Reflections on a Copenhagen-Minneapolis Axis in Bioorganic Chemistry.

The international peptide community rejoiced when one of its most distinguished members, Morten Meldal of Denmark, shared the 2022 Nobel Prize in Chemistry. In fact, the regiospecific solid-phase "copper(I)-catalyzed 1,3-dipolar cycloaddition of terminal alkynes to azides" (CuACC) reaction-that formed the specific basis for Meldal's recognition-was reported first at the 17th American Peptide Symposium held in San Diego in June 2001. The present perspective outlines intertwining conceptual and experimental threads pursued concurrently in Copenhagen and Minneapolis, sometimes by the same individuals, that provided context for Meldal's breakthrough discovery. Major topics covered include orthogonality in chemistry; the dithiasuccinoyl (Dts) protecting group for amino groups in α-amino acids, carbohydrates, and monomers for peptide nucleic acids (PNA); and poly(ethylene glycol) (PEG)-based solid supports such as PEG-PS, PEGA, and CLEAR [and variations inspired by them] for solid-phase peptide synthesis (SPPS), solid-phase organic synthesis (SPOS), and combinatorial chemistry that can support biological assays in aqueous media.

Nanogel delivery systems for cationic peptides: More than a 'One Size Fits All' solution.

Self-assembled hyaluronic acid-based nanogels are versatile drug carriers due to their biodegradable nature and gentle preparation conditions, making them particularly interesting for delivery of peptide therapeutics. This study aims to elucidate the relation between peptide structure and encapsulation in a nanogel. Key peptide properties that affect encapsulation in octenyl succinic anhydride-modified hyaluronic acid nanogels were identified as we explored the effect on nanogel characteristics using 12 peptides with varying charge and hydrophobicity. The size and surface properties of the microfluidics-assembled peptide-loaded nanogels were evaluated using dynamic light scattering, laser Doppler electrophoresis, and small angle neutron scattering. Additionally, the change in peptide secondary structure upon encapsulation in nanogels, their release from the nanogels, and the in vitro antimicrobial activity were assessed. In conclusion, the more hydrophobic peptides showed stronger binding to the nanogel carrier and localized internally rather than on the surface of the nanogel, resulting in more spherical nanogels with smoother surfaces and slower release profiles. In contrast, cationic and hydrophilic peptides localized at the nanogel surface resulting in fluffier nanogel structures and quick and more complete release in biorelevant medium. These findings emphasize that the advantages of nanogel delivery systems for different applications depend on the therapeutic peptide properties.

Embedding stakeholder preferences in setting priorities for health research: Using a discrete choice experiment to develop a multi-criteria tool for evaluating research proposals.

We determined weights for a multi-criteria tool for assessing the relative merits of clinical-trial research proposals, and investigated whether the weights vary across relevant stakeholder groups. A cross-sectional, adaptive discrete choice experiment using 1000minds online software was administered to consumers, researchers and funders affiliated with the Australian Clinical Trials Alliance (ACTA). We identified weights for four criteria-Appropriateness, Significance, Relevance, Feasibility-and their levels, representing their relative importance, so that research proposals can be scored between 0% (nil or very low merit) and 100% (very high merit). From 220 complete survey responses, the most important criterion was Appropriateness (adjusted for differences between stakeholder groups, mean weight 28.9%) and the least important was Feasibility (adjusted mean weight 19.5%). Consumers tended to weight Relevance more highly (2.7% points difference) and Feasibility less highly (3.1% points difference) than researchers. The research or grant writing experience of researchers or consumers was not associated with the weights. A multi-criteria tool for evaluating research proposals that reflects stakeholders' preferences was created. The tool can be used to assess the relative merits of clinical trial research proposals and rank them, to help identify the best proposals for funding.

The Y-ome Conundrum: Insights into Uncharacterized Genes and Approaches for Functional Annotation.

The ever-increasing availability of genome sequencing data has revealed a substantial number of uncharacterized genes without known functions across various organisms. The first comprehensive genome sequencing of E. coli K12 revealed that more than 50% of its open reading frames corresponded to transcripts with no known functions. The group of protein-coding genes without a functional description and/or a recognized pathway, beginning with the letter "Y", is classified as the "y-ome". Several efforts have been made to elucidate the functions of these genes and to recognize their role in biological processes. This review provides a brief update on various strategies employed when studying the y-ome, such as high-throughput experimental approaches, comparative omics, metabolic engineering, gene expression analysis, and data integration techniques. Additionally, we highlight recent advancements in functional annotation methods, including the use of machine learning, network analysis, and functional genomics approaches. Novel approaches are required to produce more precise functional annotations across the genome to reduce the number of genes with unknown functions.

