Uncertainty management in regulatory and health technology assessment decision-making on drugs: guidance of the HTAi-DIA Working Group.

OBJECTIVES: Uncertainty is a fundamental component of decision making regarding access to and pricing and reimbursement of drugs. The context-specific interpretation and mitigation of uncertainty remain major challenges for decision makers. Following the 2021 HTAi Global Policy Forum, a cross-sectoral, interdisciplinary HTAi-DIA Working Group (WG) was initiated to develop guidance to support stakeholder deliberation on the systematic identification and mitigation of uncertainties in the regulatory-HTA interface. METHODS: Six online discussions among WG members (Dec 2021-Sep 2022) who examined the output of a scoping review, two literature-based case studies and a survey; application of the initial guidance to a real-world case study; and two international conference panel discussions. RESULTS: The WG identified key concepts, clustered into twelve building blocks that were collectively perceived to define uncertainty: "unavailable," "inaccurate," "conflicting," "not understandable," "random variation," "information," "prediction," "impact," "risk," "relevance," "context," and "judgment." These were converted into a checklist to explain and define whether any issue constitutes a decision-relevant uncertainty. A taxonomy of domains in which uncertainty may exist within the regulatory-HTA interface was developed to facilitate categorization. The real-world case study was used to demonstrate how the guidance may facilitate deliberation between stakeholders and where additional guidance development may be needed. CONCLUSIONS: The systematic approach taken for the identification of uncertainties in this guidance has the potential to facilitate understanding of uncertainty and its management across different stakeholders involved in drug development and evaluation. This can improve consistency and transparency throughout decision processes. To further support uncertainty management, linkage to suitable mitigation strategies is necessary.

Diversity in Health Informatics: Mentoring and Leadership.

Diversity, inclusion and interdisciplinary collaboration are drivers for healthcare innovation and adoption of new, technology-mediated services. The importance of diversity has been highlighted by the United Nations' in SDG5 "Achieve gender equality and empower all women and girls", to drive adoption of social and digital innovation. Women play an instrumental role in health care and are in position to bring about significant changes to support ongoing digitalization and transformation. At the same time, women are underrepresented in Science, Technology, Engineering and Mathematics (STEM). To some extent, the same holds for health care informatics. This paper sums up input to strategies for peer mentoring to ensure diversity in health informatics, to target systemic inequalities and build sustainable, intergenerational communities, improve digital health literacy and build capacity in digital health without losing the human touch.

Outcomes After Drug-Coated Balloon Treatment of Femoropopliteal Lesions in Patients With Critical Limb Ischemia: A Post Hoc Analysis From the IN.PACT Global Study.

PURPOSE: To report a post hoc analysis performed to evaluate 1-year safety and efficacy of the IN.PACT Admiral drug-coated balloon (DCB) for the treatment of femoropopliteal lesions in subjects with critical limb ischemia (CLI) enrolled in the IN.PACT Global study ( ClinicalTrials.gov identifier NCT01609296). MATERIALS AND METHODS: Of 1535 subjects enrolled in the study, 156 participants (mean age 71.8±10.4; 87 men) with CLI (Rutherford categories 4,5) were treated with DCB angioplasty in 194 femoropopliteal lesions. This cohort was compared to the 1246 subjects (mean age 68.2±10.0 years; 864 men) with intermittent claudication (IC) treated for 1573 lesions. The CLI cohort had longer lesions (13.9±10.6 vs 11.9±9.4 cm, p=0.009) and a higher calcification rate (76.8% vs 67.7%, p=0.011). Major adverse events [MAE; composite of all-cause mortality, clinically-driven target lesion revascularization (CD-TLR), major (above-ankle) target limb amputation, and thrombosis at the target lesion site], lesion and vessel revascularization rates, and EuroQol-5D were assessed through 1 year. The Kaplan-Meier method was used to estimate survival, CD-TLR, and amputation events; estimates are presented with the 95% confidence intervals (CI). RESULTS: Estimates of 12-month freedom from major target limb amputation were 98.6% (95% CI 96.7% to 100.0%) in subjects with CLI and 99.9% (95% CI 99.8% to 100.0%) in subjects with IC (p=0.002). Freedom from CD-TLR through 12 months was 86.3% (95% CI 80.6% to 91.9%) in CLI subjects and 93.4% (95% CI 91.9% to 94.8%) in IC subjects (p<0.001). The MAE rate through 12 months was higher in CLI subjects (22.5% vs 10.7%, p<0.001), and CLI patients had poorer overall survival (93.0%, 95% CI 88.9% to 97.2%) than IC subjects (97.0%, 95% CI 96.0% to 97.9%, p=0.011). Health status significantly improved in all domains at 6 and 12 months in both groups. CONCLUSION: Treatment of femoropopliteal disease with DCB in CLI patients is safe through 12-month follow-up, with a low major amputation rate of 1.4%. The rates of MAE and CD-TLR were higher in CLI subjects and reinterventions were required sooner. Additional research is needed to evaluate long-term outcomes of DCB treatment for femoropopliteal lesions in CLI patients.

