State of the Art Review for Medical Devices: SOTA Methods, Comparator Selection, and CER Examples

Why SOTA Is the Foundation of Clinical Evaluation

Under EU MDR 2017/745, the state of the art (SOTA) review is not optional background — it is the benchmark against which your device's safety, performance, and benefit-risk profile are measured. Notified Bodies expect manufacturers to demonstrate that their device meets or exceeds current clinical practice, not outdated norms. A weak or poorly constructed SOTA section is one of the most common reasons for CER nonconformities during conformity assessment.

SOTA serves multiple functions within the clinical evaluation: it establishes clinical context, identifies acceptable performance benchmarks, defines the benefit-risk comparator, informs risk management, and supports the determination of whether clinical evidence is sufficient. Without a rigorous SOTA, none of the downstream conclusions in the CER can be adequately defended.

Regulatory Definitions and Framework

What SOTA Means Under EU MDR

The MDR does not provide a prescriptive definition of SOTA. However, several authoritative sources establish the concept:

• ISO/IEC Guide 2:2004, referenced in MEDDEV 2.7/1 Rev. 4: "Developed stage of current technical capability and/or accepted clinical practice in regard to products, processes and patient management, based on the relevant consolidated findings of science, technology and experience. Note: The state of the art embodies what is currently and generally accepted as good practice in technology and medicine. The state of the art does not necessarily imply the most technologically advanced solution."

• MDCG 2020-6, drawing on IMDRF/GRRP WG/N47: Defines SOTA as the "developed stage of current technical capability and/or accepted clinical practice in regard to products, processes and patient management, based on the relevant consolidated findings of science, technology and experience."

• MEDDEV 2.7/1 Rev. 4 Section 8.2: Specifies that SOTA includes applicable standards, guidance documents, data on benchmark devices, medical alternatives, and specific medical conditions and patient populations.

Key Regulatory Provisions

A Practical Framework for Conducting a SOTA Review

Step 1: Define the Clinical Background

Begin by establishing the medical context in which the device operates. Document:

Disease or condition:

• Pathophysiology and disease progression
• Epidemiology (prevalence, incidence)
• Patient population characteristics (age, sex, comorbidities)
• Disease severity classification and staging
• Unmet clinical needs

Current management approaches:

• Established treatment algorithms and clinical guidelines
• Pharmacological treatments
• Surgical or interventional procedures
• Medical devices currently in use
• Watchful waiting or conservative management

Clinical practice guidelines:

• European Society of Cardiology (ESC), European Association of Urology (EAU), or other relevant specialty society guidelines
• National guidelines (NICE, AWMF, HAS)
• Consensus statements and position papers

Step 2: Identify and Characterize SOTA Devices

SOTA devices are the products currently available on the market that represent the accepted standard of care. They serve as comparators for your device's safety and performance.

Types of SOTA comparators:

Selecting benchmark devices:

• Choose devices that are currently CE marked and actively marketed
• Select devices representing the highest market share or strongest clinical evidence base
• Include multiple devices when no single device dominates the market
• Justify your selection criteria (market share, clinical evidence quality, guideline recommendations)

Critical point: Benchmarks should be based on composite or collected data from multiple products showing acceptable performance — such as systematic reviews or registry evaluations. Selecting individual products as benchmarks requires justification.

Step 3: Extract Clinical Outcome Parameters

From the SOTA literature, identify the clinical outcome parameters that are commonly reported for the device type and clinical indication. These parameters become the benchmarks against which your device is compared in the CER.

Clinical outcome parameters are qualitative categories of measurable outcomes. Examples:

Step 4: Establish Safety and Performance Objectives

Convert the extracted clinical outcome parameters into quantitative safety and performance objectives. This involves calculating benchmark values from the SOTA literature.

For each clinical outcome parameter:

1. Collect all reported values from the SOTA literature
2. Weight each value by study quality and sample size
3. Calculate a weighted mean or range
4. Define the objective as the range of acceptable performance

Example — Drug-eluting stent for femoropopliteal lesions:

Document the calculation methodology:

• Sources included in the weighted calculation
• Weighting factors applied (study quality, sample size, relevance)
• Handling of outlier values
• Whether the objective represents a minimum threshold or a target range

Step 5: Assess SOTA in the Benefit-Risk Context

The SOTA review must also establish the benefit-risk context. Document:

• Known complications and adverse events associated with SOTA devices
• Severity and frequency of each risk
• How benefits weigh against risks for existing treatments
• Whether any risks are considered acceptable in current practice
• Areas where the SOTA shows room for improvement (unmet needs)

This analysis feeds directly into the benefit-risk assessment section of the CER and the risk management file (ISO 14971).

SOTA Must Come Before the CEP

The correct sequence for clinical evaluation is SOTA review first, then CEP, then CER. Mantra Systems, having conducted over 300 successful MDR evaluations, emphasizes that following this strict ordering ensures outputs of one process form the input into the next.

