3.1. Explain the process of drug development

This guide will help you answer 3.1. Explain the process of drug development.

The process of drug development refers to the series of steps required to bring a new drug or treatment from discovery to approval and availability for public use. It is a structured, scientific process designed to ensure that a drug is both safe and effective for treating health conditions. Drug development involves rigorous research, testing, and compliance with legal regulations.

The process of drug development can take several years and typically costs large sums of money. It is designed to protect public safety by ensuring treatments undergo substantial scrutiny before they reach healthcare providers and patients.

Main Stages

The process of drug development can generally be divided into five main stages:

• Discovery and preclinical research
• Clinical trials (Phases 1–3)
• Regulatory approval
• Post-marketing surveillance (Phase 4)

Each stage has a specific purpose and contributes to determining whether a drug is safe, effective, and suitable for public use.

Discovery and Preclinical Research

The process begins with discovery. During this phase, scientists identify a target for the drug and develop a compound that may work to treat a specific condition. A “target” might be a protein in the body that plays a role in a disease. Scientists aim to find a way to influence this target, often working with computer programs, laboratory testing, and new technologies.

Steps in the Discovery Phase:

1. Identifying the problem: Scientists study diseases or conditions that require new treatment options. They analyse how these diseases function within the human body.
2. Target identification: Researchers determine biological targets (molecules or proteins) that the drug could act upon.
3. Drug candidate selection: Multiple chemical or biological compounds are tested to find the one most likely to succeed. This might involve thousands of compounds.

Once potential compounds are identified, they are tested in the preclinical research phase.

Preclinical Research

Preclinical research involves laboratory testing to assess whether the selected compound works effectively and whether it is safe enough for further development. Testing is carried out on cells, tissues, and sometimes animals. This step ensures that low-risk substances proceed to human trials, improving safety when trials begin.

Key information gathered during preclinical testing includes:

• Whether the drug reaches the intended target.
• How long it stays effective in the system.
• How it is absorbed, distributed, metabolised, and excreted (a process called pharmacokinetics).
• Potential toxicity (harmful side effects).

In the UK, strict regulations under the Medicines and Healthcare products Regulatory Agency (MHRA) ensure ethical standards are followed during preclinical trials. Following ethical research guidelines is especially important when testing on animals.

If a drug passes preclinical testing, the next step is to test the drug on humans through clinical trials.

Clinical Trials (Phase 1–3)

Clinical trials involve testing on human participants to determine how well the drug works and if it is safe. These trials are carried out in phases, each building on the evidence gained from the previous phase.

Phase 1: Testing Safety

The first phase focuses on safety. This involves a small group of healthy volunteers (usually 20–100 people).

The purpose of Phase 1 includes:

• Assessing how safe the drug is at different doses.
• Studying how the drug interacts with the human body.
• Monitoring side effects.

The aim is not yet to test effectiveness, but to make sure participants are not at high risk from serious side effects.

Phase 2: Testing Effectiveness and Dosage

After passing Phase 1, the drug is tested on a group of people with the targeted disease or condition (approximately 100–300 participants). In this phase, researchers:

• Assess whether the drug actually works in treating the condition.
• Determine the most effective dosage range.
• Monitor for any ongoing safety concerns.

Both safety and effectiveness are reviewed at this stage, but further large-scale testing is still required.

Phase 3: Confirming Effectiveness and Monitoring Long-Term Safety

Phase 3 trials allow for testing on a much larger group of patients (usually at least 1,000 participants). This involves multiple hospitals and clinics, often across different countries.

The purpose of this stage is to:

• Confirm the drug’s effectiveness for specific conditions.
• Compare the drug’s performance against existing treatments or placebos (inactive substances).
• Assess longer-term risks and side effects.

Phase 3 is the final stage before applying for regulatory approval. Data from this stage is usually submitted to official authorities like the MHRA or the European Medicines Agency (EMA).

Regulatory Approval

After completing the clinical trial phases, the pharmaceutical company submits an application to regulatory bodies like the MHRA. This submission is known as a “New Drug Application” (NDA) or “Marketing Authorisation Application” (MAA). The application includes all research data collected during preclinical and clinical trials.

Regulatory agencies examine the evidence to check whether:

• The drug works as intended.
• Safety data confirms that the benefits outweigh the risks.
• The manufacturing process is reliable and consistent.

In the UK, healthcare regulators ensure new treatments meet required standards under legal frameworks like the Medicines Act 1968.

Approval can take months or years to process. Once approved, the drug can be marketed, prescribed, and sold.

Post-Marketing Surveillance (Phase 4)

Phase 4 takes place after a drug is approved. This is often referred to as “post-marketing surveillance” because the drug is now in real-world use.

This phase involves monitoring the long-term performance and safety of the drug. This step remains important because issues may arise once the drug is used widely across diverse patient populations.

Common goals of post-marketing surveillance include:

• Identifying rare side effects not detected during Phase 3.
• Assessing long-term risks and benefits.
• Evaluating how the drug interacts with other commonly prescribed medications.

Regulators and researchers rely heavily on feedback from healthcare professionals and patients during this phase.

Ethics and Regulations in Drug Development

Throughout every stage, ethical considerations play a critical role. Protecting patients and volunteers is at the centre of drug development. Strict regulations aim to ensure that all participants give informed consent and understand the possible risks of involvement.

In the UK, the Good Clinical Practice (GCP) guidelines oversee how every trial is conducted. These guidelines ensure patient safety, ethical standards, and trustworthy data collection.

Timeframes and Costs

The drug development process can span 10–15 years. A significant proportion of the time is spent in preclinical and Phase 3 clinical trials. Costs include laboratory testing, manufacturing, compliance with legal standards, and trial expenses. Many potential drugs fail during this process, meaning research investments can lead to significant losses if the final drug isn’t viable.

Challenges in Drug Development

Certain challenges are common throughout the drug development process, such as:

• High failure rates: Most compounds tested never make it to human trials.
• Ethical concerns: Balancing the risks for volunteers with the need for effective treatments.
• Access: Once approved, some drugs may cost too much for some populations to access them.

Despite these challenges, drug development remains vital for advances in healthcare. It allows scientists to address unmet medical needs and create treatments for diseases that previously had limited options.

Conclusion

Drug development is a lengthy, scientific process designed to ensure medications are effective and safe. Through discovery, testing, and regulatory stages, each potential treatment must meet high standards before it can be approved. While time-consuming and costly, this process is vital for improving healthcare outcomes and saving lives across the UK and beyond.