Neutropenia (Low White Blood Cell Count)

This study is a multicenter, single-arm, open-label Phase II exploratory clinical trial designed to evaluate whether prophylactic use of leucogen can reduce the incidence of Grade 3 or higher neutropenia in early-stage HR+/HER2- breast cancer patients receiving ribociclib combined with endocrine therapy. The study plans to enroll 97 patients using a Simon two-stage design, with the primary endpoint being the incidence of severe neutropenia within 4 treatment cycles (4 months) after initiation. Secondary endpoints include the incidence of all-grade neutropenia, febrile neutropenia, ribociclib treatment intensity, and safety. The study will systematically assess the preventive efficacy and safety of leucogen to provide a basis for subsequent Phase III randomized controlled trials.

This is a prospective observational study designed to assess the prevalence of the Duffy null phenotype (associated with ethnic neutropenia) in neonates born at Kaplan Medical Center. Blood samples will be collected from umbilical cords (non-invasively) to evaluate Duffy antigen expression. Data on ethnicity, perinatal factors, and routine blood counts at 9-12 months (when available) will also be collected to correlate phenotype with absolute neutrophil count (ANC).