Dalpiciclib (SHR-6390) hydrochloride is an orally active and highly selective inhibitor of CDK4 and 6 with IC50 values of 12.4 nM and 9.9 nM, respectively[1][2]. Dalpiciclib hydrochloride shows antitumor activity against breast cancer and esophageal squamous cell carcinoma[1][2][3][4].

Dalpiciclib hydrochloride (0-4 μM, 72 h) inhibits cell proliferation in a dose-dependent manner[3].Dalpiciclib hydrochloride (0-10 μM, 6 d) inhibits the proliferation of retinoblastoma-positive tumor cell lines[4].

Dalpiciclib hydrochloride (oral gavage; 150 mg/kg; once weekly; 3 weeks) shows antitumor activity against ESCC xenografts[3].Dalpiciclib hydrochloride combined with Paclitaxel (PTX) or Cisplatin (CDDP) offer synergistic inhibitory effects in ESCC xenografts[3].Dalpiciclib hydrochloride (oral gavage; 37.5 mg/kg, 75 mg/kg, 150 mg/kg; once daily; 30 days) shows antitumor activity in human xenograft models [4].

[1]. Jose Manuel Perez-Garcia, et al. Perez-Garcia JM, Cortes J, Llombart-Cussac A. CDK4/6 inhibitors in breast cancer: spotting the difference. Nat Med. 2021 Nov;27(11):1868-1869.
[2]. Pin Zhang, et al. A phase 1 study of dalpiciclib, a cyclin-dependent kinase 4/6 inhibitor in Chinese patients with advanced breast cancer. Biomark Res. 2021 Apr 12;9(1):24.
[3]. Jiayuan Wang, et al. CDK4/6 inhibitor-SHR6390 exerts potent antitumor activity in esophageal squamous cell carcinoma by inhibiting phosphorylated Rb and inducing G1 cell cycle arrest. J Transl Med. 2017 Jun 2;15(1):127.
[4]. Fei Long, et al. Preclinical characterization of SHR6390, a novel CDK 4/6 inhibitor, in vitro and in human tumor xenograft models. Cancer Sci. 2019 Apr;110(4):1420-1430.