The decision to join a clinical trial is deeply personal. Most trial resources focus on either cheerleading ("help advance science!") or logistics ("here's how to register on ClinicalTrials.gov"). What gets skipped over are the real trade-offs that affect your daily life. Taking time off work, managing a washout period without your current medication, traveling to a distant site weekly, accepting a 50-50 chance you receive placebo. These considerations matter.
We wrote this guide to give you a structured way to think through whether a particular trial makes sense for you. Not whether trials exist, or how to search for them.
Understanding Placebo Probability
Many trials use randomization, which means you might receive the study drug or a placebo. The exact odds depend on the trial's randomization ratio, which is always disclosed in the protocol.
If the protocol says 1-to-1 randomization, you need to accept a 50-50 chance. Some trials disclose the ratio in the title on ClinicalTrials.gov. Others require reading the full protocol.
For rare diseases, placebo probability becomes especially significant when the disease is progressive and time off treatment is costly. If you have Friedreich ataxia and you're enrolled in a 1-to-1 randomized trial, 6 months on placebo might mean real decline in function. That's a legitimate concern to weigh.
Travel and Time Burden
Rare disease patients travel an average of 135 miles to reach a clinical trial site, roughly double the 67-mile average across all trials (Greenphire, 2022). With fewer sites running trials for conditions like Friedreich ataxia or Pompe disease, that distance grows fast. Most trials don't cover travel.
Calculate the actual time commitment before you enroll. Screening visits typically run 2 to 4 hours and determine your eligibility. Treatment visits depend on the drug and disease. Monitoring visits check your safety. Some trials require monthly bloodwork, others every 2 weeks.
Factor in driving, parking, waiting, and the appointment itself. If you live in rural Wyoming and the trial site is 4 hours away, that's 8 hours of driving per visit plus the appointment. Over a 52-week trial with biweekly visits, you're looking at roughly 450 hours of travel time.
A few trials offer travel assistance or cover lodging. Many don't. Ask the research coordinator early whether the trial has a travel fund.
Medication Washout Periods
A washout period means stopping your current medication before starting the study drug. This happens because researchers need to measure the study drug's effect without interference from other treatments.
Washout periods typically run 2 to 6 weeks. For someone taking a maintenance medication for a chronic rare disease, stopping treatment poses real risk. A person with SMA on nusinersen needs regular spinal injections every 4 months. Skipping 6 weeks could mean muscle weakness progresses during the washout window.
This is a conversation to have with your own physician before enrolling. Your doctor can tell you whether a specific washout period is safe for you, and whether the disease's trajectory during washout is predictable or dangerous.
Open-Label Extension Access
One of the most important questions rarely gets asked until too late. Can you keep taking this drug after the trial ends?
In a review of FDA and EMA approvals, 12 of 13 drugs that relied on expanded access data for regulatory submission had orphan designation (Polak et al., 2020). Rare disease patients disproportionately depend on trial access for continued treatment.
Some trials have open-label extensions, where patients who benefit continue receiving the drug after the main trial ends. Others don't. Some sponsors commit to expanded access programs if the drug is beneficial but not yet approved. Others make no commitment.
If you're enrolling in a trial for Pompe disease or Dravet syndrome hoping for access to a novel therapy, ask whether an open-label extension exists or whether the sponsor has committed to expanded access. This shouldn't be a surprise after the trial concludes.
Financial Costs and Insurance
Study-related procedures are usually covered by the trial sponsor. Your blood draws, imaging, genetic testing, and investigational drug are generally paid for.
What often isn't covered is the rest. Standard-of-care costs your insurance would normally pay, travel expenses, parking, meals, lodging, lost wages while you're at appointments, or caregiver wages while someone else drives you to visits. A 2021 study in The Oncologist found that 64% of early-phase trial participants reported unanticipated nonmedical expenses, and 55% reported unanticipated medical expenses (Huey et al., PMC8265355).
If you take multiple medications, ask whether the trial covers or requires stopping them. Insurance gaps between the trial's coverage and your plan's coverage can leave you paying hundreds monthly.
Deliberation Time Is Your Right
You are allowed to take time with this decision. Some patients decide in days. Others take weeks. Taking a month is normal. Asking for a second opinion from another physician is normal. Requesting the full protocol, not just the summary on ClinicalTrials.gov, is your right.
No legitimate clinical trial pressures you into an immediate decision. If a recruiter or site coordinator tells you the deadline to enroll is urgent, ask whether it's a real regulatory deadline or a recruitment preference. Usually it's the latter.
Slow down. Read the protocol. Talk to your doctor. Take notes on the factors above. You're allowed to say no.
This Is Part of a Series
This post is the first in our 4-part series on clinical trial participation. Next, we cover how to talk to your doctor about clinical trials, including why physicians often don't bring up trials and what to do when they disagree.
Later in the series, we walk through what questions to ask before joining and what happens after you express interest. You can also read the full series overview.