528 will be administered intravenously (IV) in ascending doses either weekly or every other week as monotherapy in Part A-1 and in combination with nivo in Part A-2 (480 mg of IV nivo every 4 weeks or 240 mg every 2 weeks), and as per the recommended phase 2 dose(s) (RP2D) in Part B. Part A patients must have a metastatic solid tumor type known to have high EphA2 tumor expression and Part B patients must have one of the specified tumor types; all patients must have failed or be ineligible for appropriate treatment options with evidence of radiographic progression on the most recent line of therapy. Additional eligibility criteria include ≥18 years of age, ECOG performance status of 0 or 1, and adequate organ function. Primary objectives for Part A are safety and tolerability and to define the maximum tolerated dose (if observed) and RP2D(s) as monotherapy and in combination with nivo. The primary objective for Part B is to assess clinical activity of BT5528 monotherapy. Secondary objectives include preliminary efficacy (Part A), safety and tolerability (Part B), correlation of EphA2 expression with efficacy (Part B), PK parameters of BT5528 and MMAE, and incidence of anti-drug antibodies. Tumor and blood samples will be collected for biomarker evaluations including tumor EphA2 expression, ADAs, and candidate response biomarkers for BT5528 alone and in combination with nivo. This study is actively recruiting. Citation Format: Elisa Fontana, Babar Bashir, Judy S. Wang, Raid Aljumaily, Jean-Pascal Machiels, Maria Vieito, Gerald Falchook, Louise Carter, Bernard Doger de Spéville, Alastair Greystoke, Sang Wun Kim, Nuria Kotecki, Alexander I. Spira, Irene Moreno Candilejo, Bristi Basu, Hans Prenen, Alberto Bessudo, Misako Nagasaka, Jordi Rodón Ahnert, Joo-Hwan Park, Min-Yuen Teo, Julia Rotow, Jie Liu, Assunta De Rienzo, Mengyao Li, Adriana Domingo, Hanna Orr, Gavin Bennett, Rajiv Sharma, Meredith McKean. Trial in progress: First-in-human phase I dose-escalation study of a novel Bicycle toxin conjugate (BT5528) targeting EphA2 in patients with advanced solid tumors [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr LB_A17.

Dose Escalation of HLA-A2-WT1 CD3 T-Cell Bispecific Antibody in a Phase I Study in Patients with Relapsed/Refractory Acute Myeloid Leukemia (AML)

