The Role, Objectives and Characteristics of Phase II CRO Clinical Trials

During the Phase I stage of a clinical trial, clinical trial companies investigate the effects of a drug on around 20 to 80 patients over a period of several months. These are patients who do not have any health conditions.

This phase monitors the effects of a drug and evaluates its safety as well as the safe dosage of the medication which can be taken and the best way in which the drug can be administered.

If the drug is deemed to be safe, it moves to Phase II of the clinical trial.

Goal of Phase II Trials

The goal of Phase II clinical trials is to estimate the activity of a new drug or treatment and assesses its toxicity and therapeutic efficacy. The outcome of these pilot studies determine whether the new drug is promising and a further large scale Phase III testing is warranted. The outcome is based on the observed response whether using the trial drug results in an improvement over existing drugs or treatments.

The number of patients in Phase II CRO trials varies between 20 and 50 and the trial is able to detect improvements of over 10%. Improvements of less than 5% can only be detected in much larger sample sizes.

In cancer therapeutics Phase II studies play a prominent role as new treatments arise from a combination of existing therapies or result from by varying the radiation dosage.

Objectives of Phase II Trials

Phase II trials have three main objectives

  1.       Test whether the new drug or treatment will benefit the patient
  2.       To screen the new drug for the response activity
  3.       To extend knowledge about the toxicology and pharmacology of the treatment.

One of the important characteristics of Phase II trials is the use of rules for early stopping.

If upon testing sufficient evidence is obtained that the treatment has a positive effect, the treatment is considered to be promising and effective, resulting in the testing being terminated.

On the contrary, if the treatment does not result in an appreciable improvement in the patient‘s condition, the test is terminated and the treatment does not go on to Phase III.                             

How Phase II Trials Differ From Phase I Trials

While Phase I trials recruits healthy patient volunteers to determine maximum doses and what dose ranges should be administered, Phase II clinical trials are focused on therapeutic efficacy among a particular sample of patients in order to establish if the drug being trialed will benefit patients and if the drug merits consideration to be studied in a Phase III trial.

Phase II trials are generally randomized and controlled evaluating the efficacy and safety of a drug for a specific condition. The research involves the selection of participants using narrow criteria, allowing clinical trial companies to closely monitor the patient sample.

Although the earlier phases provide information about well-tolerated and safe doses of drug development, Phase II trials assess safety parameters for checking any adverse effects which could have been missed or may relate specifically to only