Task: Text Simplification
Input (English): this quantitative measure indicates how much of a particular drug or other substance -lrb- inhibitor -rrb- is needed to inhibit a given biological process -lrb- or component of a process , i.e. an enzyme , cell , cell receptor or microorganism -rrb- by half.
Output (English): this quantitative measure indicates how much of a drug or other substance is needed to inhibit a biological process by half.