With the information from the current American Society of Hematology (ASH) 2013 beginning to flood out, we'll be reading of findings in different trial phases.
Your decision on whether to join a treatment trial may well be influenced by the phase of the trial, so it is well worth understanding what is covered in each phase.
From the Wikipedia references:
Phases of clinical research
"Clinical trials involving new drugs are commonly classified into four phases. Each phase of the drug approval process is treated as a separate clinical trial. The drug-development process will normally proceed through all four phases over many years. If the drug successfully passes through Phases 0, 1, 2, and 3, it will usually be approved by the national regulatory authority for use in the general population.
Phase 0: Pharmacodynamics and Pharmacokinetics
Phase 1: Screening for safety
Phase 2: Establishing the efficacy of the drug, usually against a placebo
Phase 3: Final confirmation of safety and efficacy
Phase 4: Sentry studies during sales
Each phase has a different purpose and helps scientists answer a different question:
Phase 0 trials are the first-in-human trials. Single subtherapeutic doses of the study drug are given to a small number of subjects (10 to 15) to gather preliminary data on the agent's pharmacodynamics (what the drug does to the body) and pharmacokinetics (what the body does to the drugs).
In Phase 1 trials, researchers test an experimental drug or treatment in a small group of people (20–80) for the first time to evaluate its safety, determine a safe dosage range, and identify side effects.
In Phase 2 trials, the experimental treatment is given to a larger group of people (100–300) to see if it is effective and to further evaluate its safety.
In Phase 3 trials, the treatment is given to large groups of people (1,000–3,000) to confirm its effectiveness, monitor side effects, compare it to commonly used treatments, and collect information that will allow it to be used safely.
In Phase 4 trials, postmarketing studies delineate additional information, including the treatment's risks, benefits, and optimal use.
Before pharmaceutical companies start clinical trials on a drug, they conduct extensive preclinical studies."
We owe so much to those who have entered clinical trials. They've ventured into unknown territory so that we know how effective different treatments are and what the likely side effects will be. When you read the side effects listed on the information leaflets that comes in each medicine packet, just remember that a person suffered one or more of those side effects and it was most likely documented during a clinical trial.