ASCO 2021: Novel CDK4/6 Inhibitor Plus Fulvestrant Focus of Phase III Trial in Advanced Breast Cancer
Posted: Tuesday, June 15, 2021
The novel CDK4/6 inhibitor dalpiciclib (SHR6390) plus fulvestrant may be a potential treatment for patients with hormone receptor–positive/HER2–negative (HR+/HER2–) advanced breast cancer. Binghe Xu, MD, of the National Cancer Center, Cancer Hospital, Chinese Academy of Medical Sciences, and colleagues showed the combination treatment significantly improved progression-free survival in this patient population, meeting its primary endpoint. The results were presented during the 2021 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract 1002).
The multicenter phase III DAWNA-1 trial recruited 361 patients with HR+/HER2– advanced breast cancer who relapsed or experienced disease progression on endocrine therapy. Patients were randomly assigned to receive either dalpiciclib with fulvestrant (n = 241) or a placebo with fulvestrant (n = 120). An interim analysis was conducted on November 15, 2020, as there were 162 events of disease progression or death.
After a median 10.5-month follow-up, patients who received dalpiciclib with fulvestrant had a significant improvement in progression-free survival compared with patients given placebo and fulvestrant (P < .0001). In addition, patients given dalpiciclib continued to benefit from treatment beyond initial study treatment based on the time to first subsequent chemotherapy (P < .0001). Although researchers had insufficient data to compute overall survival, at the time of analysis, there were 25 documented deaths.
The median duration of exposure was 9.4 months with dalpiciclib and 9.9 months with fulvestrant in the dalpiciclib/fulvestrant group. In contrast, patients in the placebo/fulvestrant group had a median duration of exposure of 6.1 months with fulvestrant.
The most common grade 3 or 4 adverse events observed in 3% or more of patients given dalpiciclib/fulvestrant included neutropenia and leukopenia. About 2.5% of patients given dalpiciclib/fulvestrant discontinued treatment because of adverse events compared with 3.3% of patients given placebo/fulvestrant.
Disclosure: For full disclosures of the study authors, visit coi.asco.org.
