This is a twist on endocrine therapy. We’ve heard a lot about SERDs or selective estrogen receptor degraders. This is a SERCA, so a selective estrogen receptor covalent antagonist. And we presented data at ASCO 2021 for 94 patients that were treated at the 450 milligram dose. This was really a heavily pretreated patient population and I encourage everyone to kind of look at the patient characteristics when comparing the SERDs and the SERCAs across studies, because they’re not all quite created equal...
This is a twist on endocrine therapy. We’ve heard a lot about SERDs or selective estrogen receptor degraders. This is a SERCA, so a selective estrogen receptor covalent antagonist. And we presented data at ASCO 2021 for 94 patients that were treated at the 450 milligram dose. This was really a heavily pretreated patient population and I encourage everyone to kind of look at the patient characteristics when comparing the SERDs and the SERCAs across studies, because they’re not all quite created equal. 85% of these patients had seen prior CDK4/6 which as we know is now the standard. 72 or about three quarters of our patients had received a prior fulvestrant. A third of patients had seen more than four lines in the metastatic setting and half of our patients at seen chemotherapy.
And so what we saw with this oral therapy is a median progression of over five months that broke down to 17% of patients having a partial response and 43% of patients having stable disease. For a clinical benefit rate with the more conservative definition of CRs, PRs, plus stable disease of at least six months, duration of 40%. And so I think that we’re going to hear more about SERDs and SERCAs, et cetera, particularly post CDK4/6. Certainly also has the possibility for these agents to go in with CDK4/6 inhibitors. But we know for patients that are highly dependent on estrogen signaling that even post aromatase inhibitor and CDK4/6 we need other very effective drugs in this space.