Starting a clinical trial requires moving through a series of regulatory, scientific, and logistical steps before a single participant can be enrolled. The process typically takes months of preparation, beginning with preclinical evidence and ending with regulatory clearance and site activation. Whether you’re a researcher at an academic institution or part of a pharmaceutical company, the core pathway is the same: build the scientific foundation, design the protocol, secure ethical and regulatory approval, set up your sites, and register the trial publicly.
Build the Preclinical Foundation
Before any drug or treatment can be tested in humans, you need preclinical data showing it’s reasonably safe to try. This means conducting animal pharmacology and toxicology studies that demonstrate how the compound behaves in a living system, what doses cause harm, and what the safety margins look like. These studies form the backbone of your regulatory submission and give reviewers confidence that human participants won’t face unreasonable risk.
You’ll also need detailed manufacturing information: what the drug is made of, how it’s produced, how stable it is over time, and what quality controls are in place. Regulators evaluate this to confirm you can produce consistent batches. If your compound has been used in humans before, perhaps in another country, that data should be compiled as well.
All of this preclinical and manufacturing evidence gets organized into what’s called an Investigator’s Brochure. This document summarizes your nonclinical pharmacology, toxicology, and metabolism data, along with any known effects in humans such as dose response, safety profile, and efficacy signals from earlier work. The Investigator’s Brochure is what clinical investigators will rely on to understand the treatment they’re administering.
Design the Protocol
The protocol is your trial’s blueprint. It spells out exactly what will happen, to whom, and how the results will be measured. A well-designed protocol covers several key areas: the scientific rationale for the study, the specific question you’re trying to answer, how you’ll select participants, what treatments they’ll receive, what measurements you’ll collect, and how you’ll analyze the data.
Participant selection criteria are among the most consequential decisions you’ll make. You define who is eligible (inclusion criteria) and who is not (exclusion criteria) based on factors like age, diagnosis, medical history, and current medications. These criteria directly affect how quickly you can enroll, how generalizable your results will be, and how safe the trial is for participants.
Your protocol also needs to specify primary endpoints, which are the main outcomes that will determine whether the treatment works. A cancer trial might measure tumor shrinkage or survival time. A pain trial might use standardized pain scales. Choosing the right endpoint and the right statistical approach to analyze it is critical, because regulators will judge your results against these predefined benchmarks. The protocol should also describe how long participants will be followed, what safety monitoring will be in place, and what happens if a participant experiences a serious side effect.
Submit the IND Application
In the United States, you cannot begin testing a new drug in humans without filing an Investigational New Drug (IND) application with the FDA. The IND pulls together three broad categories of information: your preclinical safety data, your manufacturing details, and your clinical protocols along with investigator qualifications.
The investigator section is particularly important. You need to show that the physicians overseeing the trial are qualified, that they’ll obtain informed consent from every participant, and that an Institutional Review Board (IRB) will review the study. Once the IND is submitted, you must wait 30 calendar days before enrolling anyone. During that window, the FDA reviews your submission to confirm that participants won’t be exposed to unreasonable risk. If the agency has serious safety concerns, it can place a clinical hold that prevents the trial from starting until those concerns are resolved.
Secure IRB Approval
Every clinical trial involving human participants requires approval from an Institutional Review Board, an independent committee that evaluates the ethical dimensions of your study. The IRB’s job is to protect participants, and federal regulations lay out seven specific criteria they must verify before granting approval.
The board confirms that risks are minimized through sound research design, that those remaining risks are reasonable relative to the potential benefits, and that participant selection is equitable. They pay particular attention to studies involving vulnerable populations such as children, prisoners, pregnant women, or people with cognitive disabilities. The IRB also verifies that informed consent will be properly obtained and documented, that there are adequate provisions for monitoring participant safety during the trial, and that privacy and data confidentiality protections are in place.
To get IRB approval, you’ll submit your full research proposal, scientific evaluations, sample consent documents, and your protocol. Once the trial is running, you’re required to submit progress reports and immediately report any injuries to participants. The IRB can suspend or terminate approval at any time if it determines the study is no longer meeting its safety or ethical standards.
