Immunogenicity risk assessment of synthetic peptide drugs and their impurities

Analytical considerations for characterization of generic peptide product: A regulatory insight

The Peptide therapeutics market was evaluated to be around USD 45.67 BN in 2023 and is projected to witness massive growth at a CAGR of around 5.63 % from 2024 to 2032 (USD 80.4 BN). Generic peptides are expected to reach USD 27.1 billion by 2032 after the patent monopoly of the pioneer peptides expires, and generic peptides become accessible. The generic manufacturers are venturing into peptide-based therapeutics for the aforementioned reasons. There is an abundance of material accessible regarding the characterization of peptides, which can be quite confusing for researchers. The FDA believes that an ANDA applicant may now demonstrate that the active component in a proposed generic synthetic peptide drug product is the "same" as the active ingredient in a peptide of rDNA origin that has previously been approved. To ensure the efficacy, safety, and quality of peptide therapies during development, regulatory bodies demand comprehensive characterization utilizing several orthogonal methodologies. This article elaborates the peptide characterization by segmenting into different segments as per the critical quality attribute from identification of the peptide to the physicochemical property of the peptide therapeutics which will be required to demonstrate the sameness with reference product based on the size of the peptide chain and molecular weight of the peptides. Article insights briefly on each individual technique and the orthogonal techniques for each test were explained. The impurities requirements in the generic peptides as per the regulatory requirement were also discussed.

Proteolysis-targeting drug delivery system (ProDDS): integrating targeted protein degradation concepts into formulation design

Targeted protein degradation (TPD) has emerged as a revolutionary paradigm in drug discovery and development, offering a promising avenue to tackle challenging therapeutic targets. Unlike traditional drug discovery approaches that focus on inhibiting protein function, TPD aims to eliminate proteins of interest (POIs) using modular chimeric structures. This is achieved through the utilization of proteolysis-targeting chimeras (PROTACs), which redirect POIs to E3 ubiquitin ligases, rendering them for degradation by the cellular ubiquitin-proteasome system (UPS). Additionally, other TPD technologies such as lysosome-targeting chimeras (LYTACs) and autophagy-based protein degraders facilitate the transportation of proteins to  endo-lysosomal or autophagy-lysosomal pathways for degradation, respectively. Despite significant growth in preclinical TPD research, many chimeras fail to progress beyond this stage in the drug development. Various factors contribute to the limited success of TPD agents, including a significant hurdle of inadequate delivery to the target site. Integrating TPD into delivery platforms could surmount the challenges of in vivo applications of TPD strategies by reshaping their pharmacokinetics and pharmacodynamic profiles. These proteolysis-targeting drug delivery systems (ProDDSs) exhibit superior delivery performance, enhanced targetability, and reduced off-tissue side effects. In this review, we will survey the latest progress in TPD-inspired drug delivery systems, highlight the importance of introducing delivery ideas or technologies to the development of protein degraders, outline design principles of protein degrader-inspired delivery systems, discuss the current challenges, and provide an outlook on future opportunities in this field.

Development and validation of stability-indicating assay method and identification of force degradation products of glucagon-like peptide-1 synthetic analog Exenatide using liquid chromatography coupled with Orbitrap mass spectrometer

Exenatide is a synthetic glucagon-like peptide 1 analog, widely used in the management of type 2 diabetes mellitus. The stability of pharmaceutical products is significantly impacted by various environmental stress conditions. The present study reports the development of a validated reverse-phase high-performance liquid chromatography (RP-HPLC) stability-indicating method for the identification of force degradation products (DPs) of synthetic glucagon-like peptide-1 analog Exenatide using UHPLC-Orbitrap fusionTM mass spectrometer. Force degradation studies were performed by subjecting Exenatide to various stress conditions, such as hydrolytic, oxidative, photolytic and thermal to investigate the stability indicating ability of the method. Significant degradation was observed during acidic, oxidative, photolytic and thermal stress conditions. Exenatide and its major DPs identification and characterization were demonstrated by employing LC-HRMS and MS/MS method. In total, five major stress DPs were characterized, and their fragmentation pathway was proposed using MS/MS studies. Finally, the proposed RP-HPLC method was validated as per ICH guidance.

