Clinical trials are not risk-free, and nobody should tell you they are. What they are is carefully reviewed and heavily monitored. Before a clinical trial can begin in Australia, it must go through an independent ethics review and meet regulatory requirements designed to protect the rights, safety and wellbeing of participants. Researchers must also follow strict standards for how the study is conducted and continue monitoring participant safety throughout the trial.
But the honest answer to "Are clinical trials safe?" has two sides.
There are safeguards in place to reduce and manage risk. But some risk and uncertainty are an unavoidable part of clinical research, and understanding those risks is an important part of deciding whether participation is right for you.
What actually protects you in a clinical trial?
Seven layers, and they're worth knowing by name so you can check each one:
- Independent ethics review. A human research ethics committee (HREC) reviews the protocol, the consent form and the risk-benefit balance before a single participant is enrolled. HRECs include laypeople, not just doctors, and they're independent of the company running the trial. Approval can be withdrawn.
- Regulatory oversight. Trials of unapproved therapeutic goods in Australia run under the TGA's Clinical Trial Notification or Clinical Trial Approval schemes. The regulator knows the trial exists and can intervene.
- Good clinical practice (GCP). The ICH E6 guideline for good clinical practice is the international standard Australian trials follow. Its first principle is that the rights, safety and wellbeing of participants prevail over the interests of science. That's not a slogan. It's the sentence auditors hold sites to.
- Informed consent as a process. Not a signature. You're entitled to time, plain-language explanation, answers, and re-consent if new safety information emerges mid-trial. See your rights as a clinical trial participant.
- Phased design. Studies escalate deliberately: small doses in few people before larger doses in more people. Each phase has to clear its safety bar before the next one opens.
- Continuous safety monitoring. Adverse events are recorded and graded at every visit. Serious events are reported to the sponsor within tight timeframes, and onward to the ethics committee and the regulator. Many trials also have an independent data safety monitoring board that reviews accumulating data and can halt a study.
- Stopping rules. Protocols specify in advance the events that pause or stop dosing, for you individually or for the whole trial.
None of this makes an experimental treatment predictable. It means somebody is required to notice, act and report when something goes wrong, and there is a paper trail if they don't.
What are the real risks?
It's important to talk about the risks plainly. They vary from trial to trial, but many may include:
- Side effects nobody has seen yet. Investigational treatments have usually undergone extensive laboratory testing before reaching participants, but not every effect can be predicted. Earlier phase trials generally involve more uncertainty because fewer people may have received the treatment before you.
- The treatment may not work. There's no guarantee an investigational treatment will benefit you. The trial is designed to help researchers find that out.
- You may not receive the investigational treatment. Some trials use a placebo, existing treatment or another intervention for comparison.
- Extra procedures. Trials may involve additional blood tests, scans, sometimes biopsies or other procedures, each with its own potential risks.
- Time and travel. Regular appointments and travel can be a significant commitment, so consider the full study schedule before joining.
- Other treatment options. Time on a study treatment is time not spent on another option. This is the conversation to have with your treating specialist, not with a recruitment team.
Who is watching a trial while it's running?
| Who | What they're responsible for |
|---|---|
| Principal investigator | Your medical care and safety at the site; clinical decisions |
| Study coordinator | Day-to-day contact, symptom review, escalation |
| Sponsor / CRO monitors | Checking data accuracy and protocol compliance at the site |
| Human research ethics committee | Ongoing ethical oversight; receives safety reports; can suspend approval |
| Data safety monitoring board | Independent review of accumulating safety data across all sites |
| TGA | Regulatory oversight of the trial and the unapproved product |
Are Phase 1 trials more dangerous than Phase 3?
Not necessarily. The type of risk is different.
Phase 1 studies have more unknowns. There is usually less human data available, particularly in first-in-human studies. They're also run with the tightest controls in clinical research: purpose-built units, staged dose escalation, one participant dosed ahead of the group in first-in-human studies, continuous monitoring, and immediate access to resuscitation facilities.
Phase 3 trials have more information behind them. By this stage, the treatment has usually been studied in many more people and researchers have a better understanding of its side effects. These trials are also larger and often run for longer periods.
If you want the short version: Phase 1 involves more uncertainty and intensive monitoring. Phase 3 involves more established knowledge, but risk is still present.
What happens if something goes wrong?
If you experience a side effect or feel unwell during a trial, tell the site immediately, using the 24-hour contact number you're given at consent. Then:
- You're assessed and treated. Your care comes first, and the study treatment can be paused or stopped for you alone.
- The event is documented as an adverse event, graded, and assessed for whether it's related to the study treatment.
- Serious adverse events are reported to the sponsor and, where required, to the ethics committee and the TGA.
- Suspected unexpected serious reactions can trigger changes to the protocol, the consent form, or the trial's continuation.
Compensation arrangements are described in the consent form. Australian commercial trials typically operate under sponsor indemnity arrangements covering injury caused by the study treatment. Read that section, and ask what it covers and what it excludes. It's one of the two or three sections in a PICF worth reading twice.
How do I check a trial is legitimate?
Do these five checks before your screening visit:
- Find it on a registry. ANZCTR or ClinicalTrials.gov. A registration number should be on the consent form.
- Check the ethics approval. The consent form should name the HREC that approved the study and give an approval reference.
- Identify the site and the investigator. A named doctor at a real clinical facility, contactable independently.
- Read the consent form before your visit. Ask for it in advance. Any site that won't send it early is a site to walk away from.
- Watch for the disqualifiers. You're asked to pay to participate. There's no written consent form. You're pressured to sign on the spot. You're promised a cure or told there's no risk. Contact details are a mobile number and nothing else.
Any one of those five red flags is enough. You don't need a second.
So should you do it?
There isn't one right answer. If you have a health condition and your doctor thinks a clinical trial could be a reasonable option, the supervision of a trial is often more intensive than routine care: more frequent reviews, more testing, faster escalation when something changes. That's a genuine argument in favour, and it's why many participants report feeling closely looked after.
What should make you reconsider? A trial doesn't fit your life, a consent process that feels rushed, or a study team that doesn't make you feel comfortable asking questions.
And once you're enrolled, don't downplay a new symptom because you're worried about being withdrawn from the study. Report it anyway. Even small changes can be important for your safety and help researchers understand the treatment.
Ultimately, participating is your choice. You should feel informed, comfortable asking questions and confident you understand what you're agreeing to.
Sources
- Therapeutic Goods Administration (TGA), Clinical trials (Clinical Trial Notification and Clinical Trial Approval schemes).
- International Council for Harmonisation, ICH E6 Guideline for Good Clinical Practice.
- National Health and Medical Research Council (NHMRC), National Statement on Ethical Conduct in Human Research.
- Australian New Zealand Clinical Trials Registry (ANZCTR).
- World Medical Association, Declaration of Helsinki.
View our currently recruiting clinical trials →
Related reading: Your rights as a clinical trial participant · What to expect, stage by stage · Weighing the benefits against the risks · Can healthy people join a clinical trial?