Dana-Farber Cancer Institute's Dr. Sara Tolaney presented a subgroup analysis of the ASCENT-04 study based on biomarkers. Across all subgroups, patients who received sacituzumab govitecan plus pembro as first-line therapy had longer progression-free survival compared to standard therapy.ant and potentially meaningful improvements in overall survival. Strategies to improve adoption of ePRO-based symptom management may be warranted.
So, at ASCO this year, we're presenting the results of the biomarker analysis from the ascent 04 trial. This is a randomized phase 3 trial for patients who have previously untreated metastatic triple negative breast cancer, that is PDL1 positive. And in this trial, patients had been randomized to receive stuzumab govetecan plus pembrolizumab or chemotherapy, a physician's Choice plus pembrolizumab. And the trial did offer and provide crossover treatment to the chemotherapy Pembro arm with SG at time of disease progression. We had previously seen the primary endpoint from this trial, which was progression-free survival by blinded independent central review, and had seen that there was a statistically significant improvement in PFS for SG plus Pembro compared to chemo Pembro with a hazard ratio of 0.65. At ASCO this year we have looked now at biomarker data where we centrally looked at trope 2 expression by immunohistic chemistry. We also did whole exome sequencing of tissue to determine tumor BRCA mutation status, and we also centrally looked at HER2 expression and we looked to see if any of these biomarkers impacted efficacy. The trope 2 analysis broke down trope 2 expression into quartiles, and what we saw was that across all four quartiles, the benefits of SG Pembro compared to chemo plus Pembra were consistently seen. It is interesting to note though that the absolute PFS for SG Pembro was higher in the. To higher quartiles, um, although I will interpret this with a bit of caution given very wide confidence intervals around these estimates, we also saw that benefits for SG Pembro compared to chemo Pembro were seen for both tumor BRCA mutant and tumor BRCA wild type patients. And we also saw similarly that benefits were seen irrespective of degree of HER2 expression. So whether someone had a tumor that was HER2 IC 0 or HER2 low, benefits for SG Pembro versus chemo Pembro were consistently seen. So overall, I will say that this biomarker analysis really suggested that across all subsets, uh, benefit for SG plus Pembro was seen compared to chemotherapy plus pembrolizumab. There are other biomarker analyses that are ongoing that will be presented at future congresses.
