Anti-Human IL-17RA (CD217) (Brodalumab) [Clone AMG-827]

Research-grade Brodalumab biosimilars are commonly used as calibration standards or reference controls in pharmacokinetic (PK) bridging ELISAs to accurately measure drug concentration in serum samples for biosimilar comparability studies.

To set up a PK bridging ELISA for Brodalumab:

• The biosimilar antibody (research-grade) is used to prepare a standard curve by spiking known concentrations of the antibody into serum samples that do not contain the drug. These standard curve points typically span the clinically relevant concentration range, such as 50 to 12,800 ng/mL.
• Quality Control (QC) samples are also prepared at various concentrations using the research-grade biosimilar to monitor assay performance and batch-to-batch reproducibility.
• Serum samples from study subjects are then tested in the same assay, and their Brodalumab concentrations are interpolated from the standard curve generated using the biosimilar standard. This ensures consistent quantification across both reference and test samples.

Key details include:

• Research-grade biosimilars are chosen due to their high purity (>95%), well-characterized isotype (e.g., human IgG2-Kappa), and lack of interfering stabilizers like BSA or azide, which improves reproducibility and accuracy in ELISA applications.
• Using a single analytical standard—often the biosimilar—for both reference and test products reduces variability and eliminates the need for cross-validation between standards, according to current industry best practices and regulatory guidance.
• Method validation includes comparing the biosimilar and reference product across multiple concentration ranges and runs to establish bioanalytical equivalence (usually within a predefined equivalence interval such as [0.8, 1.25]), which is essential for supporting biosimilar PK studies.

Summary of workflow:

• Use research-grade Brodalumab biosimilar as a reference standard.
• Generate standard curves and QC samples with it in human serum.
• Quantify clinical or preclinical serum samples by referencing this standard curve.
• Validate that biosimilar and reference standards yield equivalent results to confirm suitability for biosimilar assessment.

This approach ensures that the ELISA is robust, accurate, and suitable for comparing the PK profiles of Brodalumab biosimilars and innovator products in biosimilarity and bridging studies.

The primary models used to study the in vivo effects of anti-IL-17RA antibodies on tumor growth and tumor-infiltrating lymphocytes (TILs) are mouse syngeneic tumor models. These models typically use immune-competent mice implanted with mouse-derived tumor cell lines, allowing for a functional immune microenvironment in which TILs can be fully characterized after antibody intervention.

Key details from current studies include:

• Syngeneic mouse models: The MC38 colon adenocarcinoma model in C57BL/6 mice is a prominent example where an anti-IL-17RA antibody is administered, sometimes in combination with immune checkpoint inhibitors (e.g., anti-PD-1, anti-CTLA-4). This approach enables assessment of both tumor growth inhibition and immunological changes within TIL populations as a response to therapy.

• Immune cell analysis: In these systems, post-treatment tumors are processed to quantify and characterize the abundance and phenotypes of TILs through flow cytometry, immunohistochemistry, or transcriptomic profiling. The typical readouts include changes in regulatory T cells (Tregs), myeloid-derived suppressor cells (MDSCs), and effector T cells (e.g., CD8+ cytotoxic T lymphocytes).

• Genetic and cell-intrinsic models: Some studies use IL-17RA genetic knockout in tumor or host cells, supporting mechanistic understandings parallel to antibody blockade. For example, knockout or antibody blockade of IL-17RA in mouse models (such as transplantable osteosarcoma or genetically engineered colorectal cancer models) demonstrates tumor growth inhibition and alterations in TILs.

• Lack of humanized models in current literature: There is no direct evidence in the presented literature that fully humanized mouse models (i.e., human immune system reconstituted mice) have been used to study anti-IL-17RA antibodies for these purposes to date. Most published in vivo work employs mouse syngeneic or knockdown/knockout approaches.

Summary Table:

In summary:
Syngeneic mouse tumor models (especially MC38 and other commonly used mouse tumor lines) are the standard preclinical platforms where anti-IL-17RA antibodies are administered to study both tumor growth and TIL composition, as documented in recent literature. Genetic knockout models provide additional mechanistic insight, but studies in humanized mice are not described in the sources presented.

Researchers use Brodalumab biosimilars—which antagonize the interleukin-17 receptor A (IL-17RA)—in combination with other immune checkpoint inhibitors such as anti-CTLA-4 or anti-LAG-3 biosimilars to probe for synergistic or additive effects in complex immune-oncology models. This approach leverages the unique mechanisms of action of each antibody to dissect pathways that regulate immune responses in cancer.

