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Stages of PWS Drug Development Overview [VIDEO]

Drug development is a long and costly process that can take up to 15 years and cost up to one billion dollars! In this 7-minute video, Dr. Theresa Strong discusses the stages of PWS Drug Development.

Drug development is a long and costly process that can take up to 15 years and cost up to one billion dollars! In this 7-minute video, Dr. Theresa Strong discusses the stages of PWS Drug Development. Don't have time for the full presentation? We've captured the key points in the notes below.


Steps in the Drug Development Process

It can take up to 15 years and cost up to one billion dollars to bring a drug to market. The steps of drug discovery include:

  • Drug discovery
  • Pre-clinical Testing: to determine if the drug works in animals, has the effect that researchers want and is safe
  • Clinical trials in humans: take place over three phases with increasing numbers of participants
  • Food and Drug Administration (FDA) review
  • FDA approval
  • Post-marketing surveillance: involves a continuing review of safety data after the drug goes to market

Phases of Clinical Trials

One thing to keep in mind is that the three phases of clinical trials are not always completely linear.

Comparison of drug development phases

Phase 1

  • First human study
  • Small trial (10 to 20 people for an orphan drug population)
  • Short in duration
  • Conducted to make sure there no unexpected safety issues
  • Determines how does the drug interacts with the human body

Phase 2

  • Slightly larger population (10 to 50 people for a rare disease)
  • First look at efficacy
  • Looks at different dosing
  • Conducted to look for a biological activity or effect

Phase 3: Pivotal

  • 'Pivotal Trial' 
  • Larger studies (about 100 people for a rare disease)
  • Involves longer exposure to the drug
  • Researchers are looking for evidence that the drug is effective and better than what’s currently available

In all three phases, you have to reach pre-determined endpoints. Before the trial, you have to tell the FDA what your drug is going to do and what effect it is going to have. The drug then must meet those standards in order to gain approval.


After the phase 3 trial....

Gaining Drug Approval

Typically, after a phase 3 study the drug company will file an NDA (New Drug Application) with the FDA. This is a formal proposal to the FDA requesting approval of a new drug for sale/marketing in the U.S. Data from both pre-clinical testing and the human clinical trials will be reviewed and benefits and side effects will be analyzed. The FDA then reviews the information and weighs the benefits and risks and incorporates input of the patient community for consideration during the review process. 


Our #1 challenge in clinical trials: patient participation

Today's Challenge

The #1 reason clinical trials are delayed or not completed is due to insufficient patient participation. You can help us overcome this challenge by reading information about the trials and making an informed decision about whether to participate.  We share up to date information about current PWS clinical trials at where you can find a directory of clinical trials, a map of trial locations and trial specific webinars. 

Not able to participate in a clinical trial? We need your help to establish a strong natural history of PWS! Please enroll in the Global PWS Registry or update your surveys today!


Protections for Study Participants

Many layers of protections are in place for participants of clinical trials.


  • Reviews all information in the Investigational New Drug application and determines if the study can start
  • Reviews all serious adverse events over the course of the study, can place an immediate ’clinical hold’ on the study if safety concerns arise

Study Investigator and team

  • Familiar with drug characteristics
  • Responsible for safety monitoring and reporting
 Institutional Review Board (IRB) at the clinical trial site:
  • Review and approve / monitor biomedical research involving human subjects
  • Protect the rights of the research participants
  • Review and approve informed consent document

Data Safety Monitoring Board

  • Independent group of experts who review safety and efficacy data during trial

For updated information on PWS clinical trial opportunities and to sign up for a monthly PWS Clinical Trial Alert, visit the PWS Clinical Trials page.


PWS Clinical Trials

Topics: Research

Theresa Strong


Theresa V. Strong, Ph.D., received a B.S. from Rutgers University and a Ph.D. in Medical Genetics from the University of Alabama at Birmingham (UAB). After postdoctoral studies with Dr. Francis Collins at the University of Michigan, she joined the UAB faculty, leading a research lab focused on gene therapy for cancer and directing UAB’s Vector Production Facility. Theresa is one of the founding members of FPWR and has directed FPWR’s grant program since its inception. In 2016, she transitioned to a full-time position as Director of Research Programs at FPWR. She remains an Adjunct Professor in the Department of Genetics at UAB. She and her husband Jim have four children, including a son with PWS.