Substrate space analysis of the bacterial proton-coupled oligopeptide transporter YdgR by cheminformatics.

Proton-dependent oligopeptide transporters (POTs) are recognized for their substrate promiscuity due to their ability to transport a wide range of substrates. POTs are conserved in all forms of life ranging from bacteria to humans. A dipeptide-fluorophore conjugate, H-(ß-Ala)-Lys(AMCA)-OH, is a well-known substrate of the transporter YdgR that is commonly used as a fluorescent reporter. In order to understand the substrate space of YdgR, we used this dipeptide as a bait reference, when screening an ensemble of compounds (previously tested in PEPT/PTR/NPF space) via a cheminformatic analysis based on the Tanimoto similarity index. Eight compounds (sinalbin, abscisic acid, carnosine, jasmonic acid, N-acetyl-aspartate, N-acetyl-lysine, aspartame, and N-acetyl-aspartylglutamate), covering a wide range on the Tanimoto scale, were tested for YdgR-mediated transport. Carnosine was the only compound observed to be a YdgR substrate based on cell-based transport assays and molecular docking. The other compounds tested were neither inhibitors nor substrates. Thus, we found that neither the Tanimoto similarity index nor ADME (absorption, distribution, metabolism, and excretion) properties appear useful for the identification of substrates (e.g., dipeptides) in YdgR-mediated drug transport.

Physiological response in E. coli to YdgR overexpression depends on whether the protein has an intact function.

Membrane transport proteins are essential for the transport of a wide variety of molecules across the cell membrane to maintain cellular homeostasis. Generally, these transport proteins can be overexpressed in a suitable host (bacteria, yeast, or mammalian cells), and it is well documented that overexpression of membrane proteins alters the global metabolomic and proteomic profiles of the host cells. In the present study, we investigated the physiological consequences of overexpression of a membrane transport protein YdgR that belongs to the POT/PTR family from E. coli by using the lab strain BL21 (DE3)pLysS in its functional and attenuated mutant YdgR-E33Q. We found significant differences between the omics (metabolomics and proteomics) profiles of the cells expressing functional YdgR as compared to cells expressing attenuated YdgR, e.g., upregulation of several uncharacterized y-proteins and enzymes involved in the metabolism of peptides and amino acids. Furthermore, molecular network analysis suggested a relatively higher presence of proline-containing tripeptides in cells expressing functional YdgR. We envisage that an in-depth investigation of physiological alterations due to protein over-expression may be used for the deorphanization of the y-gene transportome.

Unagi: Deep Generative Model for Deciphering Cellular Dynamics and In-Silico Drug Discovery in Complex Diseases.

Human diseases are characterized by intricate cellular dynamics. Single-cell sequencing provides critical insights, yet a persistent gap remains in computational tools for detailed disease progression analysis and targeted in-silico drug interventions. Here, we introduce UNAGI, a deep generative neural network tailored to analyze time-series single-cell transcriptomic data. This tool captures the complex cellular dynamics underlying disease progression, enhancing drug perturbation modeling and discovery. When applied to a dataset from patients with Idiopathic Pulmonary Fibrosis (IPF), UNAGI learns disease-informed cell embeddings that sharpen our understanding of disease progression, leading to the identification of potential therapeutic drug candidates. Validation via proteomics reveals the accuracy of UNAGI's cellular dynamics analyses, and the use of the Fibrotic Cocktail treated human Precision-cut Lung Slices confirms UNAGI's predictions that Nifedipine, an antihypertensive drug, may have antifibrotic effects on human tissues. UNAGI's versatility extends to other diseases, including a COVID dataset, demonstrating adaptability and confirming its broader applicability in decoding complex cellular dynamics beyond IPF, amplifying its utility in the quest for therapeutic solutions across diverse pathological landscapes.

C-Locked Analogs of the Antimicrobial Peptide BP214.