Novel protein interactions with endoglin and activin receptor-like kinase 1: potential role in vascular networks.

Endoglin and activin receptor-like kinase 1 are specialized transforming growth factor-beta (TGF-ß) superfamily receptors, primarily expressed in endothelial cells. Mutations in the corresponding ENG or ACVRL1 genes lead to hereditary hemorrhagic telangiectasia (HHT1 and HHT2 respectively). To discover proteins interacting with endoglin, ACVRL1 and TGF-ß receptor type 2 and involved in TGF-ß signaling, we applied LUMIER, a high-throughput mammalian interactome mapping technology. Using stringent criteria, we identified 181 novel unique and shared interactions with ACVRL1, TGF-ß receptor type 2, and endoglin, defining potential novel important vascular networks. In particular, the regulatory subunit B-beta of the protein phosphatase PP2A (PPP2R2B) interacted with all three receptors. Interestingly, the PPP2R2B gene lies in an interval in linkage disequilibrium with HHT3, for which the gene remains unidentified. We show that PPP2R2B protein interacts with the ACVRL1/TGFBR2/endoglin complex and recruits PP2A to nitric oxide synthase 3 (NOS3). Endoglin overexpression in endothelial cells inhibits the association of PPP2R2B with NOS3, whereas endoglin-deficient cells show enhanced PP2A-NOS3 interaction and lower levels of endogenous NOS3 Serine 1177 phosphorylation. Our data suggest that endoglin regulates NOS3 activation status by regulating PPP2R2B access to NOS3, and that PPP2R2B might be the HHT3 gene. Furthermore, endoglin and ACVRL1 contribute to several novel networks, including TGF-ß dependent and independent ones, critical for vascular function and potentially defective in HHT.

Early versus delayed implantation of a loop recorder in patients with unexplained syncope--effects on care pathway and diagnostic yield.

BACKGROUND: This study looked to assess the care pathway and diagnostic yield in patients who received an implantable loop recorder (ILR) after an "initial phase of the diagnostic work-up" (initial work-up) or after a "full evaluation" of unexplained syncope. METHODS AND RESULTS: Physicians classified the timing of an ILR implant in 514 patients as either following an "initial work-up" (n=128; 25%) or "full evaluation" (n=386; 75%). Patients with an "initial work-up" underwent a median (IQ range) of 8 (6-14) tests prior to ILR implant compared to 14 (10-21) tests after "full evaluation" (p<0.0001). Hospitalization and injury before implant were less common in patients with an "initial work-up": 53 vs. 75%, p<0001, and 23% vs. 39%, p<0.001, as were visits to specialists, e.g. neurologist, 32% vs. 50%, p<0.001. At one year after implant, the syncope recurrence rate was 32% in the initial work-up group and 36% in the full evaluation group, and the incidence of recurrences with an ILR-guided diagnosis was 52% and 75% respectively. Diagnoses were cardiac in 90% after "initial work-up" vs. 79% after "full evaluation". CONCLUSIONS: Patients who only underwent an "initial work-up" had fewer investigations and a lower incidence of injury or hospitalization. The diagnostic yield from the ILR was high in both groups. Patients in both groups underwent more investigations than suggested in the ESC guidelines and could have benefitted from limiting the initial evaluation before an ILR is implanted.

Use of an implantable loop recorder to increase the diagnostic yield in unexplained syncope: results from the PICTURE registry.