Select and Prepare Your Research Sites
Choosing the right trial sites is one of the biggest operational decisions you’ll face. A site feasibility assessment evaluates whether a location has the right combination of qualified staff, appropriate facilities, and access to the patient population you need.
On the personnel side, you’re looking at whether the principal investigator and study coordinator have experience with clinical research, the therapeutic area, and the specific patient population. You need to confirm they have enough time to conduct the study, attend monitoring visits, and participate in study meetings. A common pitfall is selecting investigators who are overcommitted with other trials and can’t dedicate the attention your study requires.
Facilities matter just as much. The site needs adequate examination and procedure rooms, access to emergency equipment, properly maintained clinical equipment specific to your protocol, secure storage for study records, and space for data entry. If laboratory work is involved, you’ll need to verify whether the site uses a central lab or a local one, whether that lab is certified for the procedures your study requires, and whether specimen storage meets your standards for temperature monitoring, security, and backup power.
Patient access is the third pillar. You want to know what percentage of the site’s prior studies met enrollment goals and timelines. Consider whether the site plans to advertise for participants, what languages are spoken in the surrounding community, and whether the investigators can communicate effectively with that community. Competing trials enrolling the same patient population at the same site can significantly slow your recruitment.
Set Up Data Management Systems
Clinical trials generate enormous amounts of data, and the systems you use to capture and manage that data must meet strict regulatory standards. Good Clinical Practice guidelines require that any electronic system used in a trial be validated, meaning it’s been tested and documented to work as intended. You need standard operating procedures for using the system, and every change to the data must be tracked through an audit trail that records who changed what and when.
In the U.S., FDA regulations on electronic records and electronic signatures add additional requirements around data security and system access controls. Your data management infrastructure needs to ensure privacy, maintain backup systems, and produce reliable, tamper-evident records that can withstand regulatory scrutiny during an audit.
Register the Trial Publicly
Federal law requires that applicable clinical trials be registered on ClinicalTrials.gov within 21 days of enrolling the first participant. Registration includes details about the study’s purpose, design, eligibility criteria, locations, and contact information. This isn’t optional. Failure to register or to submit required results information is a violation of federal law. The FDA can pursue civil monetary penalties against the responsible party, and for trials funded by NIH or FDA grants, noncompliance can result in withheld funding for both current and future grants.
Understand the Trial Phases
Clinical trials proceed through distinct phases, each with a different purpose and scale. Phase I trials enroll a small group, typically 20 to 80 people, and focus primarily on safety. The goal is to identify side effects and determine a safe dosage range. These participants are often healthy volunteers rather than patients with the target condition.
Phase II trials expand to 100 to 300 participants and shift the focus toward effectiveness. Does the treatment actually do what it’s supposed to do? Safety monitoring continues, but the primary question becomes whether the drug works well enough to justify larger studies.
Phase III trials are the large-scale confirmatory studies, enrolling 1,000 to 3,000 participants. These trials compare the new treatment against existing standard therapies or placebo, confirm effectiveness across a broader population, and generate the safety and efficacy data needed for regulatory approval. Phase III results are typically what the FDA reviews when deciding whether to approve a drug for market.
Phase IV trials happen after approval, tracking the drug’s performance in the general population. These studies look for rare side effects that might not have appeared in earlier phases and gather additional information about long-term benefits and optimal use.
Timeline and Practical Expectations
From the earliest preclinical work to the first enrolled participant, the startup process for a clinical trial commonly takes 12 to 18 months or longer, depending on the complexity of the treatment and the regulatory landscape. The IND review alone requires a minimum 30-day waiting period, and IRB review can take several weeks to several months depending on the board’s meeting schedule and whether revisions are requested. Site activation, which includes contracting, training, and equipment verification, adds additional time.
Budget planning should account for preclinical studies, manufacturing, regulatory filing fees, IRB fees, site payments, investigator compensation, data management systems, monitoring visits, insurance, and participant-related costs like travel reimbursement. Many trials also require a Data Safety Monitoring Board, an independent group that periodically reviews accumulating safety data and can recommend stopping the trial early if safety signals emerge or if the treatment is clearly effective or ineffective.