Risk factors associated with palbociclib-induced neutropenia in patients with metastatic breast cancer.

BACKGROUND: Neutropenia is the most common adverse event with palbociclib, an oral cyclin-dependent kinase 4/6 inhibitor, with grade 3/4 neutropenia occurring in up to 67% of patients in phase III trials evaluating this agent in metastatic breast cancer. This retrospective chart review assessed characteristics of patients on palbociclib to evaluate for risk factors in the development of grade 3/4 neutropenia. PATIENTS AND METHODS: Patients with metastatic breast cancer who received palbociclib were included. Patient demographics collected included age, gender, race, body mass index, breast cancer treatment history, palbociclib starting dose, baseline absolute neutrophil count, baseline platelet count, concomitant hormonal therapy, concomitant use of denosumab, and use of concomitant strong CYP3A4 inhibitors/inducers. Events of interest occurring within 30 days of initiation of palbociclib were also noted including antibiotic and corticosteroid use, mucosal conditions, open wounds, or surgery. The incidence and potential risk factors for grade 3/4 neutropenia in the first 6 months of treatment were analyzed. RESULTS: A total of 257 patients were included in the analysis with 206 patients (80.2%) and 139 patients (54.1%) experiencing all-grade neutropenia and grade 3/4 neutropenia, respectively. Multivariate analysis found baseline myelosuppression and recent antibiotic use to be independent predictors of grade 3/4 neutropenia. Normal weight patients had an increased risk for grade 3/4 neutropenia compared to obese patients by multivariate analysis. CONCLUSION: The results of this study showed baseline myelosuppression and recent antibiotic use within 30 days of palbociclib initiation were predictive of a higher incidence of grade 3/4 neutropenia. Obese patients were less likely to develop grade 3/4 neutropenia compared to normal weight patients.

Comparative Utilization and Efficacy of Thrombopoietin Receptor Agonists in Relapsed/Refractory Immune Thrombocytopenia.

BACKGROUND: The thrombopoietin (TPO) agonists, eltrombopag and romiplostim, stimulate the production of platelets and offer an effective treatment option in relapsed/refractory immune thrombocytopenia (ITP). Recently published 2019 ITP guidelines recommend the TPO agonists as second-line therapy following corticosteroids; however, little data offer insights into comparative efficacy and tolerability. STUDY QUESTION: Is there a difference in the efficacy between romiplostim and eltrombopag in relapsed/refractory ITP? STUDY DESIGN: We conducted a single-center, retrospective chart review of patients with ITP treated with romiplostim or eltrombopag. MEASURES AND OUTCOMES: The primary objective was a sustained platelet response, defined as platelets greater than 50,000/µL in more than 66% of clinic visits over a 6-month period. Secondary objectives sought to evaluate response to and tolerability of TPO agonists. RESULTS: The study included 107 consecutive patients, 67 (63%) on romiplostim and 40 (37%) on eltrombopag. Previous corticosteroids and rituximab were used in 95% and 50% of patients, respectively. There was no difference identified in platelet responses between the TPO-RAs, 72% romiplostim versus 65% eltrombopag (P = 0.520). In addition, no differences were identified in secondary measures of response. CONCLUSIONS: In our experience with romiplostim and eltrombopag for ITP, we did not identify a difference in the efficacy of these agents. Further larger and prospective evaluations should be considered.

Ibrutinib treatment via alternative administration in a patient with chronic lymphocytic leukemia and dysphagia.

INTRODUCTION: Ibrutinib is a small molecule inhibitor of Bruton's tyrosine kinase indicated for the treatment of a variety of B-cell malignancies including chronic lymphocytic leukemia, mantle cell lymphoma, marginal zone lymphoma, and Waldenstrom's macroglobulinemia. These indolent hematologic malignancies are considered diseases of the elderly, a population that may have dysphagia leading to difficulty swallowing tablets and capsules. Ibrutinib is currently not available in a liquid oral dosage form. We report the utilization and clinical outcomes associated with alternative administration of ibrutinib capsules in a patient with chronic lymphocytic leukemia and significant dysphagia. CASE REPORT: An 86-year old female requiring chronic lymphocytic leukemia-directed therapy due to a rising absolute lymphocyte count and worsening, transfusion-dependent anemia with a past medical history of dementia and dysphagia, was initiated on ibrutinib. MANAGEMENT & OUTCOME: Due to the patient's significant inability to swallow, ibrutinib capsules were administered via an alternative method by opening them and sprinkling onto soft food or applesauce. With ibrutinib therapy, the patient has had a significant clinical response in her chronic lymphocytic leukemia as evidenced by her decreased absolute lymphocyte count and achieving transfusion independence with improvements in hemoglobin. DISCUSSION: Ibrutinib administration via this alternative method resulted in an initial clinical response in the treatment of our patient's chronic lymphocytic leukemia as evidenced by a decreasing absolute lymphocyte count and improved anemia that achieved transfusion independence. The patient has maintained this response to therapy after approximately 1 year at the time of manuscript preparation.