A root cause analysis to identify the mechanistic drivers of immunogenicity against the anti-VEGF biotherapeutic brolucizumab

KESTREL and KITE Phase 3 Studies: 100-Week Results With Brolucizumab in Patients With Diabetic Macular Edema

PURPOSE

To report the 100-week outcomes from the KESTREL and KITE trials.

DESIGN

Two phase 3, double-masked, active-controlled, randomized trials.

METHODS

Patients with diabetic macular edema (DME) were randomized 1:1:1 to brolucizumab 3 mg/6 mg (BRO3/BRO6) or aflibercept 2 mg (AFL) in KESTREL (N = 566) or 1:1 to BRO6 or AFL in KITE (N = 360). BRO3/BRO6 arms received 5 loading doses every 6 weeks (q6w) followed by q12w dosing, with an option to adjust to q8w at predefined disease activity assessment visits. In KITE, at week 72, based on the disease stability assessment, treatment intervals could be extended by 4 weeks in the BRO6 arm. AFL arms received 5 monthly loading doses followed by fixed q8w dosing.

RESULTS

At week 100, change from baseline in BCVA (letters) was +8.8 for BRO6 and +10.6 for AFL in KESTREL; and +10.9 for BRO6 and +8.4 for AFL in KITE. In both studies, fewer BRO6 subjects had intraretinal fluid and/or subretinal fluid than AFL subjects. Results were achieved with 32.9% (KESTREL) and 47.5% (KITE) of BRO6 subjects maintained on q12w and q12w/q16w dosing, respectively. Intraocular inflammation rates for BRO6 vs AFL were 4.2% vs 1.1% (KESTREL) and 2.2% vs 1.7% (KITE), of which retinal vasculitis rates were 0.5% vs 0% in KESTREL, with no cases in KITE. Retinal vascular occlusion rates were 1.6% vs 0.5% (KESTREL) and 0.6% in both treatment arms in KITE.

CONCLUSIONS

Results show the long-term efficacy and durability of brolucizumab in improving visual and anatomical outcomes in DME; the overall safety profile of brolucizumab remained unchanged through year 2.

INCIDENCE AND RISK FACTORS OF INTRAOCULAR INFLAMMATION AFTER BROLUCIZUMAB TREATMENT IN JAPAN: A Multicenter Age-Related Macular Degeneration Study

PURPOSE

To investigate the incidence of intraocular inflammation (IOI) and its risk factors following intravitreal injections of brolucizumab for neovascular age-related macular degeneration in Japan.

METHODS

A total of 1,351 Japanese consecutive patients with neovascular age-related macular degeneration who were treated with brolucizumab from May 2020 to May 2022 at 14 institutions were examined. The variables analyzed were the number of brolucizumab injections, time to onset of IOI, and risk factors.

RESULTS

Intraocular inflammation developed in 152 eyes (11.3%). Retinal vasculitis and/or retinal occlusion occurred in 53 eyes (3.9%). Ninety-four patients received bilaterally, bilateral IOI occurred in five patients (5.3%). Sixteen eyes (1.2%) had irreversible visual acuity loss and nine eyes (0.67%) had visual loss of three lines or more due to retinal vasculitis and/or retinal occlusion. The cumulative IOI incidence was 4.5%, 10.3%, and 12.2% at 30, 180, and 365 days (1-year), respectively. History of IOI (including retinal vasculitis) and/or retinal occlusion (odds ratio [OR], 5.41; P = 0.0075) and female sex (OR, 1.99; P = 0.0004) were significantly associated with IOI onset.

CONCLUSION

The 1-year cumulative incidence of IOI in Japanese neovascular age-related macular degeneration patients treated with brolucizumab was 12.2%. History of IOI (including retinal vasculitis) and/or retinal occlusion and female sex were significant risk factors.

Immunogenicity and Potential for Intraocular Inflammation of Intravitreal Anti-VEGF Drugs

Background

Concerns of intraocular inflammation associated with intravitreal administration of anti-VEGF drugs have been risen and the exact mechanism is not yet elucidated.

