BioProcess International Peptide SPECIAL REPORT Therapeutics Designing a Science-Led Strategic Quality Control Program INTERTEK PHARMACEUTICAL SERVICES Your partner for regulatory-driven, phase appropriate analytical programs tailored to your molecule. Our experts help you to navigate the challenges of development, regulatory submission, and manufacturing. Peptide Therapeutics Designing a Science-Led Strategic Quality Control Program Shashank Sharma and Hannah Lee ince the emergence of peptide therapeutics in the 1920s with the advent of insulin therapy, the market for this product class has continued to expand with global revenues anticipatedS to surpass US$50 billion by 2024 (1). The growth of peptide therapeutics is attributed not only to improvements in manufacturing, but also to a rise in demand because of an increasingly aging population that is driving an increase in the occurrence of long-term diseases. The need for efficient and low-cost drugs and rising investments in research and development of novel drugs continues to boost market growth and fuel the emergence of generic versions that offer patients access to vital medicines at low costs. North America has been the dominant market for peptide therapeutics, with the Asia–Pacific region Insulin molecular model; the first therapeutic expected to grow at a faster rate. The global peptides use of this peptide hormone was in the market has attracted the attention of key players 1920s to treat diabetic patients. within the pharmaceutical industry, including Teva Pharmaceuticals, Eli Lilly, Novo Nordisk, Pfizer, amino acids to be peptides. Within that set, those Takeda, and Amgen. Those companies have made containing 10 or more are classed as polypeptides. available several highly successful blockbuster There is some ambiguity here. For example, insulin, peptide drugs, including glatiramer acetate, one of the most common peptide therapeutics, is liraglutide, and leuprorelin. Currently, more than 100 classed as a peptide hormone, but it contains 51 approved peptide therapeutics are commercially amino acids. Peptides are a unique category of available for multiple clinical indications such as biopharmaceutical compound. Playing on the cancer (projected to be the fastest growing segment), strengths of both small molecules and protein cardiovascular disease, central nervous system and therapeutics, they combine the size of small metabolic disorders, infectious disease, acromegaly, molecules and their ability to penetrate cell and hematological, gastrointestinal, and respiratory membranes with a protein’s high specificity for its disorders. The development pipeline is robust with target. This enables peptides to interfere with more than 100 peptides in late-stage clinical protein–protein interactions (PPIs) and target or development and more than 200 in preclinical stages inhibit intracellular molecules. Small molecules (1). Within that pipeline, 21 peptides are being struggle with larger binding sites, whereas proteins assessed to address the recent global outbreak of and antibodies cannot cross over the cell membrane COVID-19 (2) (see “Peptides” box). to reach such target sites. Although peptides occur naturally in the body Therapeutic Advantages of Peptides and throughout nature, they are unique in how they The US Food and Drug Administration (FDA) are manufactured for therapeutic benefit. They can considers all biopolymers composed of 40 or fewer be produced synthetically in a laboratory (e.g., 2 BioProcess International 18(9)si September 2020 SPONSORED Table 1: Analytical methods to determine critical quality attributes (CQAs) for peptide therapeutics Attribute Characteristics Analytical Methods1 Comparative Primary sequence confirmation Peptide mapping approach (LC-MS/MS) covering full sequence physiochemical and confirmation, posttranslational modifications information (if applicable) structural and confirmation of disulfide (if peptide contacts cysteine) characterization N-terminal sequence Edman degradation Amino acid composition Amino acid analyzer Intact mass analysis MALDI ToF/LCMS/ESI MS Secondary structure profiling CD (near, far, and thermal denaturation), FTIR, DSC, XRD High-order structure NMR 1D (hydrogen-1 and carbon-13), 2D (TOCSY and NOESY) Optical purity GCMS Chiral confirmation GCMS/LCMS Impurity profiling Oligomer/aggregation UV-SEC-MALS, SV-AUC, DLS, SDS-PAGE, CE SDS Charge variant profiling iCIEF/IEX Peptide-related impurity profiling UPLC/HPLC-HR-MS/MS, RP-HPLC Biological comparability Cell-based assay/immunoassay Using specific cell line or kits Bioidentity test As per monograph, if available 1 LC = liquid chromatography, MS = mass spectroscopy, MALDI = matrix-assisted laser desorption/ionization, ToF = time of flight, ESI = electrospray