Decoding Drug Development Phases

In some practices, particularly those affiliated with academic institutions, nurse practitioners have the opportunity to offer participation in clinical trials as a treatment recourse to patients. These NPs serve as an intermediary between researchers and patients monitoring treatment progress, side effects and outcomes. In other instances, as a nurse practitioner you may recommend participation in a clinical trial to a patient who has few other options. Whatever the extent of your interaction with the pharmaceutical industry and research, background knowledge about how drugs are developed is in order.

As a nurse practitioner, the various phases of clinical trials are the terminology related to drug development you are most likely to encounter in your practice. To understand potential risks to your patients, you must understand the basics of these phases.

Pre-Clinical Trials

Medical treatments begin development in the lab, far from real, ‘live’ patients. Promising treatment options are then tested on animals before reaching humans in the hospital and clinic setting. Once a company believes it has developed a treatment worth of testing on individuals, it must obtain permission from the FDA undergoing an extensive approval process. Prior research is reviewed and the plan for initiating testing on humans scrutinized. If the FDA approves the drug or treatment for clinical testing, researchers begin conducting phased clinical trials.

Phase 1 Clinical Trials

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Who? Phase one clinical trials are the frontline of clinical research. A small group of patients, anywhere from 20 to 100, are selected to participate in the first phase of a clinical trial. This initial group is then subdivided into smaller groups called cohorts. The first cohort receives an initial dose of the drug. If the first cohort does not experience significant negative side effects, higher doses may be tested and the second cohort begins treatment.

When? Phase 1 clinical trials last several months.

Why? Establishing drug safety and dosage are the primary concern of phase 1 clinical trials. If a drug isn’t safe, there’s no reason to put greater numbers of study participants at potential risk for detrimental side effects.

What’s the outcome? About 70% of drugs entering phase 1 clinical trials move on to phase 2.

Phase 2 Clinical Trials

Who? Up to several hundred participants with the medical condition being treated participate in phase 2 clinical trials to help further establish the drug’s safety profile.

When? Typically, phase 2 clinical trials last several months to two years.

Why? Drug efficacy and side effects are the focus of phase 2 clinical trials. While safety is initially studied in phase 1, new side effects may appear with long-term use. A larger group of participants allows researchers to gather more robust information.

What’s the outcome? About 33% of drugs entering phase 2 clinical trials move on to phase 3.

Phase 3 Clinical Trials

Who? Anywhere from 300 to 3,000 individuals with the disease or condition enroll in phase 3 clinical trials.

When? Phase 3 clinical trials are lengthy lasting anywhere from one to three years.

Why? Evaluating drug efficacy is the main focus of phase 3 trials. Patients participating in the study are placed in either a control group getting the standard treatment for their disease or condition or the  study group that receives the new drug. In some cases the nurse practitioner may know which group the patient belongs to (single-blind study). In other cases, both the patient and provider may be unaware of the group within which the patient falls (double-blind). This process ultimately determines if the new drug is more effective than other existing treatment options. 

What’s the outcome? 25-30% of drugs entering phase 3 clinical trials move on to receive FDA approval.

What’s Next?

Once a phase 3 clinical trial is complete, the FDA reviews the results of these trials. If the treatment proves safe and effective, the drug may be approved becoming available to all patients. Although the drug has been approved, research continues in ‘phase 4’ focused on safety and efficacy of long-term treatment.


You Might Also Like: Guide to Finding Clinical Trials for Your Patients


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