BP214 is an all-D antimicrobial peptide amide, kklfkkilryl, which shows an excellent activity against colistin-resistant Acinetobacter baumannii and a low hemolytic activity. The aim of the present work was to investigate how C-terminus-to-side chain macrocyclization and fatty acid modification affect the antimicrobial and hemolytic activity of this peptide. In total, 18 analogs of BP214 were synthesized using a combination of Fmoc-based solid-phase peptide synthesis and the submonomer approach. Cyclization was achieved by reacting the ε-amino group of a C-terminal lysine residue with a bromoacetylgroup attached to the Nα amino group of the N-terminal amino acid, generating a secondary amine at which the exocyclic lipopeptide tail was assembled. Three different ring sizes (i.e., 3-5 amino acid residues) of C-locked analogs combined with fatty acids of different lengths (i.e., C10-C14) were investigated. The antimicrobial activity of the analogs was tested against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa. The most promising compound was analog 13 (MIC = 4 µg/mL (2.4 µM) against E. coli and 36% hemolysis of red blood cells at 150 µM). In a time-kill assay, this peptide showed a significant, concentration-dependent reduction in viable E. coli cells comparable to that seen for colistin.

Which countries need COVID-19 vaccines the most? Development of a prioritisation tool.

BACKGROUND: The COVID-19 pandemic and associated non-pharmaceutical interventions (NPIs) have affected all countries. With a scarcity of COVID-19 vaccines there has been a need to prioritize populations, but assessing relative needs has been challenging. The COVAX Facility allocates vaccines to cover 20% of each national population, followed by a needs assessment that considers five quantitative metrics alongside a qualitative assessment. The objective of this study was to identify the most important factors for assessing countries' needs for vaccines, and to weight each, generating a scoring tool for prioritising countries. METHODS: The study was conducted between March and November 2021. The first stage involved an online Delphi survey with a purposive and snowball sample of public health experts, to reach consensus on country-level factors for assessing relative needs for COVID-19 vaccines. The second stage involved a discrete choice experiment (DCE) to determine weights for the most important factors. RESULTS: Responses were received from 28 experts working across 13 different countries and globally. The most common job titles reported were director and professor, with most based in national public health institutes (n = 9) and universities (n = 8). The Delphi survey found 37 distinct factors related to needs. Nine of the most important factors were included in the DCE. Among these, the most important factor was the 'proportion of overall population not fully vaccinated' (with a mean weight of 19.5), followed by 'proportion of high-risk population not fully vaccinated' (16.1), 'health system capacity' (14.2), 'capacity to purchase vaccines' (11.9) and the 'proportion of the population clinically vulnerable' (11.3). CONCLUSIONS: Several factors exist, extending beyond those currently used, which may lead to some countries having a greater need for vaccines compared to others. By assessing relative needs, this scoring tool can build on existing methods to further the role of equity in global COVID-19 vaccine allocation.

Production and Characterization of Peptide Antibodies to the C-Terminal of Frameshifted Calreticulin Associated with Myeloproliferative Diseases.

Myeloproliferative Neoplasms (MPNs) constitute a group of rare blood cancers that are characterized by mutations in bone marrow stem cells leading to the overproduction of erythrocytes, leukocytes, and thrombocytes. Mutations in calreticulin (CRT) genes may initiate MPNs, causing a novel variable polybasic stretch terminating in a common C-terminal sequence in the frameshifted CRT (CRTfs) proteins. Peptide antibodies to the mutated C-terminal are important reagents for research in the molecular mechanisms of MPNs and for the development of new diagnostic assays and therapies. In this study, eight peptide antibodies targeting the C-terminal of CRTfs were produced and characterised by modified enzyme-linked immunosorbent assays using resin-bound peptides. The antibodies reacted to two epitopes: CREACLQGWTE for SSI-HYB 385-01, 385-02, 385-03, 385-04, 385-07, 385-08, and 385-09 and CLQGWT for SSI-HYB 385-06. For the majority of antibodies, the residues Cys1, Trp9, and Glu11 were essential for reactivity. SSI-HYB 385-06, with the highest affinity, recognised recombinant CRTfs produced in yeast and the MARIMO cell line expressing CRTfs when examined in Western immunoblotting. Moreover, SSI-HYB 385-06 occasionally reacted to CRTfs from MPN patients when analysed by flow cytometry. The characterized antibodies may be used to understand the role of CRTfs in the pathogenesis of MPNs and to design and develop new diagnostic assays and therapeutic targets.

Drug-Eluting Bead, Irinotecan Therapy of Unresectable Intrahepatic Cholangiocarcinoma (DELTIC) with Concomitant Systemic Gemcitabine and Cisplatin.

