What is the difference between right-to-try and expanded access in clinical research?

When a person has a serious or life-threatening illness, has been through the approved treatment options for their condition without success, and cannot find or cannot join a clinical trial that fits their situation, two federal pathways in the United States exist for trying to obtain an investigational drug outside of a trial. One is called expanded access, also known as compassionate use. The other is called right-to-try. Both are for the same kind of situation. Both require the drug maker to agree. Neither guarantees the drug will help. The mechanics of each, however, are different in ways that affect who has to approve the request, what products qualify, and how much safety oversight is in place.

This blog explains what each pathway is, how they compare, and one question worth asking before either is considered.

What an investigational drug is, and why access is normally through a clinical trial

An investigational drug is a medicine that is being studied in clinical research and has not yet been approved by the U.S. Food and Drug Administration (FDA) for the condition being treated. The same term is used for investigational biologics (products like antibodies, cell therapies, and gene therapies) and, in a slightly different form, for investigational medical devices. Because safety and effectiveness are still being established, access to these products is regulated.

The primary way anyone gains access to an investigational drug is by enrolling in a clinical trial that is testing it. Trials use written eligibility criteria to protect participants from foreseeable harm and to make sure the data collected can actually answer the study's scientific question. Some patients, however, do not fit any open trial. They may live too far from a study site, they may have another medical condition that a trial excludes, or the trial they would fit may have already finished enrolling. For that group, the two pathways described below are what remain. A short primer on what a clinical trial actually is helps put both pathways in context: Clinical Trials Explained: Simple Guide for Beginners.

What expanded access is and how it works

Expanded access, often still called compassionate use in the media and in older documents, is the FDA-run pathway that has existed in some form since the 1980s. It was formalized in 2009. The FDA issued updated question-and-answer guidance for it in late 2025.

Expanded access is available when four conditions are all true: the patient has a serious or immediately life-threatening disease or condition; there is no comparable or satisfactory approved therapy for that condition; the patient cannot enroll in a clinical trial of the drug; and the potential benefit of the investigational drug justifies its potential risks. A fifth condition also applies from the drug developer's side: providing the drug this way must not interfere with the trials that could support the drug's eventual approval.

The request itself moves through a chain of approvals. The treating physician submits the request. The drug maker (the sponsor) must agree to provide the drug. The FDA authorizes the request under an investigational new drug application. An institutional review board, an independent ethics committee that reviews research involving people, also reviews the request to make sure appropriate protections are in place. In genuine emergencies, the FDA can authorize a request by phone in under 24 hours, with the ethics review completed shortly after. Across many years of data, the FDA has authorized the vast majority of expanded access requests, often within days.

Expanded access covers investigational drugs, biologics, and devices, and it applies whether the product is still in early testing or later stages of development. The pathway is intended for patient care, not for collecting research data, and it operates alongside the ongoing clinical trials of the same product. Informed consent is still part of the process, and a patient going through expanded access signs a consent form that describes the drug, its known risks, and what is unknown about it. Understanding how a consent form actually reads is useful preparation for either pathway: How to Read Your Informed Consent Form Before Joining a Clinical Trial.

What right-to-try is and how it works

Right-to-try is a federal law that was signed in May 2018. Its full name is the Trickett Wendler, Frank Mongiello, Jordan McLinn, and Matthew Bellina Right to Try Act, named for four patients who advocated for it. Before the federal law, most states had already passed their own right-to-try laws. The federal law creates a pathway that goes around the FDA. Under it, the treating physician can request an investigational drug directly from its manufacturer, and if the manufacturer agrees, the drug can be provided without FDA authorization and without ethics-committee review.

The eligibility conditions overlap with expanded access. The patient must have a life-threatening disease or condition, must have exhausted approved options, and must be unable to participate in a clinical trial of the drug. The patient also must give written informed consent. On the product side, right-to-try only covers investigational drugs and biologics, not medical devices, and the drug must have completed a Phase 1 trial (the first stage of human testing) and remain in active development.

Two features of the law are important to understand. First, right-to-try does not compel a drug maker to provide anything. The maker's agreement remains the pivot point in every case. Second, because the FDA and an ethics committee are not involved, the oversight built into expanded access is not part of the right-to-try process. Manufacturers must submit an annual summary report to the FDA about products provided under the law, but there is no case-by-case federal review before the drug is given. Documented use of the federal right-to-try pathway since 2018 has been limited compared with the volume of expanded access requests handled during the same years. For readers who are new to how clinical research is organized in the first place, a short overview of the volunteer's perspective is a useful anchor: Clinical Trial Volunteers Guide: Your First Step Into Clinical Trials.

