The Basics of Drug Development: A comprehensive overview

Drug development is a complex and highly regulated process that transforms a scientific discovery into a viable therapeutic product. This journey, which typically spans over a decade, requires significant financial investment and multidisciplinary expertise. Understanding the fundamentals of drug development is essential for professionals and students in pharmaceutical sciences, chemistry, and engineering.

Developing a new drug is a lengthy and intricate process that involves multiple stages, each with its own set of challenges. The average timeline for drug development is 10-15 years, with costs exceeding billions of dollars.

One of the major hurdles in drug development is the high attrition rate. According to data from the Pharmaceutical Research and Manufacturers of America (PhRMA), only about 12% of drug candidates that enter clinical trials ultimately receive regulatory approval. The reasons for failure vary and include lack of efficacy, safety concerns, and manufacturing challenges.

For those interested in the latest trends and advancements in drug development, the IQVIA Institute for Human Data Science provides valuable insights through its annual trend report. The Global Trends in R&D 2024 report explores the current state of pharmaceutical research and development, highlighting key drivers of innovation, challenges in the industry, and the evolving regulatory landscape.

IQVIA - The Global Trends in R&D 2024 report

Furthermore, regulatory requirements add another layer of complexity. Regulatory agencies such as the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA) enforce stringent guidelines to ensure that only safe and effective drugs reach the market. Companies must submit comprehensive data packages that demonstrate the quality, safety, and efficacy of the drug candidate, requiring years of rigorous testing and documentation.

Drug development is inherently multidisciplinary, requiring collaboration among scientists, engineers, clinicians, and regulatory professionals. Each discipline plays a crucial role in different phases of the process.

Chemists and biologists contribute to the early discovery phase by identifying potential drug targets and designing molecules with therapeutic potential. Medicinal chemists work on optimizing these molecules for improved activity and reduced toxicity. Engineers, particularly chemical and biomedical engineers, are involved in designing scalable manufacturing processes and developing drug delivery systems that enhance bioavailability and patient compliance.

Clinicians and medical researchers are responsible for designing and conducting clinical trials to evaluate the safety and efficacy of new drug candidates. Meanwhile, regulatory experts ensure that the development process adheres to international standards and guidelines, facilitating interactions with health authorities to expedite approvals while maintaining patient safety.

A prime example of this multidisciplinary collaboration is the rapid development of COVID-19 vaccines. The integration of advanced mRNA technology, cutting-edge bioprocess engineering, and global regulatory cooperation enabled the unprecedented acceleration of vaccine approval and distribution within a year—demonstrating the power of cross-disciplinary expertise in drug development.

The drug development process consists of several distinct stages, each critical to ensuring the final product’s safety and effectiveness. Currently, the first step in drug development is identifying a biological target, such as a protein or receptor, that plays a key role in disease pathology. Scientists then screen thousands of compounds to find a “lead” molecule that interacts effectively with the target. This process, known as high-throughput screening (HTS), utilizes automated robotic systems and large chemical libraries to identify promising candidates.

Although drug development today follows a rigorous, highly structured process, this was not always the case. A notable example is the discovery and development of insulin, a breakthrough in diabetes treatment. The history of insulin’s discovery and early use is well described in the compelling video by Patrick Kelly on his YouTube channel:

Once a lead compound is identified, it undergoes preclinical testing in laboratory and animal models to assess its pharmacokinetics (how the drug is absorbed, distributed, metabolized, and excreted) and toxicology. These studies help determine safe dosage ranges and potential adverse effects before proceeding to human trials. Only about 10% of compounds that enter preclinical testing progress to clinical trials.

Clinical trials are conducted in three phases:

• Phase I: Small-scale trials (20-100 participants) focusing on safety and dosage.

• Phase II: Medium-scale trials (100-500 participants) assessing efficacy and side effects.

• Phase III: Large-scale trials (1,000-5,000 participants) evaluating overall therapeutic benefits and risks compared to existing treatments.

Each phase must demonstrate success before advancing to the next stage, making clinical trials the most time-consuming and expensive part of drug development.

After successful clinical trials, a New Drug Application (NDA) or Biologics License Application (BLA) is submitted to regulatory agencies. These applications include extensive data on the drug’s safety, efficacy, and manufacturing processes. If approved, the drug can be marketed and prescribed to patients. However, post-marketing surveillance (Phase IV) continues to monitor long-term safety and effectiveness.

Image adapted from: Jonker, A.H., Tataru, EA., Graessner, H. et al. The state-of-the-art of N-of-1 therapies and the IRDiRC N-of-1 development roadmap. Nat Rev Drug Discov 24, 40–56 (2025). https://doi.org/10.1038/s41573-024-01059-3

Drug development is a rigorous, multidisciplinary process that requires expertise in various scientific and regulatory fields. Despite its challenges, this process is crucial for delivering innovative therapies to patients worldwide. As advancements in artificial intelligence, gene therapy, and personalized medicine continue to shape the future of drug development, professionals and students must stay informed about emerging trends and best practices. By fostering interdisciplinary collaboration and leveraging cutting-edge technologies, the pharmaceutical industry can enhance drug discovery and improve patient outcomes.