BACKGROUND: Unresectable intrahepatic cholangiocarcinoma (ICC) carries a poor prognosis, and currently there are moderately established chemotherapeutic [gemcitabine/cisplatin (Gem/Cis)] treatments to prolong survival. The purpose of this study was to assess the efficacy of irinotecan drug-eluting beads (DEBIRI) therapy by transarterial infusion in combination with systemic therapy in unresectable ICC. PATIENTS AND METHODS: This is a prospective, multicenter, open-label, randomized phase II study (Clin Trials: NCT01648023-DELTIC trial) of patients with ICC randomly assigned to Gem/Cis with DEBIRI or Gem/Cis alone. The primary endpoint was response rate. RESULTS: The intention-to-treat population comprised 48 patients: 24 treated with Gem/Cis and DEBIRI and 22 with Gem/Cis alone (2 screen failures). The two groups were similar with respect to the extent of liver involvement (35% versus 38%) and presence of extrahepatic disease (29% versus 14%, p = 0.12). Median numbers of chemotherapy cycles were similar (6 versus 6), as were rates of grade 3/4 adverse events (34% for the Gem/Cis-DEBIRI group versus 36% for the Gem/Cis group). The overall response rate was significantly greater in the Gem/Cis-DEBIRI arm versus the Gem/Cis arm at 2 (p < 0.04), 4 (p < 0.03), and 6 months (p < 0.05). There was significantly more downsizing to resection/ablation in the Gem/Cis-DEBIRI arm versus the Gem/Cis arm (25% versus 8%, p < 005), and there was improved median progression-free survival [31.9 (95% CI 8.5-75.3) months versus 10.1 (95% CI 5.3-13.5) months, p = 0.028] and improved overall survival [33.7 (95% CI 13.5-54.5) months versus 12.6 (95% CI 8.7-33.4) months, p = 0.048]. CONCLUSION: Combination Gem/Cis with DEBIRI is safe, and leads to significant improvement in downsizing to resection, improved progression-free survival, and overall survival.

Impact of transitioning patients to oral diuretics 24 hours before discharge from heart failure hospitalization on 30 day outcomes.

BACKGROUND: Patients hospitalized for heart failure (HF) are at high risk for post-discharge events. Although transition from intravenous to oral diuretics for ≥24 h is commonly practiced to reduce post-discharge risk, evidence supporting this strategy is limited. We investigated the impact of this practice on 30 day post-discharge outcomes following HF hospitalization at our institution. METHODS: Retrospective chart review of patients hospitalized with a primary HF diagnosis, discharged on oral diuretic, and followed at our institution. Admission, in-hospital, and pre-discharge characteristics of patients discharged with ≥24-h observation were compared to those of patients observed for <24-h on oral diuretics. Differences between groups in composite 30 day all-cause mortality and rehospitalization, each component, and HF rehospitalization were assessed. RESULTS: Of 285 patients meeting entry criteria, 178 received oral diuretics ≥24 h prior to discharge and 107 were discharged <24 h after transitioning to oral diuretics. Baseline characteristics were similar between groups. Patients with ≥24 h observation on oral diuretics had longer in-hospital stays and greater weight and net volume loss than those observed <24 h. Patients receiving oral diuretics for <24 h were more likely to have had neurohormonal drugs and diuretic dose changed within 24-h of discharge. Oral diuretic treatment for ≥24 h failed to reduce any study endpoint. CONCLUSIONS: Transitioning patients to oral diuretics for ≥24 h prior to discharge following HF hospitalization failed to improve 30-day outcomes. These results question this strategy for all patients hospitalized for worsening HF.

Assessing options for cannabis law reform: A Multi-Criteria Decision Analysis (MCDA) with stakeholders in New Zealand.

BACKGROUND: A number of jurisdictions are considering or implementing different options for cannabis law reform, including New Zealand. Multi-Criteria Decision Analysis (MCDA) helps facilitate the resolution of complex policy decisions by breaking them down into key criteria and drawing on the combined knowledge of experts from various backgrounds. AIMS: To rank cannabis law reform options by facilitating expert stakeholders to express preferences for projected reform outcomes using MCDA. METHODS: A group of cannabis policy experts projected the outcomes of eight cannabis policy options (i.e., prohibition, decriminalization, social clubs, government monopoly, not-for-profit trusts, strict regulation, light regulation, and unrestricted market) based on five criteria (i.e., health and social harm, illegal market size, arrests, tax income, treatment services). A facilitated workshop of 42 key national stakeholders expressed preferences for different reform outcomes and doing so generated relative weights for each criterion and level. The resulting weights were then used to rank the eight policy options. RESULTS: The relative weighting of the criteria were: "reducing health and social harm" (46%), "reducing arrests" (31%), "reducing the illegal market" (13%), "expanding treatment" (8%) and "earning tax" (2%). The top ranked reform options were: "government monopoly" (81%), "not-for-profit" (73%) and "strict market regulation" (65%). These three received higher scores due to their projected lower impact on health and social harm, medium reduction in arrests, and medium reduction in the illegal market. The "lightly regulated market" option scored lower largely due its projected greater increase in health and social harm. "Prohibition" ranked lowest due to its lack of impact on reducing the number of arrests or size of the illegal market. CONCLUSION: Strictly regulated legal market options were ranked higher than both the current prohibition, and alternatively, more lightly regulated legal market options, as they were projected to minimize health and social harms while substantially reducing arrests and the illegal market.

