Reporting of quality attributes in scientific publications presenting biosimilarity assessments of (intended) biosimilars: a systematic literature review.

Last years, more than 46 unique biosimilars were approved by EMA and/or US-FDA following patent expiration of reference products. Biosimilars are not identical like generics, but highly similar versions where demonstrating biosimilarity of quality attributes (QAs) to a reference product is the basis of development and regulatory approval. Information on QAs assessed to establish biosimilarity may not always be publicly available, although this information is imperative to understand better the science behind biosimilars approval. This study aims to identify QA types reported in publications presenting biosimilarity assessments of (intended) biosimilars over time. English full-text publications presenting biosimilarity assessments of QAs for (intended) biosimilars between 2000 and 2019 identified from PubMed and EMBASE. Publication characteristics and QAs classified into: structural (physicochemical properties, primary structure, higher-order structures (HOSs), post-translational modifications (PTMs), and purity and impurities) and functional (biological and immunochemical activities) were extracted from publications. Seventy-nine publications were identified (79% open-access, 75% industry-sponsored, 62% including unapproved biosimilars, and 66% involving antibodies). Reporting frequencies varied for QA types: biological activity (94%), physicochemical properties (81%), PTMs (79%), primary structure (77%) purity and impurities (73%), HOSs (58%), and immunochemical activity (41%). The number of publications increased from 6 (7%) during 2009-2011 to 62 (79%) during 2015-2019. Eighteen (28%) publications reported all QA types relevant to an active-biological-substance. Reporting of most QA types increased over time that most evidenced by immunochemical activity (from 0% to 47%) which occured after EMA monoclonal antibody (mAbs) guidline in 2012 and more publications on mAbs later on when compared to earlier period. Biosimilarity assessments of QAs have been published in peer-reviewed publications for about 60% of approved biosimilars. Publishing biosimilarity assessments and reporting QAs over time appears to be affected by regulatory actions that occurred in 2012-2015, including regulatory approval and development of regulatory guidelines for biosimilars. Availability of a complete, publicly accessible and unbiased biosimilarity assessment of QAs, as part of a trusted and transparent regulatory process, will contribute to increased confidence and acceptance of biosimilars in clinical practice.

PDA Biosimilars Workshop Report (September 27-28, 2018)-Getting It Right the First Time for Biosimilar Marketing Applications.

This workshop report summarizes the presentations, the breakout session outcomes, and the speaker panel discussions from the PDA Biosimilars Workshop held September 27-28, 2018, in Washington, DC. This format was deliberately selected for the workshop with the expectation of delivering a post-workshop paper on current best practices and existing challenges for sponsors. The event, co-chaired by Dr. Stephan Krause (AstraZeneca Biologics) and Dr. Emanuela Lacana (CDER/FDA), was attended by 140 agency and industry representatives. The workshop was separated into three major sessions P1: Regulatory Perspective, P2: Challenges in Biosimilar Development, and P3: Demonstrating Analytical Similarity. Each of the three sessions started with agency and industry presentations. Participants then split into two concurrent roundtable discussion groups to hear the answers to questions that had been provided to all participants one week prior to the event. The sessions were recorded. This paper provides consolidated answers to specific case studies for current challenges to sponsors and agencies. In addition, the panel discussion notes following each breakout roundtable session, as well as brief talk summaries of all speakers, are provided. The first session explored the challenges encountered with submission of biosimilar marketing applications from the perspectives of regulatory agencies. Expectations for a successful submission of the chemistry, manufacturing, and controls (CMC) information were described. The second session addressed high-level technical challenges and how to avoid pitfalls frequently encountered during biosimilar candidate development, including data quality expectations, creation of the final control strategy, and strategic choices necessary for candidate selection and development. Both regulatory perspectives and industry experience were shared. The last session explored the use of statistical tools to provide meaningful contributions to the demonstration of analytical similarity. The presentations highlighted common issues and practical challenges that arise during the application of statistical tools.LAY ABSTRACT: Significant challenges are still-remaining for sponsors and agencies to successfully develop and license Biosimilars. A Biosimilars Workshop was therefore held on 27-28 September 2018 in Washington, DC, to find practical solutions to the remaining challenges. The workshop planning committee with members from industry and agencies prepared specific case studies focused on some of most difficult situations. The workshop was separated into three major sessions (P1 - Regulatory Perspective; P2 - Challenges in Biosimilar Development; P3 - Demonstrating Analytical Similarity) and each session attempted to provide practical solutions to the relevant case studies. This first session explored the challenges encountered with submission of biosimilar marketing applications from the regulatory agencies' perspectives. Expectations for a successful submission of the CMC information were described. The second session addressed high-level technical challenges frequently encountered during biosimilar candidate development, including data quality expectations, the creation of the final control strategy, and strategic choices necessary for candidate selection and development. The last session explored the use of statistical tools to provide meaningful contributions to the demonstration of analytical similarity and practical challenges that arise during the application of statistical tools.

Protonation of a biologically relevant Cu(II) µ-thiolate complex: ligand dissociation or formation of a protonated Cu(I) disulfide species?

The proton-induced electron-transfer reaction of a Cu(II) µ-thiolate complex to a Cu(I) -containing species has been investigated, both experimentally and computationally. The Cu(II) µ-thiolate complex [Cu(II) 2 (L(Me) S)2 ](2+) is isolated with the new pyridyl-containing ligand L(Me) SSL(Me) , which can form both Cu(II) thiolate and Cu(I) disulfide complexes, depending on the solvent. Both the Cu(II) and the Cu(I) complexes show reactivity upon addition of protons. The multivalent tetranuclear complex [Cu(I) 2 Cu(II) 2 (LS)2 (CH3 CN)6 ](4+) crystallizes after addition of two equivalents of strong acid to a solution containing the µ-thiolate complex [Cu(II) 2 (LS)2 ](2+) and is further analyzed in solution. This study shows that, upon addition of protons to the Cu(II) thiolate compound, the ligand dissociates from the copper centers, in contrast to an earlier report describing redox isomerization to a Cu(I) disulfide species that is protonated at the pyridyl moieties. Computational studies of the protonated Cu(II) µ-thiolate and Cu(I) disulfide species with LSSL show that already upon addition of two equivalents of protons, ligand dissociation forming [Cu(I) (CH3 CN)4 ](+) and protonated ligand is energetically favored over conversion to a protonated Cu(I) disulfide complex.

Thermodynamics of the Cu(II) µ-thiolate and Cu(I) disulfide equilibrium: a combined experimental and theoretical study.

The redox equilibrium between dinuclear Cu(II) µ-thiolate and Cu(I) disulfide structures has been analyzed experimentally and via DFT calculations. Two new ligands, L(2)SSL(2) and L(4)SSL(4), and their Cu(II) µ-thiolate and Cu(I) disulfide complexes were synthesized. For L(2)SSL(2), these two redox-isomeric copper species are shown to be in equilibrium, which depends on both temperature and solvent. For L(4)SSL(4) the µ-thiolate species forms as the kinetic product and further evolves into the disulfide complex under thermodynamic control, which creates the unprecedented possibility to compare both species under the same reaction conditions. The energies of the µ-thiolate and disulfide complexes for two series of related ligands have been calculated with DFT; the results rationalize the experimentally observed structures, and emphasize the important role that steric requirements play in the formation of the Cu(II) thiolate structure.