Changes in selected haematological parameters associated with JAK1/JAK2 inhibition observed in patients with rheumatoid arthritis treated with baricitinib
RMD Open, vol. 6, pp. e001370
Abstract
Objective To characterise changes in selected haematological parameters following once-daily oral baricitinib dosing. Methods Data were pooled from eight randomised clinical trials (four phase 3, three phase 2, one phase 1b) and one long-term extension. Changes in haematological parameters were evaluated up to 128 weeks (N=2387); overall safety of baricitinib was assessed up to 6 years (N=3492). Results Mean absolute neutrophil counts decreased (−1.36×109/L) within 1 month, followed by stabilisation within the normal reference range through week 128. The incidence of serious infections was not elevated in patients with neutropenia during the 24-week placebo-controlled period. Mean lymphocyte counts increased (+0.30×109/L) within 1 month, then decreased to baseline (weeks 12–24). Mean platelet counts increased at week 2 (+51×109/L), then decreased towards baseline. Overall, mean haemoglobin concentrations decreased (−0.12 mmol/L), then returned to baseline; however, reduced baseline haemoglobin concentrations observed in the highest baseline high-sensitivity C reactive protein quartile increased over time. Permanent drug discontinuation occurred due to laboratory abnormalities related to neutrophil count in 8 (0.2%), lymphocyte counts in 6 (0.2%), platelet counts in 8 (0.2%), and haemoglobin levels in 16 (0.5%) of all baricitinib-treated patients (N=3492 with 7993 total person-years of exposure). Conclusions Moderate decreases in neutrophils were seen during baricitinib treatment; however, serious infection was uncommon in patients with neutropenia. Transient increases were observed in lymphocytes and platelets, which returned to baseline over time. Changes in haemoglobin concentration were generally small. Haematological abnormalities seldom led to drug discontinuation.
Authors 15
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Jonathan Kay corresponding
University of Massachusetts Chan Medical School · UMass Memorial Medical Center
Affiliation as printed
Department of Population and Quantitative Health Sciences, University of Massachusetts Medical School, Worcester, Massachusetts, USA
Division of Rheumatology, Department of Medicine, UMass Memorial Medical Center, Worcester, Massachusetts, USA
Division of Rheumatology, Department of Medicine, University of Massachusetts Medical School, Worcester, Massachusetts, USA
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Tokyo Women's Medical University
Affiliation as printed
Institute of Rheumatology, Tokyo Women’s Medical University, Tokyo, Japan
Institute of Rheumatology, Tokyo Women's Medical University, Tokyo, Japan
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Affiliation as printed
Eli Lilly and Company, Indianapolis, Indiana, USA
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Affiliation as printed
Eli Lilly and Company, Indianapolis, Indiana, USA
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Affiliation as printed
Syneos Health, Morrisville, North Carolina, USA
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Affiliation as printed
Eli Lilly and Company, Indianapolis, Indiana, USA
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Affiliation as printed
Eli Lilly and Company, Indianapolis, Indiana, USA
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Affiliation as printed
Eli Lilly and Company, Indianapolis, Indiana, USA
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Affiliation as printed
Eli Lilly and Company, Indianapolis, Indiana, USA
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Affiliation as printed
Eli Lilly and Company, Indianapolis, Indiana, USA
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Affiliation as printed
Rebecca MacDonald Centre for Arthritis and Autoimmune Disease, Mount Sinai Hospital, Toronto, Ontario, Canada
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Amsterdam University Medical Centers
Affiliation as printed
Department of Rheumatology and Clinical Immunology, Amsterdam Universitair Medische Centra, Amsterdam, The Netherlands
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Columbia University Irving Medical Center · Columbia University
Affiliation as printed
Division of Rheumatology, Department of Medicine, Columbia University College of Physicians and Surgeons, New York City, New York, USA
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Leiden University Medical Center
Affiliation as printed
Department of Rheumatology, Leids Universitair Medisch Centrum, Leiden, The Netherlands
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Affiliation as printed
Division of Rheumatology, Department of Medicine, Albany Medical College, Albany, New York, USA
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