Dataset Information

A phase 1 study of dalpiciclib, a cyclin-dependent kinase 4/6 inhibitor in Chinese patients with advanced breast cancer.

ABSTRACT:

Background

Dalpiciclib (SHR6390) is a novel inhibitor of cyclin-dependent kinase 4/6 which demonstrated promising anti-tumor potency in preclinical models. This first-in-human study was conducted to evaluate the tolerability, pharmacokinetics, safety, and preliminary antitumor activity of dalpiciclib in patients with advanced breast cancer (ABC).

Methods

In this open-label, phase 1 study, Chinese patients who had failed standard therapy were enrolled to receive oral dalpiciclib in 3 + 3 dose-escalation pattern at doses of 25-175 mg. Eligible patients were given a single-dose of dalpiciclib in week 1, followed by once daily continuous doses for 3 weeks, and 1 week off in 28-day cycles. Based on the tolerability, pharmacokinetics, and activity data revealed from the dose-escalation phase, three dose cohorts were selected to expand to 8-10 patients. The primary endpoints were maximum tolerated dose (MTD) and pharmacokinetics.

Results

Between Apr 15, 2016 and Dec 21, 2018, 40 patients were enrolled; all were diagnosed of hormone receptor-positive and HER2-negative ABC. Dalpiciclib 100 mg, 125 mg, and 150 mg cohorts were expanded to 10 patients. No dose-limiting toxicity was observed and the MTD was not reached. Adverse events (AEs) of grade 3 or 4 were observed in 22 (55.0%) of 40 patients, being neutropenia (52.5%), leukopenia (35.0%), thrombocytopenia (5.0%), and hypertension (2.5%). No serious AEs were reported. At the doses of 50-175 mg, steady state areas under the concentration-time curve and peak concentration increased almost proportionally with dose. The disease control rate (DCR) was 62.5% (25/40, 95% CI: 45.8-77.3). Two patients (5%; 125 mg and 150 mg cohorts) achieved partial response, with responses lasting 169 and 356+ days, respectively. Among the three expansion cohorts, the 150 mg cohort had the numerically highest DCR of 80.0% (95% CI: 44.4-97.5) and longest median progression-free survival of 8.4 months (95% CI: 2.1-not reached).

Conclusions

Dalpiciclib showed acceptable safety profile and dose-dependent plasma exposure in Chinese patients with ABC. The recommended phase 2 dose was 150 mg. Preliminary evidence of clinical activity was observed, which warrants further validation.

Trial registration

ClinicalTrials.gov identifier: NCT02684266 . Registered Feb 17, 2016.

SUBMITTER: Zhang P

PROVIDER: S-EPMC8042970 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:OBJECTIVE:To review palbociclib, a novel small-molecule inhibitor of cyclin-dependent kinases 4 and 6, and its current place in therapy for the treatment of hormone receptor (HMR)-positive, human epidermal growth factor receptor 2 (Her2)-negative advanced breast cancer. STUDY SELECTION AND DATA ABSTRACTION:Four phase I trials, 2 phase II trials, and 1 phase III trial were identified from May 2004 to May 2015 using PubMed, American Society of Clinical Oncology (ASCO) abstracts, and European Society of Medical Oncology (ESMO) abstracts. DATA SYNTHESIS:In the first-line setting, the phase II PALbociclib: Ongoing trials in the Management of breast cAncer (PALOMA)-1 trial randomized patients to receive letrozole alone or letrozole plus palbociclib 125 mg daily for 3 weeks, followed by 1 week off, as initial therapy for advanced breast cancer. The investigator-assessed median progression-free survival (PFS) was 20. 2 months for the combination versus 10.2 months for letrozole alone (hazard ratio [HR] = 0.488; 95% CI = 0.319-0.748; 1-sided P = 0.0004). The ensuing Food and Drug Administration approval of palbociclib was given a "breakthrough therapy" designation, where preliminary evidence suggests substantial improvement over existing therapies for a serious or life-threatening disease. A confirmatory phase III trial, PALOMA-2, is under way. In patients who were previously treated with endocrine therapy for advanced breast cancer, the phase III PALOMA-3 trial randomized patients to fulvestrant plus palbociclib versus fulvestrant plus placebo. The investigator-assessed median PFS at the time of a preplanned analysis was 9.2 months with palbociclib-fulvestrant compared with 3.8 months with placebo-fulvestrant (HR = 0.42; 95% CI = 0.32-0.56; P < 0.001). CONCLUSIONS:Palbociclib, the first-in-class CDK4/6 inhibitor, significantly extended PFS in combination with endocrine therapy in the first and subsequent lines of treatment for HMR-positive, Her2-negative advanced breast cancer.