Objective

To explore the relationship between immunogenicity and intraocular inflammation in intravitreal anti-VEGF drugs.

Methods

This review examines the immunogenicity of individual intravitreal anti-VEGF drugs and their potential link to intraocular inflammation.

Results

We suggest that the main cause of intraocular inflammation is the presence of pre-existing and treatment-induced antidrug antibodies, along with considerations related to the molecular structure, which includes the drug's format and size.

Conclusions

Researchers and clinicians involved in the advancement of new anti-VEGF drugs should take into consideration the factors related to intraocular inflammation that have been discussed.

Reducing Immunogenicity by Design: Approaches to Minimize Immunogenicity of Monoclonal Antibodies

Monoclonal antibodies (mAbs) have transformed therapeutic strategies for various diseases. Their high specificity to target antigens makes them ideal therapeutic agents for certain diseases. However, a challenge to their application in clinical practice is their potential risk to induce unwanted immune response, termed immunogenicity. This challenge drives the continued efforts to deimmunize these protein therapeutics while maintaining their pharmacokinetic properties and therapeutic efficacy. Because mAbs hold a central position in therapeutic strategies against an array of diseases, the importance of conducting comprehensive immunogenicity risk assessment during the drug development process cannot be overstated. Such assessment necessitates the employment of in silico, in vitro, and in vivo strategies to evaluate the immunogenicity risk of mAbs. Understanding the intricacies of the mechanisms that drive mAb immunogenicity is crucial to improving their therapeutic efficacy and safety and developing the most effective strategies to determine and mitigate their immunogenic risk. This review highlights recent advances in immunogenicity prediction strategies, with a focus on protein engineering strategies used throughout development to reduce immunogenicity.

Factors Associated With Intraocular Inflammation in Neovascular Age-Related Macular Degeneration Patients Treated With Brolucizumab

Purpose

To identify factors associated with intraocular inflammation (IOI) in patients with neovascular age-related macular degeneration (nAMD) treated with brolucizumab.

Methods

In this prospective observational study, we collected aqueous humor samples from 96 eyes of 96 patients receiving treatment with brolucizumab; IOI subsequently developed in 19 eyes of 19 patients. To identify cytokines upregulated in eyes with subsequent development of IOI, we compared the aqueous humor cytokine levels between the IOI and non-IOI groups. We also collected plasma from 20 patients who developed IOI and 20 age- and sex-matched controls to identify differences in plasma biomarkers and the subfraction of CD4+ cells. Using stepwise variable selection and multivariate binary regression analysis, we developed an algorithm that accurately assessed the likelihood of IOI occurrence.

Results

The IOI group showed elevated aqueous humor levels of P-selectin (584 vs. 324 pg/mL, P = 0.013), TNF-α (0.89 vs. 0.60 pg/mL, P = 0.018), and IL-1α (2.0 vs. 1.4 pg/mL, P = 0.035) compared with the non-IOI group. Serum MMP-9 concentrations were higher in the IOI group than the non-IOI group (18,310 vs. 13,450 pg/mL, P = 0.029). Furthermore, the percentage of Th2 cells was significantly decreased in the IOI compared with the non-IOI group (3.1% vs. 4.2%, P = 0.013). The receiver operating characteristic curves for the optimal models showed an area under the curve ranging from 0.71 to 0.89, indicating good performance.

Conclusions

The combination of elevated concentrations of multiple aqueous humor cytokines and of serum MMP-9 and a lower number of plasma Th2 cells is associated with brolucizumab-related IOI in patients with nAMD.

