The Austrian Medicines Act (AMG) distinguishes between two categories: Non-interventional studies (NIS, formerly observational studies) and interventional clinical trials. In order to carry out a NIS, the medicinal product must be approved and used strictly in accordance with the requirements of this approval. Furthermore, there must be no examinations outside the routine or other burdens for the patients. In contrast, interventional clinical trials can also be used to investigate unauthorised medicinal products and additional investigations are permitted. Both forms serve to answer scientific questions.

Interventional studies are divided into phases, phase I represents the earliest phase and also includes studies with first application in humans. While Phase I primarily focuses on possible adverse effects of the drug, Phase II already investigates possible therapeutic effects. Phase III studies are also referred to as pivotal studies, as the outcome of these studies is decisive for later approvals. Phase IV studies describe the investigation of medicinal products already authorised if the authorised therapeutic use is extended by additional investigations.

Interventional clinical trials must be approved by both the regulatory authority (BASG) and the ethics committees.

The submission documents consist of the following three parts:

1. information on the manufacture, stability and purity of the investigational medicinal product
2. Information on pharmacology and toxicology (primarily data from animal studies)
3. Results of previous clinical trials, study protocol and patient education.

These conditions for the authorisation of intervention studies are uniformly regulated in Europe. There are (normally) no clinical trials of new medicinal products without prior animal studies. In most cases, years of preclinical experience with the drug are already available before phase I studies are even started.

Authorities and ethics committees play an important supervisory role in ensuring comparable standards in drug studies and the highest possible patient safety.

Patients participating in a study must explicitly agree to participate. This consent follows a careful oral explanation by the investigator and a thorough review of the patient information and the signing of the informed consent form.

Detailed contact information is an essential part of patient information. In the event of ambiguities, the patient must be given the opportunity to contact a contact person (e.g. the investigator or patient advocate).

The patient can withdraw from a clinical trial at any time without giving reasons and with continuous best medical care.