How the two pathways compare on the points that matter

The clearest way to see the difference is to hold the two pathways next to each other across the questions a patient and a treating physician would actually ask.

Who has to say yes

Expanded access requires the drug maker, the FDA, an ethics committee, and the treating physician. Right-to-try requires the drug maker and the treating physician. In both cases, the drug maker's agreement is decisive: no company can be forced to provide an investigational drug outside a trial, and companies have their own criteria for when they will and will not do so.

What products qualify

Expanded access covers drugs, biologics, and medical devices at any stage of development. Right-to-try covers only drugs and biologics, and only after the product has completed a Phase 1 trial and is still in active development. If the product a patient is interested in is a device, or if it has not yet completed Phase 1, right-to-try does not apply.

Speed

Expanded access is often faster than its reputation suggests. Standard requests can be reviewed in days, and emergency requests can be authorized by phone in under 24 hours. Right-to-try skips the FDA step entirely, so the timeline is set by how quickly the drug maker responds and how quickly the physician and the manufacturer can arrange the logistics. Practical speed depends heavily on which manufacturer is involved.

Safety oversight

Under expanded access, the FDA reviews the request, an ethics committee reviews the plan for the patient, and adverse events are reported through the same investigational new drug framework used for clinical trials. Under right-to-try, that federal review is not part of the process. The treating physician and the drug maker are responsible for how the drug is given and monitored. This is a meaningful trade-off, and it is worth naming clearly when either pathway is being considered.

Cost

Under both pathways, drug makers are permitted to charge for the cost of providing an investigational drug, though many do not. Health insurance often does not cover investigational products or the visits associated with them, and neither pathway changes that. Any patient considering either route should ask about cost early in the conversation.

Both pathways also require, as a condition of use, that the patient cannot enroll in a clinical trial. That condition sits behind everything else. Sometimes it is straightforward. Sometimes it is worth a second look, because eligibility is more nuanced than a single yes-or-no answer: Eligibility Explained: Why Not Everyone Qualifies for a Trial.

One question worth asking before either pathway is considered

Both expanded access and right-to-try are built on the assumption that no clinical trial is available. That assumption is worth testing before either route is pursued. Clinical trials are the primary path for accessing investigational drugs, and they carry the safety oversight both pathways were designed to preserve.

Eligibility criteria vary widely from trial to trial, and a person who does not fit one trial may fit another testing a similar drug or the same mechanism. New trial sites open and enrollment criteria sometimes broaden mid-study. A treating physician who checked for trials months ago may not have seen studies that have opened since. A structured search that looks across multiple current studies can sometimes surface options that a general search misses.

DecenTrialz is a platform that helps people find clinical trials they may be eligible for. A person shares some basic information about themselves and their condition, gets matched to studies that could fit, and a nurse walks them through what each study involves before they decide whether to move forward. The research team running any study makes the final eligibility and enrollment decisions. You can start a search at decentrialz.com. If a trial does not fit after that search, the conversation with the treating physician about expanded access or right-to-try becomes a better-informed one, because it has a clear answer to the question the pathways themselves ask first. For a walk-through of how a search on the platform actually works: DecenTrialz Explained: How to Search, Read, and Apply for Clinical Trials.

What to talk about with your doctor

Both pathways begin with the treating physician. Neither begins with the FDA or the drug maker directly. A useful conversation with the doctor typically covers a short list of questions.

First, confirm the trial question. Has the patient been screened for current trials of the drug or of similar drugs, and has the eligibility answer been checked recently rather than months ago? Second, if a trial genuinely does not fit, ask whether the doctor has requested a drug through expanded access or right-to-try before, and which pathway makes sense for the specific product involved. Some drugs are only available through one route or the other in practice, based on the manufacturer's policy. Third, ask about the drug maker's agreement, because that agreement is the pivot point in either case. Fourth, ask what the drug will cost, how it will be given, and what monitoring will be in place. Fifth, and important, understand that neither pathway guarantees benefit, and that both provide access, not certainty.

A clinical trial, when one fits, remains the primary way to access an investigational drug and the pathway with the most safety oversight built in. You can begin a search at decentrialz.com. The research team running any study makes the final eligibility and enrollment decisions, and a nurse-led conversation before referral helps a person understand what each study involves before any decision is made.