Median weekly pollen counts and symptom, rescue-medication, and visual-analog scores for the initial placebo trial (1989) and for the subsequent three-year trial (1993 through 1995)

Analysis of the area under the curve with the Mann-Whitney U test revealed no significant differences between the maintenance group and the discontinuation group; the median scores in both of these groups were markedly lower than those in the control group. For comparison, results are also shown for the initial placebo-controlled trial of immunotherapy (1989). Tick marks on the X axes indicate one-week intervals. Data for 1989 are from Varney et al.^[1]