Tolerogenic Nano-/Microparticle Vaccines for Immunotherapy

Autoimmune diseases, allergies, transplant rejections, generation of antidrug antibodies, and chronic inflammatory diseases have impacted a large group of people across the globe. Conventional treatments and therapies often use systemic or broad immunosuppression with serious efficacy and safety issues. Tolerogenic vaccines represent a concept that has been extended from their traditional immune-modulating function to induction of antigen-specific tolerance through the generation of regulatory T cells. Without impairing immune homeostasis, tolerogenic vaccines dampen inflammation and induce tolerogenic regulation. However, achieving the desired potency of tolerogenic vaccines as preventive and therapeutic modalities calls for precise manipulation of the immune microenvironment and control over the tolerogenic responses against the autoantigens, allergens, and/or alloantigens. Engineered nano-/microparticles possess desirable design features that can bolster targeted immune regulation and enhance the induction of antigen-specific tolerance. Thus, particle-based tolerogenic vaccines hold great promise in clinical translation for future treatment of aforementioned immune disorders. In this review, we highlight the main strategies to employ particles as exciting tolerogenic vaccines, with a focus on the particles' role in facilitating the induction of antigen-specific tolerance. We describe the particle design features that facilitate their usage and discuss the challenges and opportunities for designing next-generation particle-based tolerogenic vaccines with robust efficacy to promote antigen-specific tolerance for immunotherapy.

Development of PD-1 blockade peptide-cell conjugates to enhance cellular therapies for T-cell acute lymphoblastic leukemia

Blockade of the interaction of the immune checkpoint receptor programmed cell death protein (PD)-1 and its ligand PD-L1 has been found to be a promising cancer treatment. Our previous studies identified that nABPD1 competed with PD-L1 to bind PD-1. The aim of this study was to evaluate the efficacy and safety of anti-tumor immunotherapy of ICIK cells conjugated with peptides in vivo and in vitro. Here, we synthesized the nABPD1 derivatives SBP1 and SBP2 and showed that their binding efficiency to PD-1-positive improving cytokine-induced killer (ICIK) cells was 98 and 82%, respectively. The cytotoxicity of ICIK cells to T-cell acute lymphoblastic leukemia (T-ALL) cells was increased by conjugating with SBP1 or SBP2, which was 2 times higher than that of ICIK cells alone. Furthermore, mice experiments showed that the fluorescence intensity of leukemia cells in T-ALL xenograft models was reduced by more than 95%, indicating that the peptides enhanced the therapeutic effect in vivo, while morphological evaluations showed that the peptides had no toxicity to important organs. Therefore, peptide-cell conjugates (PCCs) may be a novel method to improve the efficacy of cancer immunotherapy by blocking PD-1 in T-ALL patients.

Immunoinformatic Risk Assessment of Host Cell Proteins During Process Development for Biologic Therapeutics

The identification and removal of host cell proteins (HCPs) from biologic products is a critical step in drug development. Despite recent improvements to purification processes, biologics such as monoclonal antibodies, enzyme replacement therapies, and vaccines that are manufactured in a range of cell lines and purified using diverse processes may contain HCP impurities, making it necessary for developers to identify and quantify impurities during process development for each drug product. HCPs that contain sequences that are less conserved with human homologs may be more immunogenic than those that are more conserved. We have developed a computational tool, ISPRI-HCP, that estimates the immunogenic potential of HCP sequences by evaluating and quantifying T cell epitope density and relative conservation with similar T cell epitopes in the human proteome. Here we describe several case studies that support the use of this method for classifying candidate HCP impurities according to their immunogenicity risk.