There are three phases to a clinical trial and to clear up misconceptions people have regarding the phases-

First it has to be pointed out that clinical trials are limited in the number of available spaces. Once the target number of patients are accrued for those limited spaces, the trial is closed to further enrollment. A phase 1 trial is generally limited to 25 patients. Extensive safety testing has already been completed on animal models and a phase I study is the dose escalation phase. The study team has a target concentration for treatment and it is to determine if that concentration can be tolerated by the majority of patients or if a lower dose needs to be used. Participants are observed very closely….more so than when getting standard of care treatment. Every patient receives the experimental treatment. It is referred to as an open label, non-blinded, non-randomized study. Both oncologist and patient is aware the patient is receiving the drug. There is no control group. Patients in this group are the first to receive the drug whose general safety profile is known. Those that complete phase I are invited to continue on in a phase II trial to continue receiving the drug that showed benefit. In pancreatic cancer, time is of the essence. The disease can be aggressive and one’s physical condition can deteriorate and make them ineligible for a trial so that needs to be kept in mind.

Phase II trials expand the number of participants up to 125 and usually the number of sites are increased. A phase II trial may or may not have a control. If there is not a drug within the class of drug being tested-i.e., it is a new class of drug, then there is no control group. This was the scenario of the phase II trial I participated in so I received the drug. Being open label, I and the oncologist knew I was receiving the medication. Otherwise it there is a control group, participants are randomly assigned by computer to the test cohort or the control group receiving the current standard of care treatment to be compared with. This phase can be randomized as explained as well as be open label, single blind (patient unaware of being given the treatment but oncologist is aware), or double blind (neither participant or oncologist knows until conclusion of the study when it is unblinded).

Phase III is the largest study with hundreds to thousands of participants in many locations that can be international as well as domestic. These are randomly assigned to a study arm or control arm and can be unblinded or blinded. So if one thinks they are better off waiting for a phase III trial because there is more data on how patients tolerated the treatment, you have the potential of not qualifying for the trial because your health status changed while waiting or the computer randomly assigns the participant to a control cohort.

I had an aggressive form of pancreatic cancer. Time was of the essence. It took 14 months until an ideal trial opened. It happened to be phase II with only 25 positions available at the site where I wanted to participate. There was no way to predict if I would remain healthy to qualify so I needed to act quickly while the opportunity was available. I would have joined the phase I trial if it had been available to see if I could derive benefit as soon as possible. I was not going to risk my life waiting for a phase III trial when an earlier opportunity presented itself. That decision paid off….I am an 11 year survivor of metastatic disease to the liver and after achieving NED am considered cured. I hope I shed some light on clinical trial phases and their characteristics.