Investigator-initiated trials (IITs) play a critical role in advancing clinical research by allowing investigators to pursue important scientific questions beyond traditional sponsor-led studies. They’ve become an increasingly important model for answering clinically meaningful questions that may not be addressed otherwise.
However, conducting an IIT requires more than a compelling research question. Investigators must also consider study sponsorship, funding, regulatory and institutional review board (IRB) requirements, operational planning, participant recruitment, data management, and reporting. This FAQ answers common questions about how investigator-initiated studies work and how investigators can plan and manage them successfully.
1. What are investigator-initiated trials?
IITs are clinical studies conceived, designed, and led by an investigator rather than a pharmaceutical, biotechnology, or medical device company.
The principal investigator (PI) develops the scientific question and protocol and often serves as the sponsor-investigator. Industry organizations, government agencies, foundations, or research institutions may still provide funding, study drugs, devices, or other support.
IITs commonly explore new indications, dosing strategies, real-world evidence, or other investigator-generated scientific questions. (For more background, read this beginner’s guide to IITs.)
2. How do investigator-initiated trials differ from sponsor-led clinical trials?
The primary difference is who assumes responsibility for designing, conducting, overseeing, and reporting the study.
| Category | Investigator-initiated trial | Sponsor-led clinical trial |
| Leadership and study design | The investigator conceives, designs, sponsors, and leads the study. | The sponsor designs and oversees the study, while investigators conduct it according to the protocol. |
| Purpose and funding | Addresses investigator-driven scientific questions and may be funded by government agencies, foundations, institutions, or industry grants. | Supports product development and regulatory approval and is funded by the sponsoring company. |
| Regulatory and operational responsibilities | The sponsor-investigator is responsible for regulatory compliance, IRB submissions, safety reporting, monitoring, and study oversight, often with institutional or external support. | The sponsor manages regulatory requirements, safety reporting, monitoring, and overall trial operations. |
| Data and publications | Investigators typically retain greater control over study data and publication, subject to funding agreements. | Sponsors generally own the study data and establish publication review requirements. |
| Typical setting | Academic medical centers, health systems, and independent research institutions. | Multisite commercial clinical trials sponsored by pharmaceutical, biotechnology, or medical device companies. |
3. Who can conduct an investigator-initiated trial?
Qualified investigators affiliated with hospitals, academic medical centers, health systems, or research institutions may conduct IITs if they have the necessary expertise and institutional support.
Investigators need appropriate clinical and scientific qualifications, sufficient research infrastructure, and an experienced study team capable of supporting day-to-day study execution. Sponsor-investigators must also be prepared to fulfill responsibilities related to regulatory compliance, participant protection, safety oversight, monitoring, data management, and recordkeeping.
4. Who funds investigator-initiated trials?
IITs may be funded by government agencies, nonprofit organizations, academic institutions, pharmaceutical companies, or institutional research funds.
Federal funding may come from agencies such as the National Institutes of Health (NIH), National Cancer Institute (NCI), or National Heart, Lung, and Blood Institute (NHLBI). Other sources include industry grants and study support, investigator grants, foundation funding, and internal institutional funding.
Funding does not necessarily determine study sponsorship. A company may provide financial support, a drug, or a device without assuming the sponsor’s regulatory responsibilities.
5. Why do investigators choose to conduct investigator-initiated trials?
IITs allow investigators to pursue clinically important research questions that may not align with commercial development priorities.
Investigators may use these studies to explore new indications, optimize treatment strategies, evaluate real-world outcomes, improve standards of care, or generate preliminary evidence for future research. This flexibility makes investigator-sponsored research an important complement to sponsor-led development programs.
6. What are the regulatory responsibilities of a sponsor-investigator?
Sponsor-investigators assume both investigator and sponsor responsibilities under applicable Food and Drug Administration (FDA) regulations.
Depending on the study, these responsibilities may include obtaining and maintaining an investigational new drug application (IND) or investigational device exemption (IDE), overseeing protocol compliance, monitoring the study, maintaining required records, reporting safety information, and submitting required reports to the FDA. Beyond completing individual regulatory tasks, the sponsor-investigator must maintain effective oversight of the study throughout its life cycle. The specific obligations depend on the study design, intervention, and regulatory status.
