Ruxolitinib applied twice daily did not appear to impact hematologic parameters in any clinically meaningful way, according to a new study. 

"In two randomized phase 3 studies (TRuE-AD1 and TRuE-AD2) evaluating ruxolitinib (Janus kinase [JAK]1/JAK2 inhibitor) cream in adults and adolescents with mild to moderate atopic dermatitis (AD), low plasma concentrations of ruxolitinib were observed with no clinically meaningful reductions in laboratory parameters for hemoglobin, platelets, or neutrophils," the authors wrote in the abstract. 

The double-blind, vehicle-controlled trial included 330 children randomized to receive 0.75% ruxolitinib cream, 1.5% ruxolitinib cream, or a vehicle cream twice daily for 8 weeks. Hematologic parameters, including hemoglobin, platelets, and neutrophils, were taken at baseline, Week 2, and Week 8. Plasma concentrations of ruxolitinib were assessed at Weeks 2 or 4 and Week 8.

According to the results, there were no clinically meaningful changes in hematologic parameters with either strength of ruxolitinib cream. The mean percentage changes from baseline for hemoglobin were between -1.0% to 0.6%, for platelets between 2.8% to 6.9%, and between -2.1% to 10.3% for neutrophils. Additionally, ruxolitinib plasma concentrations remained below the myelosuppression threshold of 281 nM. Only two patients experienced neutropenia (one in the 1.5% ruxolitinib group and one in the vehicle group).

“The goal of this study was to determine if hematologic changes are observed with ruxolitinib cream in children aged 2-11 with mild to moderate AD," co-author Linda Stein Gold, MD, director of clinical research and division head of dermatology at Henry Ford Health System in Detroit, MI, told Practical Dermatology. "There were no clinically meaningful changes in hematologic parameters with 8 weeks of twice daily ruxolitinib cream (0.75% or 1.5%).  Patients treated between 3-20 % body surface area. Mean plasma concentrations of ruxolitinib cream remained below a threshold associated with bone marrow myelosuppression with both strengths of ruxolitinib cream across age subgroups.”

Results from this analysis were presented at the Society for Pediatric Dermatology (SPD) 49th Annual Meeting in Toronto.