Gains in the current understanding of managing neovascular AMD with brolucizumab

BACKGROUND

Unresolved retinal fluid and high injection burden are major challenges for patients with neovascular age-related macular degeneration. Brolucizumab addresses these challenges by providing robust vision gains and superior fluid resolution, with the potential for longer treatment intervals. Brolucizumab has been associated with adverse events of retinal vasculitis and retinal vascular occlusion typically in the presence of intraocular inflammation (IOI). To define the incidence of the adverse events, Novartis convened an external safety review committee, which found a rate of 4.6% for definite or probable IOI, 3.3% for retinal vasculitis, and 2.1% for retinal vascular occlusion in the HAWK and HARRIER trials. Novartis also established a coalition to explore 4 areas regarding the adverse events: root cause, patient characterization, event mitigation and vigilance, and treatment protocols for the adverse events. Based on the coalition findings, a risk mitigation framework was developed. Prior to initiating treatment with brolucizumab, it is important to weigh the potential benefit against risk of adverse events and to consider patient risk factors such as prior history of IOI and/or retinal vascular occlusion. To mitigate the potential for IOI-related adverse events, it is important to conduct a thorough dilated eye examination before each injection and closely monitor patients throughout treatment. Patients should be educated on symptoms of IOI to monitor for. Brolucizumab should not be injected in the presence of active IOI. If an adverse event is identified, prompt and intensive treatment should be considered.

CONCLUSION

Progress has been made in understanding how to mitigate IOI-related adverse events following treatment with brolucizumab.

Characterization and root cause analysis of immunogenicity to pasotuxizumab (AMG 212), a prostate-specific membrane antigen-targeting bispecific T-cell engager therapy

Introduction

In oncology, anti-drug antibody (ADA) development that significantly curtails response durability has not historically risen to a level of concern. The relevance and attention ascribed to ADAs in oncology clinical studies have therefore been limited, and the extant literature on this subject scarce. In recent years, T cell engagers have gained preeminence within the prolific field of cancer immunotherapy. These drugs whose mode of action is expected to potently stimulate anti-tumor immunity, may potentially induce ADAs as an unintended corollary due to an overall augmentation of the immune response. ADA formation is therefore emerging as an important determinant in the successful clinical development of such biologics.

Methods

Here we describe the immunogenicity and its impact observed to pasotuxizumab (AMG 212), a prostate-specific membrane antigen (PSMA)-targeting bispecific T cell engager (BiTE®) molecule in NCT01723475, a first-in-human (FIH), multicenter, dose-escalation study in patients with metastatic castration-resistant prostate cancer (mCRPC). To explain the disparity in ADA incidence observed between the SC and CIV arms of the study, we interrogated other patient and product-specific factors that may have explained the difference beyond the route of administration.

Results

Treatment-emergent ADAs (TE-ADA) developed in all subjects treated with at least 1 cycle of AMG 212 in the subcutaneous (SC) arm. These ADAs were neutralizing and resulted in profound exposure loss that was associated with contemporaneous reversal of initial Prostate Surface Antigen (PSA) responses, curtailing durability of PSA response in patients. Pivoting from SC to a continuous intravenous (CIV) administration route remarkably yielded no subjects developing ADA to AMG 212. Through a series of stepwise functional assays, our investigation revealed that alongside a more historically immunogenic route of administration, non-tolerant T cell epitopes within the AMG 212 amino acid sequence were likely driving the high-titer, sustained ADA response observed in the SC arm.

Discussion

These mechanistic insights into the AMG 212 ADA response underscore the importance of performing preclinical immunogenicity risk evaluation as well as advocate for continuous iteration to better our biologics.

Detection and Management of Intraocular Inflammation after Brolucizumab Treatment for Neovascular Age-Related Macular Degeneration

PURPOSE

To present interim descriptive insights from the OCTOPUS and SWIFT studies on incidence, clinical features, management, and outcomes of intraocular inflammation (IOI), vasculitis, and occlusive vasculitis with brolucizumab treatment (Beovu, Novartis) in patients with neovascular age-related macular degeneration (nAMD) who were anti-VEGF naive or pretreated with anti-VEGFs (ranibizumab or aflibercept).