7. Do investigator-initiated trials require IRB approval?
Yes. Like other human subjects research, IITs generally require IRB review and approval before participant enrollment.
The IRB reviews the protocol, informed consent materials, recruitment plans, and safeguards intended to protect participants. After approval, investigators must submit amendments, reportable events, and continuing review materials when applicable. Depending on the study’s structure and participating institutions, oversight may involve a local or central IRB.
8. What are the biggest challenges of investigator-initiated research?
Investigators often face operational, financial, regulatory, and administrative challenges while balancing research with clinical responsibilities.
Common challenges include limited staff, budget constraints, participant recruitment, regulatory complexity, data management, monitoring, maintaining compliance, and time management. These pressures may become especially significant when an investigator-initiated study expands beyond one site.
9. What operational support helps investigator-initiated trials succeed?
Successful IITs typically rely on experienced partners and institutional resources to manage complex research activities.
Support may include IRB services, regulatory consulting, protocol development, study startup, research compliance, monitoring, data management, and technology platforms. Investigators should determine early which capabilities are available internally and where external expertise may be needed.
10. How should investigators develop a strong IIT protocol?
A well-designed protocol provides the scientific and operational foundation for a successful study.
The protocol should establish clear objectives, appropriate endpoints, well-defined eligibility criteria, statistical considerations, safety monitoring procedures, and realistic operational plans. Early feasibility assessments can help determine whether the proposed population, procedures, timelines, staffing, and resources support successful execution.
11. How can investigators improve participant recruitment and retention?
Recruitment strategies should be realistic, participant-centered, and integrated into study planning from the beginning.
Investigators should assess whether the eligible population is accessible, plan outreach to diverse participant populations, engage participating sites early, and develop clear participant communications. Retention planning should also identify opportunities to reduce avoidable burdens associated with study visits, procedures, travel, and participation while maintaining scientific rigor and participant safety.
12. What common mistakes delay investigator-initiated trials?
Many delays result from insufficient planning rather than scientific challenges.
Incomplete protocols, unrealistic budgets, delayed regulatory submissions, poor feasibility assessments, missing operational plans, underestimated staffing needs, and late contract negotiations can all slow study startup. Addressing these dependencies before submission can reduce avoidable revisions and support more reliable timelines.
13. How can investigators set an IIT up for success?
Early planning, strong governance, and experienced operational support significantly improve the likelihood of successful study execution.
Investigators should engage stakeholders early, build realistic timelines, secure funding, establish quality-management plans, engage the IRB early, and develop monitoring strategies. They should also define responsibilities across the study team, use experienced research partners where needed, and plan for publication and data sharing from the outset. (For more guidance, learn how to set yourself up for success during IITs.)
14. What happens after an investigator-initiated trial is completed?
Investigators remain responsible for study closeout, data analysis, reporting, and dissemination of findings.
Closeout activities may include reconciling study records, submitting final reports, meeting applicable ClinicalTrials.gov reporting requirements, archiving study data and essential documents, publishing findings, and sharing results with participants when appropriate. The evidence generated may also create opportunities for future research.
15. What are the most important takeaways about investigator-initiated trials?
IITs empower investigators to answer meaningful clinical questions while requiring careful planning, strong regulatory oversight, and effective operational support.
Unlike sponsor-led trials, IITs often place both sponsor and investigator responsibilities on the sponsor-investigator. Protecting participants, maintaining regulatory compliance, establishing clear governance, and developing realistic operational plans are therefore essential. Investigators should use institutional resources and experienced research partners when they need additional expertise or operational capacity.
Advancing clinical research through investigator-initiated trials
IITs play an essential role in advancing clinical research by enabling investigators to pursue innovative scientific questions. Successful ones require thoughtful planning, strong governance, regulatory compliance, participant protections, and collaboration with experienced research partners. That breadth of responsibility makes it essential to identify and address capability gaps before they interfere with the study. By securing the right support early, investigators can build a stronger foundation for the full study life cycle.
Want to learn more? Check out Advarra’s resources on IITs, IRB review, and clinical research operations, or contact us to ask an expert a specific question.
