Does joining one cancer clinical trial disqualify you from joining another trial?

Participating in one clinical trial does not necessarily disqualify you from future trials, as long as you meet the future study criteria. Many people participate in more than one clinical trial over time. Rules for trial participation do take into consideration therapy that you have received prior to joining a trial, and a prior treatment that you have received—either standard or experimental—might make you ineligible. If you already know you might be interested in a specific trial sometime in the future, check with your doctor or clinical trial site to see if the treatment decisions you make today could get in the way later. For the most part, however, many other clinical trials are available, and even if one particular study is off limits to you, another is likely to become available.