Literature Search Protocol ▼
A Literature Search Protocol is a pre-specified document that defines the methodology for conducting a systematic literature search, including the databases to be searched, the search terms and Boolean operators to be used, date ranges, language restrictions, and any other search parameters. The protocol ensures that the literature search is comprehensive, reproducible, and free from selection bias. The protocol must be developed before the search is executed and should align with the research question defined in the systematic review plan. It typically includes the rationale for database selection, the search strategy for each database (with free-text terms and controlled vocabulary), supplementary search methods (hand-searching key journals, reference list checking, grey literature), and the process for managing and deduplicating search results. The search protocol is a required component of regulatory SLRs and demonstrates the rigor of the evidence identification process.
Search Strategy Documentation ▼
Search Strategy Documentation provides a complete, transparent record of the literature search methodology used in a systematic review, including the exact search strings used in each database, the date of each search, the number of results retrieved, and any filters or limitations applied. This documentation enables independent replication of the search and demonstrates the comprehensiveness of the evidence identification process. The documentation must include the rationale for database selection, the development process for search terms (including how MeSH/Emtree terms and free-text synonyms were identified), the Boolean logic used to combine terms, and any deviations from the pre-specified search protocol. Complete search strategy documentation is a regulatory requirement for SLRs supporting clinical evaluations and is a key element reviewed by Notified Bodies and regulatory authorities to assess the rigor of the evidence base.
Targeted Literature Reviews ▼
Targeted Literature Reviews are focused, structured reviews of the scientific literature that address specific, narrowly defined questions without the comprehensive scope of a full systematic literature review. They are used when a complete SLR is not warranted or practical, such as for updating an existing review, addressing a specific safety concern, evaluating a particular aspect of clinical performance, or supporting a focused regulatory question. While less comprehensive than full SLRs, targeted reviews still follow a documented methodology with defined search strategies, inclusion criteria, and data extraction approaches. They are commonly used for PMCF literature reviews, safety signal assessment, state-of-the-art updates, and answering specific regulatory questions. The level of rigor must be appropriate for the purpose and should be clearly stated in the review methodology to avoid misrepresentation as a comprehensive systematic review.
Targeted Literature Reviews are focused, structured reviews of the scientific literature that address specific, narrowly defined questions without the comprehensive scope of a full systematic literature review. They are used when a complete SLR is not warranted or practical, such as for updating an existing review, addressing a specific safety concern, evaluating a particular aspect of clinical performance, or supporting a focused regulatory question. While less comprehensive than full SLRs, targeted reviews still follow a documented methodology with defined search strategies, inclusion criteria, and data extraction approaches. They are commonly used for PMCF literature reviews, safety signal assessment, state-of-the-art updates, and answering specific regulatory questions. The level of rigor must be appropriate for the purpose and should be clearly stated in the review methodology to avoid misrepresentation as a comprehensive systematic review.
PICO Development is the process of formulating a structured clinical research question using the PICO framework: Population (the patient group of interest), Intervention (the device, drug, or test being evaluated), Comparator (the alternative treatment or reference standard), and Outcomes (the clinical endpoints of interest). For IVD performance evaluations, this may be adapted to include specific performance parameters. A well-developed PICO question is essential for directing the systematic literature review, as it defines the scope of the search, the inclusion and exclusion criteria for study selection, and the parameters for data extraction and synthesis. The PICO framework must be defined at the outset of the review process and documented in the review protocol. Multiple PICO questions may be needed to address all relevant aspects of a device's clinical evaluation, such as safety, efficacy, and comparison with alternative treatments.
An Evidence Gap Analysis systematically identifies areas where the available clinical evidence is insufficient to fully support a product's clinical evaluation, regulatory claims, or reimbursement arguments. It maps the existing evidence against regulatory requirements, clinical questions, and evidence standards to identify gaps that need to be addressed through additional studies, data collection, or other evidence generation activities. The analysis typically follows the systematic literature review and clinical data appraisal, evaluating whether the evidence adequately addresses all aspects of the device's safety, performance, and benefit-risk profile. Identified gaps may include insufficient long-term follow-up data, lack of evidence in certain patient subgroups, absence of comparative data against current standard of care, or inadequate data on specific safety endpoints. The gap analysis provides a prioritized roadmap for additional evidence generation activities.
