At ASCO this year we saw further data come out from the ASCENT-03 trial. This was a randomised phase III study comparing sacituzumab govitecan to chemotherapy in patients with metastatic triple-negative breast cancer in the first-line setting that are not candidates for a checkpoint inhibitor. We had seen the data regarding progression free survival from this trial, it was presented at ESMO last year, where we saw that sacituzumab led to a significant and clinically meaningful improvement in progression free survival compared to chemotherapy with a hazard ratio of 0.62. So this data really suggested that sacituzumab could become a new standard of care for patients with previously untreated metastatic triple-negative breast cancer.

At ASCO this year we saw data come regarding PFS2 from this trial. So, just as a bit of background, in this trial the primary endpoint for ASCENT-03 was progression free survival by blinded independent central review and a key secondary endpoint was overall survival. But at ASCO exploratory endpoints were presented that looked at PFS2, time to first subsequent therapy and time to second subsequent therapy. This was really done to better understand the longer-term impact of first-line sacituzumab in a setting where a trial had crossover that was offered and provided to patients in the control arm and in the setting of not having mature overall survival data because at the time of the primary analysis the survival data was immature with just about 37% of survival events having occurred. So we thought that presenting PFS2 could be helpful to understand longer-term impact of first-line sacituzumab.

What we saw was that PFS2 was, indeed, prolonged with sacituzumab compared to chemotherapy with a PFS2 median at 18.2 months for sacituzumab and 14 months for chemotherapy with a hazard ratio of 0.7. What I thought was quite striking was this 30% reduction in PFS2 events occurred despite a very high rate of crossover from chemotherapy to sacituzumab within the control arm, where we saw that about 82% of patients, in essence, were getting an ADC in the second-line setting. So a very high rate of crossover that occurred and yet you’re still seeing a more prolonged PFS2 with the SG arm.

So these data really just support the benefits of using sacituzumab govitecan in the first-line setting for our patients with metastatic triple-negative breast cancer and hopefully we will see near-term approval for this.