phase II trial
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phase II trial, phase 2 trial
A clinical trial to determine the potential effectiveness of a new drug. Generally, if at least 20% of the study subjects respond positively to it, e.g., achieve a 50% reduction in the total size of their measurable tumor, the new therapy will receive further testing. Another crucial statistic is the duration of response. Short-term responses may mean little in terms of survival; long-term responses indicate that the drug is benefiting some patients.
See also: trial