ionization, CD = circular dichroism, FTIR = Fourier-transform infrared, DSC = differential scanning calorimeter, XRD = x-ray diffraction, NMR = nuclear magnetic resonance, 1D = one dimensional, 2D = two dimensional, TOCSY = total correlation spectroscopy, NOESY = nuclear Overhauser effect spectroscopy, GC = gas chromatography, UV = ultraviolet, SEC = size-exclusion chromatography, MALS = multiangle light scattering, SV-AUC = sedimentation velocity analytical ultracentrifugation, DLS = dynamic light scattering, SDS = sodium dodecyl sulfate, PAGE = polyacrylamide gel electrophoresis, CE = capillary electrophoresis, iCIEF = imaged capillary isoelectric focusing, IEX = ion-exchange chromatography, UPLC = ultraperformance liquid chromatography, HPLC = high-performance liquid chromatography, HR = high resolution, RP = reversed phase oxytocin) but also can be produced using bacteria guidelines for peptide therapeutics. Depending on and other living organisms as well as recombinant their length, intended clinical indication, and DNA technology (e.g., insulin). That gives peptides manufacturing technology, peptides can be regarded another dynamic advantage over their protein and as conventional chemical molecules or as biological small-molecule counterparts. In recent years, entities or biosimilars. Regulatory guidance is peptides of smaller size with optimum balance of outlined by the International Council for conformational rigidity and flexibility have become Harmonisation of Technical Requirements for promising candidates for targeting challenging Pharmaceuticals for Human Use (ICH) for small- binding interfaces with satisfactory binding affinity molecule drugs and their impurities (3). Regulatory and specificity. guidance for biologicals also is available, and guidance for biosimilars is being developed. Regulatory Expectations and Challenges Currently, however, the industry lacks guidelines for The FDA regulates peptides under the Food, Drug, the regulation of peptide drugs, resulting in a and Cosmetic (FD&C) Act, whereas a protein is regulatory vacuum. That presents a challenge to regulated under the Public Health Service Act. With peptide manufacturers. many peptide drugs already on the market, the main As per the FDA mandate, peptide products that regulatory challenge is to establish quality control have fewer than 10 amino acids and are made parameters of active pharmaceutical ingredients through chemical synthesis fall into the jurisdiction (APIs) and/or drug substances before manufacturing of new drug approval (NDA) pathways; those made finished drug products. When developing a quality through recombinant DNA (rDNA) technologies must control (QC) strategy, several tests — including those go through the biologics license application (BLA) to evaluate impurities and high–molecular-weight process. A product approved as an abbreviated NDA impurities as well as amino-acid analysis (AAA), (ANDA) is considered to be a generic and moisture determination, and microbiological testing interchangeable with its reference product (4). — should be considered when setting specifications However, a product approved through biosimilar to evaluate the final quality of a product before its pathways will need to demonstrate interchangeability release. because of the differences in manufacturing An additional challenge within the regulatory technologies between biosimilar peptides and those of landscape is the limited availability of specific reference products. During drug development, SPONSORED September 2020 18(9)si BioProcess International 3 Peptides: A Potential Therapeutic Against COVID-19 The unprecedented impact of COVID-19 is accelerating the for cell entry offer a potential treatment option by blocking development of next-generation vaccines and therapies key regions of the spike protein, disabling the virus, and around the world to help prevent infection and to aid patient preventing infection in human cells. As intrinsic signaling recovery. The range of COVID-19 therapy and vaccine molecules for many physiological functions, peptides technology platforms is broad, with products based on present an opportunity for therapeutic intervention to disrupt nucleic acid (DNA and RNA), antibodies, small molecules protein–protein interactions (PPIs) and target or inhibit and peptides, virus-like particles, and live–attenuated or intracellular molecules such as receptor tyrosine kinases. inactivated viruses. According to GlobalData’s Pharma Because peptides generally offer greater efficacy, safety, Intelligence Center Pipeline Drugs Database, 21 peptide and tolerability in humans than do small molecules, and they drugs are in development to target COVID-19, including 15 can penetrate cell membranes because of their smaller size