Background: RO7283420 (RG6007) is a 2+1 TCR-like (TCR-L) T-cell bispecific (TCB) antibody targeting CD3 and the RMFPNAPYL peptide of Wilms Tumor 1 (WT1) protein presented by the major histocompatibility complex-I HLA-A*02 on acute myeloid leukemia (AML) blasts and other antigen presenting cells. The pre-clinical evaluation of RO7283420 in our in vivo humanized AML xenografts and ex vivo AML co-culture models showed strong T-cell mediated AML cell killing (Augsberger C, et al. Blood 2021). A Phase 1 dose-escalation (DE) study (NCT04580121) evaluated the safety, tolerability, pharmacokinetics, anti-drug antibodies (ADAs), and anti-leukemic activity of RO7283420 in patients with relapsed/refractory (R/R) AML. Methods: In this open-label, multi-center study, DE was performed using a 3+3 design. Patients received RO7283420 every 3 weeks (Q3W, n=46), or every week (QW, n=4) as intravenous (IV) infusions. Preliminary anti-leukemic activity included response assessment according to European Leukemia Net (ELN) response categories (adapted from Döhner H, et al. Blood 2017). Results: As of 13 April 2023, 50 HLA-A2+ R/R AML patients received at least one dose of RO7283420. Patients had a median age of 65.5 years (range 35-84), presented with ECOG of 0 (56%) or 1 (38%) or 2 (6%), and 58% were male. Median prior line of therapy was 2 (range 1-5). Overall, 58% of patients had relapsed and 42% had primary refractory disease. According to the ELN 2017 risk stratification, patients were of adverse (48%), intermediate (38%) or favorable (8%) risk category, for 6% of patients the risk category missing. The most common genetic abnormalities reported were RUNX1 (21%), ASXL1 (17%), TP53 (10.6%), FLT3-ITD (6.4%) and NPM1 (6.4%) of the 47 patients tested. Median bone marrow blast percentage at baseline was 35% (range 3-90%), while the median of circulating blast was 17% (range 0-88%). Study patients received RO7283420 IV at 13 different dose levels, ranging from a Minimum Anticipated Biological Effect Level (MABEL) of 0.15 mg (flat) to 18 mg Q3W (with a preceding weekly 1/3 mg ‘double step-up’ during Cycle 1) and one QW dose level with 9 mg preceded by a 1/3 mg step-up. Maximum tolerated dose was reached at 1/3/12 mg double step-up Q3W. Explored alternative QW schedule was not tolerable at 1/3/9 mg. The most common (≥20%) adverse events (AEs) were cytokine release syndrome (CRS) occurring in 34 (68%), pneumonia 14 (28%), pyrexia 13 (26%), febrile neutropenia 13 (26%), hyperglycemia 12 (24%), hypokalemia 11 (22%), and nausea 10 (20%) of patients. Eight dose limiting toxicities (DLTs) were reported: five G3 CRS (at 1/3, 2/12, 1/6/12 mg dose levels), G3 stomatitis (at 1/3/12 mg), G3 myositis (at 1/3/18 mg), and G4 thrombocytopenia (at 1/3/18 mg). Eleven patients (22%) experienced Grade 5 AEs with pneumonia, sepsis, and hemophagocytic lymphohistiocytosis (HLH) reported in >1 patient; all Grade 5 events were considered unrelated to RO728342 except 1 (at 1/3/9 mg) of 2 HLH events. IV PK has been overall dose-linear and characterized by a terminal half-life of 29 to 84 hours and a clearance of 58 to 92 mL/h. Preliminary ADA incidence within the study population was 19%. In the dose ranges tested, a trend for study drug exposure-dependent blast reduction was observed in blood, while a clear exposure-response relationship could not be established with BM blast reduction. Furthermore, our preliminary pharmacodynamic analysis identified expansion of naive and memory CD8 T cells in blood and activated CD8+ T cells in bone marrow, in line with the expected mode of action (MoA) of RO7283420. Preliminary efficacy signals were observed with 3 complete responses (CR), including 1 CR with incomplete blood count recovery. Conclusions: RO7283420 is the first TCR-L TCB antibody evaluated in AML. We observed pharmacodynamic evidence of T-cell activation and expansion in the clinic, in line with the expected MoA of TCBs, however, at the explored doses, no clear exposure-response relationship and only a modest clinical activity were observed. The safety profile was shown to be consistent with the other TCBs and R/R AML population. Based on the totality of data, the study was discontinued.

Pharmacokinetics and Immunogenicity of Abbv-383, a B-Cell Maturation Antigen (BCMA) × CD3 Bispecific T-Cell-Redirecting Antibody, in Patients with Relapsed/Refractory Multiple Myeloma (RRMM)