AIMS: To collect information on the use of the Reveal implantable loop recorder (ILR) in the patient care pathway and to investigate its effectiveness in the diagnosis of unexplained recurrent syncope in everyday clinical practice. METHODS AND RESULTS: Prospective, multicentre, observational study conducted in 2006-2009 in 10 European countries and Israel. Eligible patients had recurrent unexplained syncope or pre-syncope. Subjects received a Reveal Plus, DX or XT. Follow up was until the first recurrence of a syncopal event leading to a diagnosis or for ≥1 year. In the course of the study, patients were evaluated by an average of three different specialists for management of their syncope and underwent a median of 13 tests (range 9-20). Significant physical trauma had been experienced in association with a syncopal episode by 36% of patients. Average follow-up time after ILR implant was 10±6 months. Follow-up visit data were available for 570 subjects. The percentages of patients with recurrence of syncope were 19, 26, and 36% after 3, 6, and 12 months, respectively. Of 218 events within the study, ILR-guided diagnosis was obtained in 170 cases (78%), of which 128 (75%) were cardiac. CONCLUSION: A large number of diagnostic tests were undertaken in patients with unexplained syncope without providing conclusive data. In contrast, the ILR revealed or contributed to establishing the mechanism of syncope in the vast majority of patients. The findings support the recommendation in current guidelines that an ILR should be implanted early rather than late in the evaluation of unexplained syncope.

Multivalent recombinant proteins for probing functions of leucocyte surface proteins such as the CD200 receptor.

CD200 (OX2) is a membrane glycoprotein that interacts with a structurally related receptor (CD200R) involved in the regulation of macrophage function. The interaction is of low affinity (K(D) approximately 1 microm) but can be detected using CD200 displayed in a multivalent form on beads or with dimeric fusion proteins consisting of the extracellular region of CD200 and immunoglobulin Fc regions. We prepared putative pentamers and trimers of mouse CD200 with sequences from cartilage oligomeric matrix protein (COMP) and surfactant protein D (SP-D), respectively. The COMP protein gave high-avidity binding and was a valuable tool for showing the interaction whilst the SP-D protein gave weak binding. In vivo experiments showed that an agonistic CD200R monoclonal antibody caused some amelioration in a model of experimental autoimmune encephalomyelitis but the COMP protein was cleared rapidly and had minimal effect. Pentameric constructs also allowed detection of the rat CD48/CD2 interaction, which is of much lower affinity (K(D) approximately 70 microm). These reagents may have an advantage over Fc-bearing hybrid molecules for probing cell surface proteins without side-effects due to the Fc regions. The CD200-COMP gave strong signals in protein microarrays, suggesting that such reagents may be valuable in high throughput detection of weak interactions.

Analysis of leukocyte membrane protein interactions using protein microarrays.

BACKGROUND: Protein microarrays represent an emerging class of proteomic tools to investigate multiple protein-protein interactions in parallel. A sufficient proportion of immobilized proteins must maintain an active conformation and an orientation that allows for the sensitive and specific detection of antibody and ligand binding. In order to establish protein array technology for the characterization of the weak interactions between leukocyte membrane proteins, we selected the human leukocyte membrane protein CD200 (OX2) and its cell surface receptor (hCD200R) as a model system. As antibody-antigen reactions are generally of higher affinity than receptor-ligand binding, we first analyzed the reactivity of monoclonal antibodies (mAb) to normal and mutant forms of immobilized CD200R. RESULTS: Fluorescently labelled mAb DX147, DX136 and OX108 were specifically reactive with immobilized recombinant hCD200R extracellular region, over a range of 0.1-40 microg ml(-1) corresponding to a limit of sensitivity of 0.01-0.05 femtomol per spot. Orientating hCD200R using capture antibodies, showed that DX147 reacts with an epitope spatially distinct from the more closely related DX136 and OX108 epitopes. A panel of soluble recombinant proteins with mutations in hCD200R domain 1 produced by transiently transfected cells, was arrayed directly without purification and screened for binding to the three mAb. Several showed decreased binding to the blocking mAb DX136 and OX108, suggesting close proximity of these epitopes to the CD200 binding site. Binding of hCD200 to directly immobilized rat, mouse, and hCD200R was achieved with multimeric ligands, in the form of biotinylated-hCD200 coupled to FITC-labelled avidin coated beads. CONCLUSION: We have achieved sensitive, specific and reproducible detection of immobilized CD200R with different antibodies and mapped antigenic epitopes for two mAb in the vicinity of the ligand binding site using protein microarrays. We also detected CD200 binding to its receptor, a low affinity interaction, using beads presenting multivalent ligands. Our results demonstrate the quantitative aspects of protein arrays and their potential use in detecting simultaneously multiple protein-protein interactions and in particular the weak interactions found between leukocyte membrane proteins.