Dr. Tolaney: So, at ESMO this year, we saw results from the MONARCH 3 study. This was a randomized phase III trial that looked at adding abemaciclib to an aromatase inhibitor in a first-line metastatic setting among patients with hormone-receptor-positive, HER2-negative breast cancer.
And I think many of us were eagerly awaiting these data because we had seen prior data come out from the MONALEESA study, suggesting that adding ribociclib to either an aromatase or fulvestrant in the upfront setting did lead to survival benefit. And then, we've also seen negative data from the PALOMA-2 study suggesting adding palbociclib to an aromatase inhibitor did not lead to overall survival benefit. So, everyone's been wondering, well, what about abemaciclib, since we had the palbo and ribo data out, but not yet the abema data.
Clinically meaningful overall survival trend with addition of abemaciclib
And so, at ESMO, they presented data from the second interim analysis of overall survival from MONARCH 3. And while there was not a statistically significant benefit in overall survival, there was a clinically meaningful trend in overall survival with a 12.8-month difference between the two arms, favoring abemaciclib. And when you also looked at outcomes amongst patients with visceral metastases, there was about a 16-month difference in overall survival, again favoring abemaciclib.
So, I think, again, while this study did not reach statistical significance, it was at the time of a second interim analysis, and so, there is likely to be a subsequent overall survival analysis that will be presented in 2023, and hopefully, that one will technically reach statistical significance. But at this time, I think these data are clinically meaningful and I think allow us to think about having choice of CDK4/6 inhibition when selecting one to be given in combination with endocrine therapy in the first-line setting.