Clinical Trial Monitoring in 2026: On-Site, Remote and Centralized Monitoring Explained

Clinical trial monitoring has evolved substantially.

Traditionally, monitoring was strongly associated with Clinical Research Associates (CRAs) travelling to investigative sites, reviewing source documents, checking Case Report Forms and confirming compliance with the protocol.

Those activities remain important.

But modern clinical trials generate information through increasingly diverse systems and settings.

Clinical data may originate from hospitals, central laboratories, imaging facilities, electronic patient-reported outcome systems, wearable devices and decentralized trial activities.

At the same time, studies may operate across multiple countries and hundreds of sites.

This raises an important question:

How can sponsors monitor clinical trials effectively without applying the same level of review to every data point, process and site?

The answer lies in combining appropriate monitoring methods within a risk-based strategy.

ICH E6(R3) recognizes on-site and remote investigator-site monitoring alongside centralized monitoring, with the monitoring approach tailored to risks affecting participant safety and reliable trial results [1].

What Is Clinical Trial Monitoring?

Clinical trial monitoring is a quality-control activity that helps determine whether trial conduct is appropriate and whether important trial processes and data are reliable.

Monitoring contributes to three broad objectives:

Participant protection

Protocol and regulatory compliance

Reliability of trial results

However, monitoring should not be confused with auditing.

Monitoring is generally part of ongoing trial oversight.

Auditing provides an independent and systematic evaluation of trial-related activities and records against applicable requirements.

Both contribute to quality, but they serve different functions.

1. On-Site Monitoring: Understanding What Happens at the Site

On-site monitoring involves reviewing relevant trial activities at the investigative site.

Depending on the protocol and monitoring plan, activities may include:

• Reviewing informed consent documentation
• Evaluating participant eligibility
• Reviewing critical source records
• Checking investigational product accountability
• Assessing protocol compliance
• Reviewing safety documentation
• Discussing outstanding issues
• Evaluating site processes
• Confirming that corrective actions are implemented

On-site visits also allow CRAs to understand operational conditions that may not be obvious from a database.

For example, a site may show delayed data entry because its research team is understaffed.

A dashboard may reveal the delay.

An on-site discussion may reveal its cause.

When Is On-Site Monitoring Particularly Valuable?

It can be valuable when:

• Critical site processes require direct observation.
• Investigational product handling needs physical review.
• Repeated important deviations have occurred.
• Source records cannot be reviewed appropriately remotely.
• Site infrastructure or processes require assessment.
• Serious quality concerns require investigation.

The objective is not to visit a site merely because a fixed interval has elapsed.

It is to perform monitoring activities that address relevant study risks.

2. Remote Monitoring: Oversight Without Physical Presence

Remote monitoring allows certain monitoring activities to be conducted without travelling to the site.

Depending on applicable requirements, security arrangements and authorized access, this may involve:

• Reviewing electronic trial records
• Reviewing EDC data
• Conducting virtual site discussions
• Reviewing outstanding queries
• Following up monitoring findings
• Reviewing training and essential documentation
• Assessing selected source information through approved secure access

Remote monitoring can improve operational flexibility.

It may reduce travel burden and support more timely follow-up.

But remote monitoring is not automatically suitable for every activity.

Sponsors must consider:

Data privacy

Information security

Site permissions

Source record accessibility

Participant confidentiality

System suitability

A remote process that creates uncontrolled copies of sensitive medical records is not a successful monitoring strategy.

3. Centralized Monitoring: Seeing Patterns Across the Study

Centralized monitoring examines accumulated study data to identify potential problems, trends and unusual patterns.

It is typically performed by appropriately qualified and trained personnel, which may include clinical, medical, data management and statistical professionals.

Unlike site-level monitoring, centralized monitoring can examine information across multiple sites simultaneously.

Consider a multicountry trial involving 50 investigative sites.

Most sites report adverse events in a substantial proportion of participants.

Three sites report almost none.

This does not automatically demonstrate misconduct or under-reporting.

But it may justify further assessment.

Centralized monitoring can also identify:

• Unusual recruitment patterns
• Unexpected data distributions
• Missing critical assessments
• Repeated visit-window deviations
• Delayed data entry
• Inconsistent laboratory findings
• Potential protocol noncompliance
• Site-specific quality trends

ICH E6(R3) recognizes that centralized monitoring can complement, reduce the extent or frequency of, or in suitable circumstances be used without investigator-site monitoring [1].

The appropriate combination depends on study risk and the information available.

4. How the Three Monitoring Approaches Differ

Monitoring method	Primary strength	Example
On-site	Direct evaluation of site activities and processes	Reviewing investigational product storage and accountability
Remote	Timely site-level review without physical travel	Reviewing critical documentation through authorized secure access
Centralized	Cross-site pattern detection and trend analysis	Identifying sites with unusual safety-reporting or missing-data patterns

These approaches are complementary rather than mutually exclusive.

A centralized review may identify a potential issue.

Remote monitoring may help clarify it.

An on-site visit may then be required to investigate or resolve it.

The monitoring method should follow the risk—not the other way around.

5. Risk-Based Monitoring Starts With Critical-to-Quality Factors

Before developing a monitoring plan, sponsors should identify what is most important to the trial.

Examples include:

• Valid informed consent
• Correct participant eligibility
• Accurate primary endpoint assessment
• Appropriate investigational treatment administration
• Timely reporting of important safety events
• Maintenance of blinding
• Reliable randomization
• Completeness of critical data

These are examples of potential Critical-to-Quality factors.

