Clinical trial

A clinical study, English: Clinical Trial, is carried out with test persons or patients to test drugs or medical devices for their efficacy and safety. Clinical trials answer questions from clinical research and improve medical treatment.

There are many different study designs of clinical trials. In principle, a distinction is made between the experimental study in which an intervention is conducted and the non-interventional study (NIS).

In the experimental - interventional study a drug or medical device is tested, which is carried out according to the protocol or study protocol. Experimental studies are always prospective and may include randomisation and blinding. In randomised controlled trials (RCT), there are at least two study arms to which study participants are randomly assigned. In randomised trials, hypotheses are tested, whereby a causality between the intervention and the therapeutic outcome can be established. Randomized studies therefore have a high internal validity, so that the efficacy of the test product can be reliably proven.

In non-interventional studies, also known as observational studies, there are no interventions, but rather documentation of treatments that are carried out without modification by the study. Non-interventional studies can be designed as cohort studies, case-control studies or cross-sectional studies. Non-interventional studies have a high external validity ("real life") and provide information about the actual results of therapies. Non-interventional studies can be prospective or retrospective.

In clinical research, the development of medical devices and medicinal products goes through various phases before approval is granted. For medicinal products, the following stages are classified:

• In phase 0 studies (microdosing), which are not required by law, very low doses of an active substance, which are significantly below the efficacy threshold, are tested on test persons in a low number of cases (approx. 10 - 15 test persons).
• In Phase I studies, active substances are tested for the first time on approx. 20 - 80 healthy volunteers, whereby the transferability from animal experiments to humans is proven. The aim is to prove the safety and tolerability of the drug and to investigate its pharmacokinetics. In the case of therapies for serious diseases, where the substances can cause severe side effects for healthy volunteers, tumour patients can also be recruited, e.g. for the treatment of new chemotherapeutic agents.
• Phase II studies are clinical trials in which the active substance is used on patients for the first time (number of cases: approx. 50 - 200). Here, the positive effects, side effects and the best dose (dose finding) are investigated.
• Phase III studies are clinical studies in which the drug is tested in a larger patient population (150 patients or more). The aim is to prove the efficacy and safety in different patient collectives.
• Phase IV studies are clinical studies after approval. The aim is to evaluate effects and side effects in a larger patient population and to establish a therapeutic threshold.

There are numerous rules and regulations for clinical trials, according to which the trial must be conducted. All studies have to be implemented according to the Declaration of Helsinki, GCP(Good Clinical Practise), the AMG(Medicines Act) and MPG (Medical Devices Act). Furthermore, a positive vote from the responsible ethics committee must be obtained before the start of the clinical trial and approval from the higher federal authorities(BfArM and Paul Ehrlich Institute) should be available. Altogether, all regulations ensure the protection of the test person / patient when participating in studies.