The SOTA review defines the "line in the sand" — the benchmarks against which your device will be measured. Without completing the SOTA first, the CEP cannot specify meaningful safety and performance objectives.

Important nuance from BSI's clinical evaluation guidance: The clinical outcome parameters in the CEP are initially "indicative" — they cannot be fully defined until the SOTA evaluation has been completed. During the initial CEP, several different outcome parameters may be proposed. The SOTA review then enables this indicative list to be refined and benchmarks to be established. This is the primary purpose of the SOTA evaluation: to define what "acceptable" looks like for a given patient population.

SOTA and the Clinical Evaluation Workflow

The SOTA review follows a defined sequence within the clinical evaluation process:

Clinical Evaluation Plan (CEP)
(with indicative parameters)
         │
         ▼
SOTA Literature Review ──────► Defines clinical context
         │                      Identifies benchmark devices
         │                      Establishes outcome parameters
         ▼                      Sets safety/performance objectives
Clinical Data Collection
(device-specific + equivalence data)
         │
         ▼
Data Appraisal & Analysis ─── Compared against SOTA benchmarks
         │
         ▼
CER Conclusions ────────────── Device meets/exceeds SOTA?
         │                      Gaps require PMCF?
         ▼
PMCF Planning ──────────────── SOTA gaps inform PMCF activities

The SOTA outputs flow into four downstream documents:

1. Clinical Evaluation Plan — Safety and performance objectives from SOTA
2. Risk Management File — Known risks from SOTA alternatives
3. CER Analysis Section — Benchmark comparison tables
4. PMCF Plan — Evidence gaps identified during SOTA review

Common Pitfalls

1. Confusing "SOTA" with "Best Available Technology"

SOTA is not the most technologically advanced solution — it is what is generally accepted as good practice. A Class IIa wound dressing is not benchmarked against the latest bioengineered skin substitute unless that substitute has become standard practice. Reference the ISO/IEC definition: "generally acknowledged as good practice in technology and medicine."

2. Using Outdated SOTA Data

SOTA must reflect current practice. Literature older than 5 years may no longer represent the state of the art if the field has evolved. Document your search period and justify the currency of your SOTA sources.

3. Cherry-Picking Favorable Comparators

Selecting only weak comparators to make your device look better is a common audit finding. Select benchmarks that represent genuine current clinical practice, even if they set a high performance bar.

4. Not Quantifying Benchmarks

Qualitative descriptions ("Device X shows good results") do not meet MDR expectations. Every SOTA benchmark must be quantified with specific values, ranges, and confidence intervals drawn from the literature.

5. Treating SOTA as a One-Time Exercise

SOTA changes over time as new devices enter the market, guidelines are updated, and clinical practice evolves. The SOTA review must be updated at each CER update cycle. What was SOTA five years ago may no longer be current.

6. Insufficient Breadth of SOTA Coverage

A SOTA review that only considers one type of comparator (e.g., only similar devices, not medical alternatives) may be incomplete. Notified Bodies expect manufacturers to consider the full treatment landscape.

SOTA for Specific Device Types

Software as a Medical Device (SaMD)

MDCG 2020-1 provides specific SOTA guidance for SaMD clinical evaluation:

• SOTA should cover both the clinical condition and the computational methodology
• Include performance of similar algorithms or analytical approaches
• Consider non-device software solutions that may represent current practice
• Address the pace of technological change in software (shorter SOTA refresh cycles)

Well-Established Technology (WET) Devices

MDCG 2020-6 defines well-established technology devices as having a "simple, common, and stable design, with well-known performance and safety across the generic device group, as well as a long history on the market." The December 2025 MDR reform proposal introduces a formal WET device definition. For WET devices:

• SOTA may rely more heavily on cumulative historical data and registry evidence
• Lower levels of evidence may be acceptable (per MDCG 2020-6 Appendix III)
• SOTA benchmarks can be based on long-term, real-world performance data

Orphan Medical Devices

MDCG 2024-10 provides adjusted expectations for SOTA reviews of orphan devices:

• Broader search scope may be needed due to limited device-specific literature
• SOTA may include treatments for similar conditions or related patient populations
• Absence of direct comparators should be explicitly documented and justified

Documenting the SOTA Review

A well-documented SOTA section should include:

1. Clinical background summary — Pathophysiology, epidemiology, current management
2. Literature search methodology — Databases, search terms, inclusion/exclusion criteria, PRISMA diagram
3. SOTA device summary table — Devices identified, key characteristics, market status
4. Clinical outcome parameters table — Parameters extracted from SOTA with supporting references
5. Safety and performance objectives — Quantified benchmarks with calculation methodology
6. Benefit-risk context — Known risks, benefits, and unmet needs
7. Gap analysis — Where the subject device's evidence may not fully address SOTA expectations
8. Conclusions — Summary of SOTA findings and implications for the clinical evaluation

The SOTA section should be written so that a qualified reviewer unfamiliar with the device can understand the clinical context and the benchmarks against which the device is being evaluated.