What does it mean to combine phases of clinical trials during vaccine development?
What does it mean to combine phases of clinical trials during vaccine development?
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There are several reasons why scientists might combine clinical trial phases in the process of developing a vaccine. Usually, testing a vaccine occurs in three to four phases after early, preclinical research is done in the lab or on animals, like primates. Phase 1 trials are where researchers try to study very basic elements of vaccines in small groups of people to see how the body absorbs the drug, how long it stays in the body, and to show how toxic the vaccine may be depending on the dosage. Phase 2 trials examine how effective a vaccine is in different doses and looks at short-term side effects, usually with several hundred patients. Finally, phase three trials involve hundreds or thousands of volunteers. They are used to see how well a vaccine may work and what types of side effects are most common over a longer period of time. Phase three trials often determine whether the benefits of a vaccine outweigh the risks. Many vaccines never reach the the third phase as the vaccines might not be shown to be beneficial, may have dangerous side effects, or might not work as well in humans as they do in animal studies. Developing vaccines often takes many years, sometimes decades, and this can cause major challenges when a disease like COVID-19 is spreading quickly around the world. Vaccines do not usually keep up with the speed of a pandemic, so researchers often combine phases 1 and 2 or 2 and 3 to speed up the development and testing processes. This helps scientists learn much more quickly whether a vaccine will continue being studied if it appears safe and effective or if it will be stopped because it has not shown to help prevent severe symptoms of an illness. When study phases are combined, the same safety protocols and standards are used as in traditional trials and all safety requirements must be met even at a more rapid testing speed.
There are several reasons why scientists might combine clinical trial phases in the process of developing a vaccine. Usually, testing a vaccine occurs in three to four phases after early, preclinical research is done in the lab or on animals, like primates. Phase 1 trials are where researchers try to study very basic elements of vaccines in small groups of people to see how the body absorbs the drug, how long it stays in the body, and to show how toxic the vaccine may be depending on the dosage. Phase 2 trials examine how effective a vaccine is in different doses and looks at short-term side effects, usually with several hundred patients. Finally, phase three trials involve hundreds or thousands of volunteers. They are used to see how well a vaccine may work and what types of side effects are most common over a longer period of time. Phase three trials often determine whether the benefits of a vaccine outweigh the risks. Many vaccines never reach the the third phase as the vaccines might not be shown to be beneficial, may have dangerous side effects, or might not work as well in humans as they do in animal studies. Developing vaccines often takes many years, sometimes decades, and this can cause major challenges when a disease like COVID-19 is spreading quickly around the world. Vaccines do not usually keep up with the speed of a pandemic, so researchers often combine phases 1 and 2 or 2 and 3 to speed up the development and testing processes. This helps scientists learn much more quickly whether a vaccine will continue being studied if it appears safe and effective or if it will be stopped because it has not shown to help prevent severe symptoms of an illness. When study phases are combined, the same safety protocols and standards are used as in traditional trials and all safety requirements must be met even at a more rapid testing speed.
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What our experts say
There are several reasons why scientists might combine clinical trial phases in the process of developing a vaccine. Usually, testing a vaccine occurs in three to four phases after early, preclinical research is done in the lab or on animals, like primates.
Phase 1 trials are where researchers try to study very basic elements of vaccines in small groups of people to see how the body absorbs the drug, how long it stays in the body, and to show how toxic the vaccine may be depending on the dosage. Phase 2 trials examine how effective a vaccine is in different doses and looks at short-term side effects, usually with several hundred patients. Finally, phase three trials involve hundreds or thousands of volunteers. They are used to see how well a vaccine may work and what types of side effects are most common over a longer period of time.
Phase three trials often determine whether the benefits of a vaccine outweigh the risks. Many vaccines never reach the the third phase as the vaccines might not be shown to be beneficial, may have dangerous side effects, or might not work as well in humans as they do in animal studies.
