Clinical Research Basics
Clinical trials are part of the new drug development process. Before a new drug reaches the market and is available for human use, it must go through a rigorous, complicated and lengthy process of testing.
While it is true that new drug development process is very complicated, some phases of the development are more labour intensive and costly. The cost of research and development can be USD 2.6 billion compared to USD 179 million in 1970s (2).
While one may expect that the number of new drugs (new molecular entities) should be high given that pharmaceutical and biopharmaceutical companies invest billions in R&D, the reality is different as shown in the chart below(3). In 2017 there were 47 novel drug approvals by the FDA (4).
I will skip the pre-clinical research and jump immediately to clinical research.
Clinical research includes testing of drugs on humans in well designed and controlled clinical trials and is divided into 4 Phases.
Phase I (first in humans)
Phase I clinical trials include fewer than 100 healthy volunteers. The goal is to find how drug interacts with the human body and how it is metabolised (pharmacokinetics/pharmacodynamics). Different doses of drug are tested to find the best and safest dose before moving to the next phase. All side effects are actively monitored and recorded. Around 70% of drugs move to the Phase II.
Phase II
Phase II clinical trials include few hundreds patients with a disease for which the drug is being developed. Typically 100–300 patients are involved. The focus is on the efficacy of the drug (whether the drug works) and to assess its safety. Approximately 33% of drugs move to Phase III.
Phase III (pivotal studies)
These clinical trials are very complicated, expensive, and time-consuming, can last several years and include from 300–3000 patients. Phase III clinical trials are definitive assessment of the efficacy and safety of the drug. New drug is compared to the existing treatment to determine the benefits. Phase 3 studies provide most of the safety data. After successful conduct of Phase III trials, large packages of data containing all results of all clinical trials and additional information related to the manufacturing of the drug, pre-clinical results and administrative information, are being submitted to the regulatory agencies like FDA and EMA for the assessment.
Approximately 25–30% of drugs move to the next phase.
Phase IV (post marketing surveillance)
After the drug has reached the market, additional trials that monitor the safety of the drug are being conducted.
Literature & Sources:
2. https://www.ifpma.org/wp-content/uploads/2017/02/IFPMA-Facts-And-Figures-2017.pdf
3.http://phrma-docs.phrma.org/sites/default/files/pdf/biopharmaceutical-industry-profile.pdf
4.https://www.fda.gov/Drugs/DevelopmentApprovalProcess/DrugInnovation/ucm537040.htm
