So, in the San Antonio, we presented a study evaluating the SETER/PR assay as a predictor of extended letters of therapy benefit in the NSABP B42 trial. And B42 trial is a trial where a postmenopausal woman with ER-positive breast cancer, stage 1 to 3A, being disease free after five years of adjuvant endocrine therapy with an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor, they were randomized to five extended years of therapy for five years or placebo for five years...
So, in the San Antonio, we presented a study evaluating the SETER/PR assay as a predictor of extended letters of therapy benefit in the NSABP B42 trial. And B42 trial is a trial where a postmenopausal woman with ER-positive breast cancer, stage 1 to 3A, being disease free after five years of adjuvant endocrine therapy with an aromatase inhibitor or tamoxifen followed by an aromatase inhibitor, they were randomized to five extended years of therapy for five years or placebo for five years. And the study has shown significant benefit in disease-free survival, breast cancer-free interval, distant recurrence, but the benefit was modest in a range of about 2% to 3% absolute benefit, which underscores essentially the need to try to develop better predictors of risk of later recurrence and also predictors of benefit from extended endocrine therapy. And along those lines, we evaluated ERPR, which is a biomarker including 18 genes that are based on transcriptional activity of the estrogen receptor, as a predictor of extended endocrine therapy benefit in B42. So, we have two hypotheses. One was that the benefit from the discrimination of benefit by the said ERPR was focused mainly on the patients that were in the middle of the distribution curve of ERPR, between the interquartile limits of 1.1 and 2.1. And the low risk patients would not have benefit, low ERPR patients, would not have benefit from extended endocrine therapy because they were relatively insensitive to endocrine therapy. And the high end of the curve, the upper quarter, would benefit also not much because they were so sensitive that the first five years would have been enough. The second hypothesis we had is whether a cutoff in the middle, essentially, 1.5, higher than 1.5, would benefit more patients with extended endocrine therapy. So when we looked at the data, actually, when we looked at the first way, the middle 50% versus the quartiles 25% on each side, there was no significant benefit. But then when we looked at it according to the cut of 1.5, greater than 1.5, we saw significant benefit in the high ERPR and no significant benefit in the low ERPR, although the interaction was not statistically significant. And then we looked at it as a continuous variable, and as a continuous variable, as the ERPR went up, so did the benefit for extended years of therapy. And then we also looked at it according to different categories, less than 1.1, then 1.1 to 2.1 on the second category, and greater than 2.1. And in that categorization, we saw no benefit in the low end, good benefit about 35% reduction in the middle end, and then even more reduction in the higher end, over 2.1, almost with a 75% reduction. So essentially what we showed in the study is that ERPR can be used to estimate the extent of benefits from extended aromatase inhibitor therapy in patients that are received after five years of initial endocrine therapy.