Developing vaccines often takes many years, sometimes decades, and this can cause major challenges when a disease like COVID-19 is spreading quickly around the world. Vaccines do not usually keep up with the speed of a pandemic, so researchers often combine phases 1 and 2 or 2 and 3 to speed up the development and testing processes. This helps scientists learn much more quickly whether a vaccine will continue being studied if it appears safe and effective or if it will be stopped because it has not shown to help prevent severe symptoms of an illness.
When study phases are combined, the same safety protocols and standards are used as in traditional trials and all safety requirements must be met even at a more rapid testing speed.
There are several reasons why scientists might combine clinical trial phases in the process of developing a vaccine. Usually, testing a vaccine occurs in three to four phases after early, preclinical research is done in the lab or on animals, like primates.
Phase 1 trials are where researchers try to study very basic elements of vaccines in small groups of people to see how the body absorbs the drug, how long it stays in the body, and to show how toxic the vaccine may be depending on the dosage. Phase 2 trials examine how effective a vaccine is in different doses and looks at short-term side effects, usually with several hundred patients. Finally, phase three trials involve hundreds or thousands of volunteers. They are used to see how well a vaccine may work and what types of side effects are most common over a longer period of time.
Phase three trials often determine whether the benefits of a vaccine outweigh the risks. Many vaccines never reach the the third phase as the vaccines might not be shown to be beneficial, may have dangerous side effects, or might not work as well in humans as they do in animal studies.
Developing vaccines often takes many years, sometimes decades, and this can cause major challenges when a disease like COVID-19 is spreading quickly around the world. Vaccines do not usually keep up with the speed of a pandemic, so researchers often combine phases 1 and 2 or 2 and 3 to speed up the development and testing processes. This helps scientists learn much more quickly whether a vaccine will continue being studied if it appears safe and effective or if it will be stopped because it has not shown to help prevent severe symptoms of an illness.
When study phases are combined, the same safety protocols and standards are used as in traditional trials and all safety requirements must be met even at a more rapid testing speed.
Context and background
Due to the huge need to create vaccines and treatments for COVID-19, scientists, pharmaceutical, and biotechnology companies have worked to speed up the development process as quickly and safely as possible. A common option many companies have chosen to use is combining separate clinical trial phases into one. While all of the traditional safety requirements and standards must still be followed, this process has allowed vaccine development to occur at a pace that has never occurred before. Due to this work, several vaccines have already been submitted to national regulatory agencies for approval and a few are already being given to high-risk populations.
Due to the huge need to create vaccines and treatments for COVID-19, scientists, pharmaceutical, and biotechnology companies have worked to speed up the development process as quickly and safely as possible. A common option many companies have chosen to use is combining separate clinical trial phases into one. While all of the traditional safety requirements and standards must still be followed, this process has allowed vaccine development to occur at a pace that has never occurred before. Due to this work, several vaccines have already been submitted to national regulatory agencies for approval and a few are already being given to high-risk populations.
Resources
- How to expedite early‐phase SARS‐CoV‐2 vaccine trials in pandemic setting—A practical perspective (BPS)
- 22 case studies where phase 2 and phase 3 trials had divergent results (U.S. FDA)
- When is it appropriate to combine phases (EMA Europa)
- Phase I/II clinical trial (U.S. NCI)
- Pandemic vaccine trials: expedite, but don’t rush (SAGE)
- Accelerating a safe and effective COVID-19 vaccine (WHO)
- How to expedite early‐phase SARS‐CoV‐2 vaccine trials in pandemic setting—A practical perspective (BPS)
- 22 case studies where phase 2 and phase 3 trials had divergent results (U.S. FDA)
- When is it appropriate to combine phases (EMA Europa)
- Phase I/II clinical trial (U.S. NCI)
- Pandemic vaccine trials: expedite, but don’t rush (SAGE)
- Accelerating a safe and effective COVID-19 vaccine (WHO)
