What is a Phase 2 Clinical Trial?

A phase 2 clinical trial is conducted to evaluate the effectiveness and safety of a new drug or drug combination for a particular indication.

While a phase 1 trial may recruit healthy volunteers for determining the maximum doses and dose ranges that should be administered, phase 2 is more focused on the therapeutic efficacy in a particular patient population to establish whether or not the drug may ultimately benefit patients and should be studied in a phase 3 trial.

Phase 2 trials are usually randomized, controlled studies evaluating the safety and efficacy of a drug for a particular condition and involve participants selected using narrow criteria, to allow close monitoring of a relatively homogenous patient population.

Although information about safe and well tolerated doses is obtained in earlier phases of drug development, phase 2 trials also assess safety parameters to check for any adverse effects that may have been missed earlier or that may be specific only to a certain patient population.

One of the main goals of phase 2 trials is to determine an appropriate dose and treatment regimen that can be tested in phase 3 trials. Dose response studies may therefore be carried out and confirmed in the phase 2 trial. The doses used in phase 2 are generally less than the highest of those used in phase 1 and the treatment is given to a larger population of people in phase 2, usually 100 to 300 patients.

Phase 2 trials are sometimes further divided into:

  • Phase 2a
  • Phase 2b

Phase 2a is focused specifically on dosing requirements. A small number of patients are administered the drug in different quantities to evaluate whether there is as a dose-response relationship, which is an increase in response that correlates with increasing increments of dose. In addition, the optimal frequency of dose is also explored.

Phase 2b trials are designed specifically to rigorously test the efficacy of the drug in terms of how successful it is in treating, preventing or diagnosing a disease.

Further Reading

Last Updated: Feb 26, 2019

Dr. Ananya Mandal

Written by

Dr. Ananya Mandal

Dr. Ananya Mandal is a doctor by profession, lecturer by vocation and a medical writer by passion. She specialized in Clinical Pharmacology after her bachelor's (MBBS). For her, health communication is not just writing complicated reviews for professionals but making medical knowledge understandable and available to the general public as well.

Citations

Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Mandal, Ananya. (2019, February 26). What is a Phase 2 Clinical Trial?. News-Medical. Retrieved on September 21, 2019 from https://www.news-medical.net/health/What-is-a-Phase-2-Clinical-Trial.aspx.

  • MLA

    Mandal, Ananya. "What is a Phase 2 Clinical Trial?". News-Medical. 21 September 2019. <https://www.news-medical.net/health/What-is-a-Phase-2-Clinical-Trial.aspx>.

  • Chicago

    Mandal, Ananya. "What is a Phase 2 Clinical Trial?". News-Medical. https://www.news-medical.net/health/What-is-a-Phase-2-Clinical-Trial.aspx. (accessed September 21, 2019).

  • Harvard

    Mandal, Ananya. 2019. What is a Phase 2 Clinical Trial?. News-Medical, viewed 21 September 2019, https://www.news-medical.net/health/What-is-a-Phase-2-Clinical-Trial.aspx.

Comments

The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News-Medical.Net.
Post a new comment
Post
You might also like... ×
Chlamydia vaccine shows promise after a successful clinical trial