The actual factors should be determined for each study.

A Phase I dose-escalation oncology trial may require intensive oversight of dose-limiting toxicity assessments.

A large pragmatic study may have different monitoring priorities.

ICH E8(R1) and E6(R3) support this risk-proportionate approach [1,2].

6. Source Data Verification Is Not the Entire Purpose of Monitoring

Source Data Verification (SDV) involves comparing reported data against the relevant source records.

It can help identify discrepancies.

However, checking every data field against source records does not necessarily prevent all important trial-quality problems.

For example, complete SDV may not reveal:

• Poorly designed eligibility criteria
• Systematic endpoint misinterpretation
• Inadequate adverse-event identification
• Inappropriate participant selection
• A flawed laboratory process
• A recurring operational problem across sites

Monitoring should therefore evaluate both important data and the processes that generate them.

Targeted SDV, source data review, centralized analysis and site-process evaluation may all contribute to an appropriate monitoring strategy.

7. The Monitoring Plan Is a Strategic Document

A monitoring plan should describe more than visit frequency.

It should explain:

• The monitoring strategy
• Relevant study risks
• Critical data and processes
• Monitoring methods
• Roles and responsibilities
• Monitoring activities
• Escalation arrangements
• Documentation expectations
• How monitoring may change during the trial

ICH E6(R3) emphasizes that the plan should be tailored to risks affecting participant safety, data quality and reliability of trial results [1].

This means the monitoring plan should be justified by the study's risk profile.

8. Monitoring Intensity Should Change When Risks Change

A risk-based monitoring strategy is not static.

Consider a site that initially performs well.

Later, the study team observes:

• Increasing eligibility deviations
• Repeated delayed SAE reporting
• Growing numbers of unresolved queries
• Delayed monitoring action closure
• High CRC turnover

These signals may justify additional review or monitoring.

Conversely, where justified by the risk assessment and accumulated evidence, some activities may require less intensive oversight.

The goal is proportionality.

Not automatic reduction.

9. Key Risk Indicators Help Prioritize Attention

Key Risk Indicators (KRIs) can help sponsors detect changes in operational or quality risk.

Examples include:

Eligibility deviations

SAE reporting timeliness

Missing primary endpoint data

Query aging

Participant discontinuations

Data-entry delays

Unusual adverse-event reporting

Monitoring finding recurrence

But KRIs require interpretation.

A site with no reported adverse events is not necessarily the safest site.

A site with many protocol deviations may be reporting minor issues more transparently than another site.

Metrics should generate questions and guide investigation.

They should not replace qualified clinical judgment.

10. The CRA's Role Is Evolving

Modern CRAs need more than document-review skills.

They increasingly need to understand:

• Risk-based monitoring
• Clinical data trends
• Site performance
• Protocol-specific critical processes
• Centralized monitoring findings
• Technology platforms
• Safety escalation
• Root cause analysis
• Corrective action follow-up
• Cross-functional communication

The CRA remains an important link between the investigative site and the sponsor or CRO.

But effective monitoring increasingly depends on collaboration with:

Clinical Operations

Data Management

Medical Monitoring

Pharmacovigilance

Biostatistics

Quality Assurance

Monitoring is no longer best understood as an isolated site-visit function.

11. Technology Supports Monitoring-but Does Not Replace Judgment

Modern platforms can consolidate information from EDC, CTMS, laboratory systems, safety databases and other sources.

Automated alerts and statistical methods may help identify emerging problems.

However, an unusual data pattern is not automatically evidence of noncompliance.

It may reflect:

• Different patient characteristics
• Site-specific clinical practice
• Data-entry conventions
• Small sample sizes
• Random variation
• Genuine process deficiencies

Qualified professionals must interpret the signal and decide what action is appropriate.

12. What Should Sponsors Ask About Their Monitoring Strategy?

Sponsors should be able to answer:

1. Which participant-safety and data-quality risks are most important?
2. How does the monitoring plan address those risks?
3. Which activities require on-site review?
4. Which activities can be performed remotely?
5. What centralized monitoring analyses are being performed?
6. Who reviews the resulting signals?
7. What triggers additional monitoring or escalation?
8. How are findings resolved and documented?
9. How is monitoring effectiveness evaluated?
10. Does the strategy remain appropriate as the trial evolves?

These questions help distinguish a genuinely risk-based approach from a traditional monitoring schedule with fewer site visits.

The Agile Clinical Trendz Perspective

At Agile Clinical Trendz, we believe monitoring should connect local site understanding with centralized clinical and data intelligence.

Effective monitoring requires:

Experienced CRAs

Appropriate site engagement

Reliable clinical data

Risk-based planning

Cross-functional review

Clear escalation

Documented follow-up

For sponsors, the most important question is not:

How many monitoring visits were completed?

It is:

Did our monitoring approach identify and address the risks that mattered most?

Because successful monitoring is not defined by the volume of records reviewed or the number of visits conducted.

It is defined by how effectively the monitoring strategy supports participant protection and reliable clinical evidence.

References

1. International Council for Harmonisation. ICH E6(R3): Guideline for Good Clinical Practice. 2025. Section 3.11, Monitoring.
2. International Council for Harmonisation. ICH E8(R1): General Considerations for Clinical Studies. 2021.
3. U.S. Food and Drug Administration. A Risk-Based Approach to Monitoring of Clinical Investigations: Questions and Answers. Final Guidance. April 2023.
4. U.S. Food and Drug Administration. Oversight of Clinical Investigations—A Risk-Based Approach to Monitoring. Final Guidance. August 2013.