Beyond Achondroplasia

Growing together with Clara

Understanding clinical trials


This is a quite delicate subject once I´ve realized that many people, specially parents, see clinical trials as a way to convert their children or themselves into guinea pigs. Well, the goal of a clinical trial is to improve health and knowledge and is designed in the way to work with and for safety, in all phases of the trial.

In this review published on 2013: “Small clinical trials are necessary when there are difficulties in recruiting enough patients for conventional frequent statistical analyses to provide an appropriate answer. These trials are often necessary for the study of rare diseases as well as specific study populations e.g. children. It has been estimated that there are between 6,000 and 8,000 rare diseases that cover a broad range of diseases and patients.

In the European Union these diseases affect up to 30 million people, with about 50% of those affected being children. Therapies for treating these rare diseases need their efficacy and safety evaluated but due to the small number of potential trial participants, a standard randomised controlled trial is often not feasible. There are a number of alternative trial designs to the usual parallel group design, each of which offers specific advantages, but they also have specific limitations. Thus the choice of the most appropriate design is not simple”

“In children the issue is not restricted solely to rare diseases as the difficulty in recruiting sufficient numbers of patients is a problem for even frequent diseases. This difficulty is mainly due to ethical and psychological considerations, which not only represent an obstacle to running clinical trials but also to protecting the children”

Clinical trials provide the basis for the development and marketing of new drugs, biological products, and medical devices. Sometimes, the safety and the effectiveness of the experimental approach or use may not be fully known at the time of the trial.
Some trials may provide participants with the prospect of receiving direct medical benefits, like the trial for BMN-111: A Phase 2 Study of BMN 111 to Evaluate Safety, Tolerability, and Efficacy in Children With Achondroplasia (ACH)

Most trials involve some risk of harm or injury to the participant, although it may not be more than the risks related to routine medical care or disease progression. But for approved trials the risks of participation have been minimized and are reasonable in relation to anticipated benefits. Many trials require participants to undergo additional procedures, tests, and assessments based on the study protocol. These will be described in the informed consent document for a particular trial.


Image taken from Lets skip ahead

Clinical trials in rare diseases present several challenges:

1. The trials can have more variability and may have power to detect only large treatment effects 

2. The importance of study planning is magnified and planning requires more time

3. Limited availability of resources: willing trial participants and funding sources

4. One substantial issue in a small clinical trial is that it can be harder to minimize biasa tendency of an estimate to deviate in one direction from a true value. The smaller the sample of the population under a test might translate into an increased risk to take incorrect conclusions for the full population.

With this very simple presentation of what is a clinical trial, I want to clarify the use and utility of a clinical trial and that a vast number of experts work together in the way to develop new drugs to improve lives and not to make them worst.

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