The development of new medicines is a lengthy process with many steps. It usually has two main parts: preclinical trials and clinical trials. It's important to know what makes these two parts different, especially for students studying drugs and health professionals. Here are the main differences between preclinical and clinical trials.

What They Are and Why They Matter

• Preclinical Trials: These tests happen before any human testing begins. The goal here is to collect early information about how well a drug works, how safe it is, and how it acts in the body. Preclinical studies typically use test tubes (in vitro) and animals (in vivo) to find out this information. They help make sure a drug is safe and works well before people try it.

• Clinical Trials: These studies involve real people. The aim is to check how safe and effective new drugs are. The data collected here can help get permission for the drug to be used by everyone. Clinical trials have several phases (Phase I, II, III, and IV), and each phase has its own goals and types of participants.

Different Phases and Participants

• Preclinical Trials:

  • Usually done on a small number of animals.
  • Focuses on understanding dosages, side effects, and how the drug works.
  • Uses animal tests to predict how humans might react.
  • For example, a new drug might be tested on rats and dogs before it’s tested on people.

• Clinical Trials:

  • Involves several phases with more and more participants each time.
  • Phase I: The first phase with 20-100 healthy volunteers to check safety and dosage.
  • Phase II: Expands to hundreds of sick patients to see if the drug works and check for side effects.
  • Phase III: Involves thousands of patients, comparing new treatments to existing ones to see which is better.
  • Phase IV: After the drug is on the market, it is monitored to see how it works in the general population.

Time and Money

• Preclinical Trials:

  • Can take years, usually between 1 to 6 years.
  • Costs about $1.3 billion, which includes animal testing and lab work.

• Clinical Trials:

  • These can take 6 to 7 years or even longer.
  • The total cost can reach about $2.6 billion on average for a new drug from the start of preclinical trials to when it becomes available, with each phase adding to this cost.

Oversight and Regulations

• Preclinical Trials: Follow guidelines from groups like the Food and Drug Administration (FDA) and other review boards. However, they usually don't need a formal approval to begin.

• Clinical Trials: Need strict oversight and must be approved by regulatory agencies before starting. Researchers must submit an Investigational New Drug (IND) application to the FDA to make sure safety and ethics are prioritized.

Success Rates

• Preclinical Trials: Only about 10% of drug candidates that start preclinical testing make it to clinical trials.

• Clinical Trials: Around 70% of drugs that enter Phase I move on to Phase II. However, only about 30% make it to Phase III, and about half of these drugs get approved.

In short, preclinical and clinical trials are two important and different steps in creating new drugs. Each has its own purposes, methods, types of participants, and rules to follow. Knowing these differences helps medical students and professionals understand the complicated world of drug research and development.