Placebo Not Needed: Controls in Clinical Trials
- Jackie Lochridge
- 43 minutes ago
- 2 min read
What is a control?
If you've ever read a news article or seen an advertisement about a new medication, you may have heard of placebo-controlled trials. A placebo-controlled trial is used to prove that a new medication or treatment is better at treating a target condition than nothing. The placebo is similar to the drug (e.g. a tablet or infusion) so that trial participants and doctors don't know if patients are receiving the drug or "sugar pill."
In general, a control is a group that is not exposed to the experimental treatment. Having a control ensures that changes are due to the new treatment and not other factors. While placebo-controlled trials are very common and provide evidence that a new drug is effective compared to no treatment, there are other options.
Non-placebo controls
Some specialties such as oncology commonly compare new drugs to existing treatments. These trials have three main categories with slightly different objectives. Non-inferiority trials seek to determine if a new treatment is at least as good as existing treatment. Equivalence trials examine if a new treatment is about the same as existing options. Superiority trials investigate if a new treatment is better than existing treatment.
Why not placebo?
Some medical professionals argue that it is unethical to use a placebo for control groups if other treatment options exist. While this can't be done for drugs that are the first and only treatment option for the condition, many conditions have current treatments to use for control groups. Using existing treatments as controls allows patients in both groups greater opportunity to experience improvement in their condition.
Practical considerations also drive decision-making in trial design. If the number of patients who qualify for the trial is small, an equivalence or non-inferiority design is more achievable. If the sample size is very large, a superiority trial may be pursued. All of these trial designs make use of randomly selected groups and have a control: both of which are essential to ensure rigorous testing.
References
Trial Designs—Non-inferiority vs. Superiority vs. Equivalence. www.certara.com. https://www.certara.com/knowledge-base/trial-designs-non-inferiority-vs-superiority-vs-equivalence/
Streiner DL. Alternatives to placebo-controlled Trials. The Canadian Journal of Neurological Sciences Le Journal Canadien Des Sciences Neurologiques. 2007;34 Suppl 1:S37-41. doi:https://doi.org/10.1017/s0317167100005540
American Medical Association. Ethical Use of Placebo Controls in Research | ama-coe. AMA Code of Medical Ethics. https://code-medical-ethics.ama-assn.org/ethics-opinions/ethical-use-placebo-controls-research
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