Introduction ABBV-383 is a fully human, silenced Fc region IgG4 monoclonal, BCMA × CD3 T-cell-engaging bispecific antibody with 2 BCMA-binding domains and a low-affinity CD3-binding domain. ABBV-383 has shown promising activity following intravenous (IV) infusion every three weeks (Q3W) as monotherapy in patients (pts) with RRMM in an ongoing phase 1 study (D'Souza A, et al. J Clin Oncol. 2022 Nov 1;40(31):3576-3586; Voorhees et al. Blood 2022;140[suppl 1]:4401). Herein, preliminary pharmacokinetic (PK) and immunogenicity results from Q3W regimens of this study and impact of soluble BCMA (sBCMA) on ABBV-383 PK are reported. Methods In the phase 1 study (NCT03933735), adult pts with RRMM, who were previously exposed to ≥3 prior multiple myeloma agents including ≥1 proteasome inhibitor, immunomodulatory drug, and anti-CD38 monoclonal antibody, received Q3W IV infusion at doses 0.025 - 120 mg in escalation (ESC) phase, and at 20 mg, 40 mg, and 60 mg in expansion (EXP) phase. Serial blood samples for PK characterization were collected in cycles 1, 3, and 6 along with sparse/periodic samples throughout the study. Blood samples were also collected throughout the study to detect anti-drug antibodies (ADAs) for immunogenicity characterization and to determine sBCMA concentrations. Appropriate validated assays were used to determine ‘total’ (unbound and bound to sBCMA) and ‘free’ (unbound and partially bound to sBCMA) ABBV-383 serum concentrations, to detect/determine ADAs/titers, and to determine total sBCMA concentrations. ‘Total’ and ‘free’ ABBV-383 serum concentrations from cycles 1, 3, and 6 were used to calculate individual PK parameters (peak concentration [C max], trough concentration [C trough], area under the concentration-time curve [AUC], terminal phase elimination half-life [t 1/2], clearance [CL], and steady state volume of distribution [V ss]) using non-compartmental analysis in Phoenix WinNonlin Version 8.2. Immunogenicity was summarized using ADA/titer data. Impact of baseline/pre-dose sBCMA concentrations on ‘total’ and ‘free’ ABBV-383 PK parameters from cycles 1, 3, and 6 was explored. Results ‘Total’ and ‘free’ ABBV-383 intensive PK data (cycles 1, 3, and 6) were available from 169 and 157 pts, respectively, representing Q3W regimens in ESC and EXP cohorts and ADA data were available from 186 evaluable subjects. Preliminary PK results suggest that ‘total’ and ‘free’ ABBV-383 exhibited approximately dose-proportional PK between 5.4-120 mg Q3W. Estimated t 1/2 for ‘total’ and ‘free’ ABBV-383 ranged between 11-12 days and 8-11 days, respectively, with steady state achieved by cycle 4 in Q3W EXP cohorts. Estimated CL and V ss were consistent with those of a typical IgG4 antibody in humans. Across EXP Q3W regimens, accumulation (cycle 3 vs. cycle 1) was 30%-60% in C max and 60%-177% in C trough for ‘free’ and ‘total’ ABBV-383. ABBV-383 exposures (AUC tau and C trough) of ‘total’ ABBV-383 were 28-74% higher than those representing ‘free’ ABBV-383 among the EXP Q3W regimens with no/minimal observed differences in C max (≤21%). Higher sBCMA levels prior to treatment appeared to reduce ‘free’ ABBV-383 PK exposures with pronounced reduction at lower doses (e.g., 20 mg) and in cycle 1, however the effect diminished in later cycles (cycles 3 and 5). Preliminary assessment of immunogenicity indicated an ADA incidence of 3.8% (7/186) with low titers ranging between 11.7 and 187 titer units and no impact on PK. Conclusions ABBV-383 exhibited a PK profile with relatively long half-life and low incidence of immunogenicity. Overall, sBCMA impacted (reduced) the ‘free’ ABBV-383 (pharmacologically active component) PK exposures only, with pronounced effect at lower doses and the effect is consistent with understanding of treatment dependent sBCMA dynamics over time. Determination of both ‘total’ and ‘free’ ABBV-383 serum concentrations allowed to demonstrate such underlying impact of sBCMA on PK.

Comparison of Efficacy and Safety of a Bevacizumab Biosimilar, in Combination with Chemotherapies, in Nonresectable Metastatic Colorectal Cancer and in Advanced Nonsquamous Non-Small Cell Lung Cancer: A Randomized, Double-Blind, Phase III Study.