Context and Experimental Strategy:

• Brodalumab biosimilars are monoclonal antibodies that block IL-17RA, thereby disrupting IL-17-mediated inflammation and immune cell recruitment, pathways relevant both to autoimmunity and tumor biology.
• Other checkpoint inhibitors (e.g., anti-CTLA-4, anti-LAG-3) target different inhibitory pathways—such as those dampening T cell activation or cytotoxicity within the tumor microenvironment—thus enhancing anti-tumor immunity by different mechanisms.

Research Use in Combinatorial Models:

• In preclinical and translational studies, researchers administer Brodalumab biosimilars and additional checkpoint inhibitors (e.g., anti-CTLA-4, anti-LAG-3) to tumor-bearing animal models or immune cell co-cultures. The goal is to:
  • Evaluate synergy in anti-tumor immune responses, e.g., improved T-cell activation, tumor regression, or decreased suppressive immune signals compared to single agents.
  • Study mechanistic crosstalk—for example, how IL-17 pathway blockade alters immune cell trafficking, overcoming tumor-mediated immunosuppression in conjunction with checkpoint inhibition.
  • Identify toxicities and immune-related adverse events unique to combination therapy, which are often more pronounced and must be understood for clinical translation.
• Data are frequently collected using flow cytometry, cytokine assays, immunohistochemistry, tumor growth measurement, and survival analyses to determine the magnitude and character of immune activation.

Clinical Research Considerations:

• Early clinical research is exploring Brodalumab’s role in managing side effects of checkpoint inhibitor immunotherapy rather than direct tumor targeting. However, the mechanistic rationale is pertinent to combination studies: modulating the balance between anti-tumor immunity and immune-related toxicity.
• Combination immune checkpoint blockade has already shown clinical synergy (not involving Brodalumab specifically) in melanoma and other cancers, supporting the translational value of these multi-pathway approaches.

Key Points:

• Combinations aim to harness non-overlapping mechanisms for robust tumor suppression.
• Synergy and safety are central experimental questions—efficacy must be balanced with risk of autoimmune complications.
• Brodalumab biosimilars offer reliable access to this pathway in research contexts, enabling systematic preclinical evaluation before advancing clinical development.

There are currently no published preclinical or clinical studies specifically illustrating Brodalumab biosimilar plus anti-CTLA-4/anti-LAG-3 in immune-oncology, but the methodology aligns closely with documented combinations of other checkpoint inhibitors and emerging checkpoint targeting strategies.

A Brodalumab biosimilar is used as a capture or detection reagent in a bridging ADA ELISA to monitor a patient’s immune response by specifically binding anti-Brodalumab antibodies (ADAs) that may develop in response to therapy. In a bridging ADA ELISA, both capture and detection reagents are typically the therapeutic drug (or its biosimilar) labeled differently; for example, one is biotinylated for capture and the other is conjugated to an enzyme (such as HRP) for detection.

Assay Principle and Workflow:

• Capture Step: The Brodalumab biosimilar, often biotinylated, is immobilized on a streptavidin-coated microplate or directly coated onto the wells. This forms the solid phase.
• Sample Incubation: Patient serum containing potential anti-Brodalumab antibodies (ADAs) is added. If present, ADAs bind to the immobilized Brodalumab biosimilar via one of their antigen-binding arms.
• Detection Step: An enzyme-conjugated (commonly HRP-labeled) Brodalumab biosimilar is then introduced. Because ADAs are bivalent, the remaining binding site of the ADA can bind this detection Brodalumab biosimilar, creating a “bridge” between the capture and detection reagents.
• Signal Development: After washing to remove non-specific components, a substrate (e.g., TMB for color development) is added and the signal is proportional to the amount of ADA in the sample, thus reflecting the patient's immune response to the drug.

Key Details:

• Using a biosimilar instead of the originator molecule as the reagent ensures assay availability, cost-effectiveness, and broader application without interfering with the proprietary therapeutic batch.
• The bridging format specifically detects bivalent antibodies (typically IgG) and is widely used because of its sensitivity, although free Brodalumab drug present in the serum may compete with reagents for ADA binding and reduce the assay’s sensitivity in samples with high drug concentrations.
• The FDA highlights that ELISA-based bridging ADA assays are a standard, semi-quantitative method for immunogenicity assessment in biosimilar development and post-approval monitoring.

Summary Table: Brodalumab Biosimilar in Bridging ADA ELISA

This method robustly detects and quantifies immune responses to Brodalumab therapy, providing essential data for clinical management and biosimilar development.