Open AccessPB1972 RIBOCICLIB INDUCES MACROCYTOSIS IN THERAPEUTIC DOSES: CHARACTERIZATION OF OUTCOME
Author(s) -
Alves S.,
Alves S.
Publication year - 2019
Publication title -
hemasphere
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.677
H-Index - 11
ISSN - 2572-9241
DOI - 10.1097/01.hs9.0000566384.33696.dd
Subject(s) - medicine , mean corpuscular volume , oncology , macrocytosis , anemia , neutropenia , breast cancer , adverse effect , gastroenterology , cancer , hemoglobin , chemotherapy
Background: Ribociclib is a small molecule that selectively inhibits cyclin‐dependent kinases 4 and 6, blocking the phosphorylation of retinoblastoma protein and inducing of G1 phase arrest hence having an important role in the regulation and prevention of cell‐cycle progression. The project OncoDynamics aims to explore possible correlations between therapeutic doses of ribociclib for treatment of breast cancer and other therapies with several analytic biomarkers and clinical data. Adverse events of CDK 4/6 inhibitors are mostly hematologic being neutropenia the most frequent followed by anemia and thrombocytopenia as it is the case of palbociclib which has been recently described as associated with macrocytic, dysplastic anemia. Aims: This study aims to characterize the outcome of macrocytosis evident in our patients treated with ribociclib in therapeutic doses for treatment of breast cancer. Methods: This study is integrated in the OncoDynamics project and is a prospective, unicentric cohort study with patients treated for metastatic breast cancer with ribociclib plus letrozole, each patient registered as digital case report form and evaluated data of mean corpuscular volume (MCV), hemoglobin (Hg) and red cell distribution width (RCDW) for descriptive analyses. Results: Of the 7 patients with breast cancer treated with ribociclib (14,8%) with a follow up period ranging from 3 to 18 months, 4 patients (57,1%) had a sustained rise of the mean corpuscular volume (MCV > 97 fL), Hg ranging from 8,8 to 13,5 g/dL and RCDW from 12,7 to 20,9 CV%. Summary/Conclusion: We found this macrocytosis to be related to the treatment with ribociclib in therapeutic doses and in literature the correlation between CDK 4/6 inhibitors and macrocytosis has been described in relation to palbociclib. Clinical evolution of these patients is under evaluation. We aim to extend this study and to explore the inherent mechanism of action of ribociclib regarding anemia and macrocytosis.