DESIGN

OCTOPUS (NCT04239027) and SWIFT (NCT04264819) studies are prospective phase IIIb single-arm, open-label, multicenter studies assessing brolucizumab.

SUBJECTS

Anti-VEGF naive (OCTOPUS) and pretreated (SWIFT) patients with nAMD.

METHODS

Interim prespecified analysis on the efficacy end point provided an opportunity to analyze IOI-related safety. Reports of IOI-related adverse events (AEs) were reviewed, and AE images and clinical features and outcomes of each case were analyzed by a review committee.

RESULTS

Of 505 brolucizumab-treated eyes/patients with median brolucizumab treatment of 8.8 months, 53 eyes demonstrated at least 1 IOI-related AE. The incidence of overall IOI-related AEs was 10.5%; among these events, the incidence was 7.1% for IOI only without retinal involvement and 3.4% for IOI with retinal involvement (2.0% with vasculitis, 1.4% with vascular occlusion with or without vasculitis). Incidence was similar in naive and pretreated patients. Before the onset of the first IOI-related AE, eyes received a median of 2 brolucizumab injections; 81.1% of IOI-related AEs occurred during the loading phase (median, 25.0 days from the last brolucizumab injection). At AE onset, most frequently reported symptoms were floaters (52.8%) and blurred or decreased vision (37.8%). Of the 86.8% of AEs that were treated, most were treated with topical corticosteroids (75.5%), 28.3% by systemic corticosteroids, and 26.8% by intraocular corticosteroids. No severe vision loss was reported for the 7 nontreated AEs. Overall, the median best-corrected visual acuity (BCVA) change at IOI-related AEs resolution from baseline was 1 letter (range, -74 to +32 letters), and 2 patients with occlusive vasculitis had BCVA loss ≥ 15 letters due to IOI-related AEs. All eyes permanently discontinued brolucizumab after the first IOI-related AE.

CONCLUSIONS

This analysis highlights the need for monitoring and education of patients to report any signs of IOI-related events immediately when being treated with brolucizumab. IOI should be treated promptly and intensely with corticosteroids.

FINANCIAL DISCLOSURE(S)

Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.

2022 White Paper on Recent Issues in Bioanalysis: FDA Draft Guidance on Immunogenicity Information in Prescription Drug Labeling, LNP & Viral Vectors Therapeutics/Vaccines Immunogenicity, Prolongation Effect, ADA Affinity, Risk-based Approaches, NGS, qPCR, ddPCR Assays (Part 3 - Recommendations on Gene Therapy, Cell Therapy, Vaccines Immunogenicity & Technologies; Immunogenicity & Risk Assessment of Biotherapeutics and Novel Modalities; NAb Assays Integrated Approach)

The 2022 16th Workshop on Recent Issues in Bioanalysis (WRIB) took place in Atlanta, GA, USA on September 26-30, 2022. Over 1000 professionals representing pharma/biotech companies, CROs, and multiple regulatory agencies convened to actively discuss the most current topics of interest in bioanalysis. The 16th WRIB included 3 Main Workshops and 7 Specialized Workshops that together spanned 1 week in order to allow exhaustive and thorough coverage of all major issues in bioanalysis, biomarkers, immunogenicity, gene therapy, cell therapy and vaccines. Moreover, in-depth workshops on ICH M10 BMV final guideline (focused on this guideline training, interpretation, adoption and transition); mass spectrometry innovation (focused on novel technologies, novel modalities, and novel challenges); and flow cytometry bioanalysis (rising of the 3rd most common/important technology in bioanalytical labs) were the special features of the 16th edition. As in previous years, WRIB continued to gather a wide diversity of international, industry opinion leaders and regulatory authority experts working on both small and large molecules as well as gene, cell therapies and vaccines to facilitate sharing and discussions focused on improving quality, increasing regulatory compliance, and achieving scientific excellence on bioanalytical issues. This 2022 White Paper encompasses recommendations emerging from the extensive discussions held during the workshop and is aimed to provide the bioanalytical community with key information and practical solutions on topics and issues addressed, in an effort to enable advances in scientific excellence, improved quality and better regulatory compliance. Due to its length, the 2022 edition of this comprehensive White Paper has been divided into three parts for editorial reasons. This publication (Part 3) covers the recommendations on Gene Therapy, Cell therapy, Vaccines and Biotherapeutics Immunogenicity. Part 1 (Mass Spectrometry and ICH M10) and Part 2 (LBA, Biomarkers/CDx and Cytometry) are published in volume 15 of Bioanalysis, issues 16 and 15 (2023), respectively.