Ranjith K.The objective of this study was to compare the efficacy, safety, pharmacokinetics, and immunogenicity of a proposed bevacizumab biosimilar (DRL_BZ) with the innovator Avastin (reference medicinal product [RMP]) in patients with nonresectable metastatic colorectal cancer (mCRC) over a period of 9 months and advanced nonsquamous non-small cell lung cancer (NSCLC) over 6 months. The study was planned as a randomized, double-blind trial. In part A, a total of 117 mCRC patients were intended to receive 5 mg/kg of bevacizumab every 2 weeks along with mFOLFOX6 chemotherapy for a maximum of 18 cycles. In part B, 60 NSCLC patients were to receive 15 mg/kg of bevacizumab every 3 weeks along with pemetrexed and carboplatin for the initial four cycles, followed by pemetrexed for another four cycles. The primary endpoint was the progression-free survival rate at 6 months (PFS6) in both subparts. The anticipated sample size was 106 evaluable mCRC patients to achieve 85% statistical power for concluding noninferiority with a margin of half the difference (18.8%) between DRL_BZ and Avastin, along with a pilot study involving 60 evaluable NSCLC patients. Safety comparison included assessing adverse events (AEs), infusion reactions, and lab abnormalities. Immunogenicity comparison involved the incidence of antidrug antibodies (ADAs) and neutralizing antibodies (NAbs). Pharmacokinetic comparison was planned after the first and fourth dosing cycles of treatment in 24 NSCLC patients. The PFS6 for mCRC patients treated with DRL_BZ and RMP was 57.8% and 50% respectively, with a difference in efficacy of 7.8 (-8.7, 23.7). The PFS9 was 31.1% and 22.9%, with a difference of 8.2% (-6.9%, 22.9%). The objective response rate (ORR) for DRL_BZ and RMP was 28.8% and 22.4%, while the disease control rate (DCR) was 44.2% and 37.9% respectively. For NSCLC patients, the PFS6 was 44% and 45%, showing a difference of -1.0 (-4.2, 22.1). The ORR was 41.4% and 48.1%, and the DCR was 62.1% and 63%. The frequency, type, and severity of AEs were similar in both indications. Blood levels during the first and fourth dosing cycles exhibited comparable values. All NSCLC patients tested negative for ADA, while no mCRC patients on DRL_BZ tested positive for ADA. Low incidences of ADA (8%) and NAbs (4.0%) were reported in patients on RMP. Overall, the efficacy, safety, immunogenicity, and pharmacokinetic parameters of DRL_BZ and RMP were found to be comparable. Clinical Trial Registration For BZ-01-002: CTRI/2016/01/006481.

Safety outcomes when switching between biosimilars and reference biologics: A systematic review and meta-analysis.

Biosimilars are increasingly available for the treatment of many serious disorders, however some concerns persist about switching a patient to a biosimilar whose condition is stable while on the reference biologic. Randomized controlled studies and extension studies with a switch treatment period (STP) to or from a biosimilar and its reference biologic were identified from publicly available information maintained by the U.S. Food and Drug Administration (FDA). These findings were augmented with data from peer reviewed publications containing information not captured in FDA reviews. Forty-four STPs were identified from 31 unique studies for 21 different biosimilars. Data were extracted and synthesized following PRISMA guidelines. Meta-analysis was conducted to estimate the overall risk difference across studies. A total of 5,252 patients who were switched to or from a biosimilar and its reference biologic were identified. Safety data including deaths, serious adverse events, and treatment discontinuation showed an overall risk difference (95% CI) of -0.00 (-0.00, 0.00), 0.00 (-0.01, 0.01), -0.00 (-0.01, 0.00) across STPs, respectively. Immunogenicity data showed similar incidence of anti-drug antibodies and neutralizing antibodies in patients within a STP who were switched to or from a biosimilar to its reference biologic and patients who were not switched. Immune related adverse events such as anaphylaxis, hypersensitivity reactions, and injections site reactions were similar in switched and non-switched patients. This first systematic review using statistical methods to address the risk of switching patients between reference biologics and biosimilars finds no difference in the safety profiles or immunogenicity rates in patients who were switched and those who remained on a reference biologic or a biosimilar.