SLR for Regulatory Submissions ▼
A Systematic Literature Review is a rigorous, reproducible methodology for identifying, evaluating, and synthesizing all available evidence related to a specific research question. In the context of medical devices, pharmaceuticals, and IVDs, SLRs are conducted to support clinical evaluation reports, performance evaluation reports, regulatory submissions, health technology assessments, and clinical guidelines. The methodology follows established frameworks such as the Cochrane Handbook or PRISMA guidelines. An SLR involves developing a structured research question (typically using the PICO framework), executing comprehensive literature searches across multiple databases, screening results against predefined inclusion and exclusion criteria, appraising the quality of included studies, extracting relevant data, and synthesizing findings. The review must be transparent and reproducible, with every step documented to allow independent verification. SLRs provide the strongest form of literature-based evidence and are increasingly required by regulatory authorities.
Proof of Concept Reports ▼
A Meta-Analysis is a statistical technique that combines the results of multiple independent studies addressing the same research question to produce a single, more precise estimate of effect. By pooling data from multiple studies, meta-analysis increases statistical power, improves precision of effect estimates, and can resolve discrepancies between studies with conflicting results. Meta-analysis requires careful methodological planning including assessment of study heterogeneity (using I-squared and Q statistics), selection of appropriate statistical models (fixed-effect or random-effects), sensitivity analyses, publication bias assessment (funnel plots, Egger's test), and subgroup analyses where appropriate. The results are typically presented as forest plots showing individual study effects and the pooled estimate. Meta-analyses are considered among the highest levels of clinical evidence and are increasingly expected in regulatory submissions and HTA dossiers.
A Network Meta-Analysis (also called mixed-treatment comparison) extends traditional meta-analysis by enabling simultaneous comparison of multiple treatments, even when they have not been directly compared in head-to-head trials. By combining direct evidence (from trials comparing treatments A vs. B) with indirect evidence (derived through common comparators), NMA produces a comprehensive ranking of all treatments in the network. NMA is particularly valuable for health technology assessments and regulatory submissions when direct comparative data is limited. The methodology requires evaluation of the transitivity assumption (that indirect comparisons are valid), assessment of consistency between direct and indirect evidence, and appropriate handling of heterogeneity. Results are typically presented as league tables, rankograms, and surface under the cumulative ranking curves (SUCRA). NMA requires specialized statistical expertise and careful interpretation of results.
Indirect Treatment Comparison ▼
An Indirect Treatment Comparison is a statistical analysis method used to compare the effectiveness of two treatments that have not been directly compared in a clinical trial, by using data from trials that share a common comparator. For example, if Treatment A and Treatment B have both been compared to placebo in separate trials, their relative effectiveness can be estimated indirectly through the shared placebo comparison. Indirect treatment comparisons require careful assessment of the similarity of the compared trials (in terms of patient populations, study designs, outcome measures, and follow-up durations) to ensure the validity of the indirect comparison. The Bucher method is the most commonly used approach for simple indirect comparisons. These analyses are particularly useful when head-to-head clinical trials are not available and are frequently employed in HTA submissions and systematic reviews to provide a more complete picture of the relative treatment landscape.
Comparative Effectiveness Research ▼
Comparative Device Analysis or Comparative Effectiveness Research involves the systematic evaluation of a medical product's performance, safety, and clinical outcomes relative to alternative products, treatments, or standard of care practices. For medical devices and IVDs, this includes comparison with equivalent devices, predicate devices, or competing technologies. For pharmaceuticals, it encompasses comparative effectiveness research evaluating different treatment options. These analyses draw on data from head-to-head clinical trials, observational studies, registries, and indirect comparisons through network meta-analysis. They are essential for clinical evaluations, regulatory submissions (particularly equivalence-based arguments), health technology assessments, and value dossiers. The analysis must use appropriate statistical methods, account for differences in study designs and populations, and present results in a clinically meaningful context.