Clinical features and postoperative survival in patients with sporadic versus multiple endocrine neoplasia type 1-related pancreatic neuroendocrine tumors: An international cohort study.

BACKGROUND: The optimal surgical management of pancreatic neuroendocrine tumors in patients with multiple endocrine neoplasia type 1 is controversial. This study sought to compare clinicopathologic characteristics and outcomes of multiple endocrine neoplasia type 1-associated and sporadic pancreatic neuroendocrine tumors from a large multi-national database. METHODS: A multi-institutional, international database of patients with surgically resected pancreatic neuroendocrine tumors was analyzed. The cohort was divided into 2 groups: those with multiple endocrine neoplasia type 1 versus those with sporadic disease. Clinicopathologic comparisons were made. Overall and disease-free survival were analyzed. Propensity score matching was used to reduce bias. RESULTS: Of 651 patients included, 45 (6.9%) had multiple endocrine neoplasia type 1 and 606 sporadic pancreatic neuroendocrine tumors. Multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors were more common in younger patients and associated with multifocal disease at the time of surgery and higher T-stage. Lymph node involvement and the presence of metastasis were similar. Total pancreatectomy rate was 5-fold higher in the multiple endocrine neoplasia type 1 cohort. Median survival did not differ (disease-free survival 126 months multiple endocrine neoplasia type 1 vs 198 months sporadic, P > .5). After matching, survival remained similar (overall survival not reached in either cohort, disease-free survival 126 months multiple endocrine neoplasia type 1 vs 198 months sporadic, P > .5). Equivalence in overall survival and disease-free survival persisted even when patients who underwent subtotal and total pancreatectomy were excluded. CONCLUSION: Multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors are more common in younger patients and are associated with multifocality and higher T-stage. Survival for patients with multiple endocrine neoplasia type 1-associated pancreatic neuroendocrine tumors is comparable to those with sporadic pancreatic neuroendocrine tumors, even in the absence of radical pancreatectomy. Consideration should be given to parenchymal-sparing surgery to preserve pancreatic function.

Peptide Antibody Reactivity to Homologous Regions in Glutamate Decarboxylase Isoforms and Coxsackievirus B4 P2C.

Two isoforms of the glutamate decarboxylase (GAD) enzyme exist, GAD65 and GAD67, which are associated with type 1 diabetes (T1D) and stiff-person syndrome (SPS), respectively. Interestingly, it has been reported that T1D patients seldom develop SPS, whereas patients with SPS occasionally develop T1D. In addition, coxsackievirus B4 (CVB4) has previously been proposed to be involved in the onset of T1D through molecular mimicry. On this basis, we aimed to examine antibody cross-reactivity between a specific region of GAD65 and GAD67, which has high sequence homology to the nonstructural P2C protein of CVB4 to determine potential correlations at antibody level. Monoclonal peptide antibodies generated in mice specific for a region with high similarity in all three proteins were screened for reactivity along with human sera in immunoassays. In total, six antibodies were generated. Two of the antibodies reacted to both GAD isoforms. However, none of the antibodies were cross-reactive to CVB, suggesting that antibody cross-reactivity between GAD65 and CVB, and GAD67 and CVB may not contribute to the onset of T1D and SPS, respectively.

Transcriptomic profiles of neoantigen-reactive T cells in human gastrointestinal cancers.

