Neoadjuvant pyrotinib plus trastuzumab, dalpiciclib, and letrozole for triple-positive breast cancer: A pilot trial.

• DOI: 10.1200/jco.2023.41.16_suppl.e12603
• Publication Date: 2023-06-04T14:09:31Z
• Authors: Jinqi Xue; Nan Niu; Shuo Wang; Guanglei Chen; Fang Qiu; Yi Zhao; Fei Xing; Xinyu Zheng; Wei Tu; Ke Li; Hai Zhao; Meiyue Tang; Qianshi Xu; Chao Liu; Yafei Zhao; Xiaofan Jiang; Shiwen Huo; Zheng Pang; Dianlong Zhang; Caigang Liu
• Keywords: Letrozole; Regimen; Neoadjuvant Therapy; Clinical endpoint

e12603 Background: Our previous MUKDEN 01 study showed a promising total pathological complete response (tpCR) rate of 30.4% with neoadjuvant pyrotinib plus dalpiciclib (cyclin dependent kinase 4/6 inhibitor) and letrozole in patients triple-positive breast cancer (TPBC), but the efficacy still needs improvement. This pilot explored safety adding trastuzumab to this regimen TPBC. Methods: Patients received five 28-day cycles (320 mg once daily), (125 daily on days 1-21) (2.5 six 21-day (8 mg/kg loading dose followed by 6 maintenance day 1), surgery. The primary endpoint was tpCR (ypT0/is, ypN0) rate. Secondary endpoints were objective (ORR), (bpCR; ypT0/is) rate, residual burden (RCB), change Ki-67 level from baseline surgery, safety. Results: Between February 16, 2022 June 2, 2022, 12 enrolled. Seven (58%; 95% CI, 27.7-84.8) achieved bpCR. RCB 0-I 75% (95% 46.8-91.1%). ORR 92% 64.6-98.5%). Mean significantly reduced 45.0% 19.5% - 70.5%) at 17.2% 0.7% 33.7%) after therapy (P<0.05). most common grade 3 adverse events diarrhea (4 [33%]) decreased neutrophil count (3 [25%]). No 4 or treatment-related deaths occurred. Conclusions: four-drug shows TPBC, an acceptable profile. results warranted further validation. Clinical trial information: NCT05228951 .