Health Technology Assessment (HTA) ▼
Health Technology Assessment is a multidisciplinary process that uses explicit methods to evaluate the clinical effectiveness, cost-effectiveness, and broader impact of health technologies to inform healthcare policy and reimbursement decisions. HTA reports synthesize evidence on a technology's benefits, risks, costs, and organizational implications to help decision-makers allocate healthcare resources effectively. HTA submissions follow country-specific requirements (such as NICE in the UK, G-BA in Germany, or HAS in France) and typically include systematic reviews of clinical evidence, economic modeling (cost-effectiveness and budget impact analyses), patient-reported outcomes, and ethical and organizational considerations. The HTA process is increasingly important for market access, particularly in Europe where the EU Health Technology Assessment Regulation (EU 2021/2282) is establishing joint clinical assessments.
PRISMA Flow Diagrams are standardized graphical representations that document the flow of studies through the systematic review process, from initial identification through screening, eligibility assessment, and final inclusion. The diagram shows the number of records identified from each source, duplicates removed, records screened, full-text articles assessed, studies excluded at each stage (with reasons), and studies included in the final synthesis. The PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) flow diagram is a required element of systematic literature reviews and ensures transparency in the study selection process. It allows readers and regulatory reviewers to assess the comprehensiveness of the search, understand the reasons for study exclusion, and evaluate potential selection bias. The 2020 update to the PRISMA guidelines introduced additional elements including identification of records from registers and other sources.
Evidence Tables are structured summaries that present key data extracted from individual studies included in a systematic literature review. They organize study characteristics, population details, interventions, comparators, outcomes, results, and quality assessments in a standardized tabular format that facilitates comparison across studies and supports the evidence synthesis process. Evidence tables serve as both a data management tool and a transparent record of the information extracted from each study. They are essential for demonstrating to regulatory reviewers that data extraction was conducted systematically and consistently. The format and content of evidence tables should align with the review's PICO questions and the regulatory requirements for the clinical evaluation. They are a required component of CERs, PERs, and other regulatory documents that rely on systematic literature evidence.
Quality Assessment (GRADE) ▼
Quality Assessment using the GRADE (Grading of Recommendations, Assessment, Development and Evaluations) methodology is a systematic approach to rating the certainty of evidence across studies for each outcome. GRADE evaluates five domains: risk of bias, inconsistency, indirectness, imprecision, and publication bias, which can downgrade evidence quality, and three domains (large effect, dose-response, and residual confounding) that can upgrade it. GRADE assessment results in evidence being rated as high, moderate, low, or very low certainty, reflecting the confidence that the true effect lies close to the estimated effect. This methodology is widely recognized by regulatory authorities, HTA agencies, and clinical guideline developers. Quality assessment documentation must include a detailed rationale for each rating decision, typically presented in GRADE evidence profile tables and summary of findings tables.
Manuscript Writing involves the development of scientific manuscripts for publication in peer-reviewed journals. These manuscripts may report the results of clinical trials, performance studies, observational studies, meta-analyses, or other scientific investigations. The writing follows the specific requirements of the target journal, including word limits, formatting guidelines, and reporting standards (e.g., CONSORT, STROBE, STARD, PRISMA). Professional manuscript writing requires the ability to present complex scientific data in a clear, logical narrative that meets the standards of the peer-review process. This includes structuring the introduction to establish context and rationale, presenting methods with sufficient detail for reproducibility, reporting results accurately and comprehensively, and discussing findings in the context of existing literature. All manuscripts must comply with ICMJE (International Committee of Medical Journal Editors) guidelines regarding authorship, disclosure, and publication ethics.
Publication Planning is the strategic development of a comprehensive plan for disseminating clinical and scientific data through peer-reviewed publications, conference presentations, and other scientific communications. The plan identifies publication opportunities based on available and anticipated data, prioritizes manuscripts and presentations, establishes timelines, assigns authorship and responsibilities, and coordinates activities across multiple publication projects. A well-designed publication plan ensures that a product's clinical evidence is communicated to the scientific community in a timely, strategic, and ethical manner. It aligns publication activities with the product's overall medical and commercial strategy while maintaining scientific integrity and compliance with publication ethics (GPP3 guidelines). The plan is typically maintained as a living document that evolves as clinical programs progress and new data become available.