Tumor-infiltrating neoantigen-reactive T cells can mediate regression of metastatic gastrointestinal cancers yet remain poorly characterized. We performed immunological screening against personalized neoantigens in combination with single-cell RNA sequencing on tumor-infiltrating lymphocytes from bile duct and pancreatic cancer patients to characterize the transcriptomic landscape of neoantigen-reactive T cells. We found that most neoantigen-reactive CD8+ T cells displayed an exhausted state with significant CXCL13 and GZMA co-expression compared with non-neoantigen-reactive bystander cells. Most neoantigen-reactive CD4+ T cells from a patient with bile duct cancer also exhibited an exhausted phenotype but with overexpression of HOPX or ADGRG1 while lacking IL7R expression. Thus, neoantigen-reactive T cells infiltrating gastrointestinal cancers harbor distinct transcriptomic signatures, which may provide new opportunities for harnessing these cells for therapy.

Reactivity of Rheumatoid Arthritis-Associated Citrulline-Dependent Antibodies to Epstein-Barr Virus Nuclear Antigen1-3.

Rheumatoid arthritis (RA) is a chronic disease which causes joint inflammation and, ultimately, erosion of the underlying bone. Diagnosis of RA is based on the presence of biomarkers, such as anti-citrullinated protein antibodies (ACPA) and rheumatoid factors, along with clinical symptoms. Much evidence points to a link between the Epstein-Barr virus and RA. In this study, we analyzed ACPA reactivity to citrullinated peptides originating from Epstein-Barr nuclear antigens (EBNA1, EBNA2, and EBNA3) in order to elaborate the diagnostic potential of citrullinated EBNA peptides. Moreover, ACPA cross-reactivity to citrullinated peptides from myelin basic protein (MBP) was analyzed, as citrullinated MBP recently was described to be associated with multiple sclerosis, and some degree of sequence homology between MBP and citrullinated EBNA exists. A peptide from EBNA2, (EBNA2-A, GQGRGRWRG-Cit-GSKGRGRMH) reacted with approximately 70% of all RA sera, whereas only limited reactivity was detected to EBNA1 and EBNA3 peptides. Moreover, screening of ACPA reactivity to hybrid peptides of EBNA3-A (EPDSRDQQS-Cit-GQRRGDENRG) and EBNA2-A and peptides containing citrulline close to the N-terminal confirmed that ACPA sera contain different populations of ACPAs. No notable ACPA reactivity to MBP peptides was found, confirming that ACPAs are specific for RA, and that other factors than the presence of a central Cit-Gly motif are crucial for antibody binding. Collectively, these findings illustrate that citrullinated EBNA2 is an optimal candidate for ACPA detection, supporting current evidence that EBV is linked to RA onset.

Case Report: Sequential Transarterial and Trans-Cortical Venous Embolization of a Mixed Pial-Dural AVM.

Endovascular therapy is the primary treatment modality for dural arteriovenous fistulas. Pre-treatment angiographic evaluation of dural fistulas must rule out the presence of a mixed pial component or supply from pial-dural collaterals, as the pial supply must be closed before definitive occlusion of the draining vein to prevent iatrogenic rupture. In this report, we described a case of a mixed pial-dural arterial venous malformation (AVM), which was effectively treated with a sequential transarterial and trans-cortical venous embolization.

Development of radiographic classification criteria for hand osteoarthritis: a methodological report (Phase 2).

OBJECTIVES: In Phase 1 of developing new hand osteoarthritis (OA) classification criteria, features associated with hand OA were identified in a population with hand complaints. Radiographic findings could better discriminate patients with hand OA and controls than clinical examination findings. The objective of Phase 2 was to achieve consensus on the features and their weights to be included in three radiographic criteria sets of overall hand OA, interphalangeal OA and thumb base OA. METHODS: Multidisciplinary, international expert panels were convened. Patient vignettes were used to identify important features consistent with hand OA. A consensus-based decision analysis approach implemented using 1000minds software was applied to identify the most important features and their relative importance influencing the likelihood of symptoms being due to hand OA. Analyses were repeated for interphalangeal and thumb base OA. The reliability and validity of the proposed criteria sets were tested. RESULTS: The experts agreed that the criteria sets should be applied in a population with pain, aching or stiffness in hand joint(s) not explained by another disease or acute injury. In this setting, five additional criteria were considered important: age, morning stiffness, radiographic osteophytes, radiographic joint space narrowing and concordance between symptoms and radiographic findings. The reliability and validity were very good. CONCLUSION: Radiographic features were considered critical when determining whether a patient had symptoms due to hand OA. The consensus-based decision analysis approach in Phase 2 complemented the data-driven results from Phase 1, which will form the basis of the final classification criteria sets.