Immunogenicity of Cemiplimab: Low Incidence of Antidrug Antibodies and Cut-Point Suitability Across Tumor Types.

The immunogenicity of cemiplimab, a fully human immunoglobulin G4 monoclonal antibody directed against programmed cell death1, was assessed in patients across multiple tumor types. The development of antidrug antibodies (ADAs) against cemiplimab was monitored using a validated bridging immunoassay. To identify ADA-positive samples in the assay, statistically determined cut points were established by analyzing baseline clinical study samples from a mixed population of different tumor types, and this validation cut point was used to assess immunogenicity in all subsequent studies. Regulatory guidance requires that ADA assay cut points be verified for appropriateness in different patient populations. Thus, for the cemiplimab ADA assay, we evaluated whether each new oncology population was comparable with the validation population used to set the cut point. Assay responses from 2393 individual serum samples from 8 different tumor types were compared with the validation population, using established statistical methods for cut-point determination and comparison, with no significant differences observed. Across tumor types, the immunogenicity of cemiplimab was low, with an overall treatment-emergent ADA incidence rate of 1.9% and 2.5% at intravenous dose regimens of 3mg/kg every 2weeks and 350mg every 3weeks, respectively. Moreover, no neutralizing antibodies to cemiplimab were detected in patients with ADA-positive samples, and there was no observed impact of cemiplimab ADAs on pharmacokinetics. Study-specific cut points may be required in some diseases, such as immune and inflammatory diseases; however, based on this analysis, in-study cut points are not required for each new oncology disease indication for cemiplimab.

Anti-drug antibodies related to CTLA-4, PD-1, or PD-L1 inhibitors across tumour types: A systematic review.

e14600 Background: Treatment-emergent anti-drug antibodies (ADAs) are postulated to reduce the efficacy of immune checkpoint inhibitors. A systematic review (SR) was conducted to evaluate the incidence of treatment-emergent ADAs with programmed cell death protein 1 (PD-1)/programmed death-ligand 1 (PD-L1), or cytotoxic T-lymphocyte-associated protein 4 (CTLA-4) inhibitors and their impact on treatment outcomes in patients with cancer. Methods: Electronic databases MEDLINE, EMBASE and Cochrane Library were searched in February 2022 for studies reporting incidence of ADAs and the impact of immunogenicity on treatment efficacy in oncology patients treated with PD-1, PD-L1, or CTLA-4 checkpoint inhibitors. Results: Of the 4,612 articles identified, 34 publications reporting on 68 trials were included. An additional 41 and 32 records were identified from clinicaltrials.gov and packaging inserts respectively. In total, 141 trials of 15 checkpoint inhibitors and 16 tumour types were included. There was considerable variability in the reporting of ADAs, and comparisons between trials were challenging due to intra-study heterogeneity. The incidence of ADAs ranged from 0 to 74%. Across trials, in analyses with the largest sample sizes, atezolizumab was associated with the highest incidence of ADAs (29.6%), then nivolumab (12.2%), followed by the remaining treatments (0-4.4%). The incidence of neutralising antibodies (nAbs) mirrored ADA distribution, being highest for atezolizumab (4.3–27.5%) vs other treatments. Only 17 trials reported on ADA impact on treatment outcomes. Of 11 trials examining efficacy, two reported a negative effect of ADAs, eight reported no measurable effect and another had insufficient patient numbers. The impact of ADAs on treatment safety, and pharmacokinetics was also inconclusive. Conclusions: Treatment-emerging ADAs are inconsistently reported across trials and documented in up to 30% of subjects treated with checkpoint inhibitors across indications. Emergence of nAbs follows but does not perfectly mirror ADA titers, raising questions around the functional meaning of different ADAs. Standardised reporting of ADAs and nAbs should be advocated to facilitate more conclusive immunologic and clinical insight as to the relationship with ADAs and response. [Table: see text]