Layer-by-Layer Microneedle-Mediated rhEGF Transdermal Delivery for Enhanced Wound Epidermal Regeneration and Angiogenesis

Appropriate treatments for acute traumas tend to avoid hemorrhages, vascular damage, and infections. However, in the homeostasis-imbalanced wound microenvironment, currently developed therapies could not precisely and controllably deliver biomacromolecular drugs, which are confronted with challenges due to large molecular weight, poor biomembrane permeability, low dosage, rapid degradation, and bioactivity loss. To conquer this, we construct a simple and effective layer-by-layer (LBL) self-assembly transdermal delivery patch, bearing microneedles (MN) coated with recombinant human epidermal growth factor (LBL MN-rhEGF) for a sustained release to wound bed driven by typical electrostatic force. Pyramidal LBL MN-rhEGF patches hold so enough mechanical strength to penetrate the stratum corneum, and generated microchannels allow rhEGF direct delivery in situ. The administrable delivery of biomacromolecular rhEGF through hierarchically coated MN arrays follows the diffusion mechanism of Fick's second law. Numerous efforts further have illustrated that finger-pressing LBL MN-rhEGF patches could not only promote cell proliferation of normal human dermal fibroblasts (NHDF) and human umbilical vein endothelial cells (HUVEC) in vitro but also take significant effects (regenerative epidermis: ∼144 μm; pro-angiogenesis: higher CD31 expression) in accelerating wound healing of mechanically injured rats, compared to the traditional dressing, which relies on passive diffusion. Our proof-of-concept features novel LBL biomacromolecular drug-delivery systems and self-administrated precision medicine modes at the point of care.

Anti-brolucizumab immune response as one prerequisite for rare retinal vasculitis/retinal vascular occlusion adverse events

In October 2019, Novartis launched brolucizumab, a single-chain variable fragment molecule targeting vascular endothelial growth factor A, for the treatment of neovascular age-related macular degeneration. In 2020, rare cases of retinal vasculitis and/or retinal vascular occlusion (RV/RO) were reported, often during the first few months after treatment initiation, consistent with a possible immunologic pathobiology. This finding was inconsistent with preclinical studies in cynomolgus monkeys that demonstrated no drug-related intraocular inflammation, or RV/RO, despite the presence of preexisting and treatment-emergent antidrug antibodies (ADAs) in some animals. In this study, the immune response against brolucizumab in humans was assessed using samples from clinical trials and clinical practice. In the brolucizumab-naïve population, anti-brolucizumab ADA responses were detected before any treatment, which was supported by the finding that healthy donors can harbor brolucizumab-specific B cells. This suggested prior exposure of the immune system to proteins with structural similarity. Experiments on samples showed that naïve and brolucizumab-treated ADA-positive patients developed a class-switched, high-affinity immune response, with several linear epitopes being recognized by ADAs. Only patients with RV/RO showed a meaningful T cell response upon recall with brolucizumab. Further studies in cynomolgus monkeys preimmunized against brolucizumab with adjuvant followed by intravitreal brolucizumab challenge demonstrated that high ADA titers were required to generate ocular inflammation and vasculitis/vascular thrombosis, comparable to RV/RO in humans. Immunogenicity therefore seems to be a prerequisite to develop RV/RO. However, because only 2.1% of patients with ADA develop RV/RO, additional factors must play a role in the development of RV/RO.