Most studies to date that show efficacy with ruxolitinib in this setting have been in adult patients.
A retrospective study boasts high response rates and manageable toxicity associated with ruxolitinib in children with steroid-refractory graft-versus-host-disease (GvHD) following hematopoietic stem cell transplantation, suggesting the JAK1/2 inhibitor is a viable second-line treatment option for these patients.
To date, most studies showing promising efficacy with ruxolitnib in this setting have been in adult patients. Ruxolitinib is approved for steroid-refractory acute GvHD (aGvHD) in patients over the age of 12 years. In total, there were 19 children included in the current study, 12 of which were under the age of 12 years.
The study showed overall response rates of 87% among patients with aGvHD and 91% among patients with chronic GVHD, with complete response (CR) rates of 37% and 8.3%, respectively. The researchers note that the lower CR rate among patients with cGvHD should be further contextualized in order to adjust expectations for response to ruxolitinib treatment among these patients.
“Interestingly, we observed response in 43% of gut steroid-refractory aGvHD, being grade IV in 2 of them,” noted the researchers. “Similar successful data was observed in cGvHD lung involvement with 40% of CR, although to date data regarding the use of ruxolitinb in bronchiolitis obliterans are scarce, Schoettler et al published in 2019 the good response obtained in a small cohort of pediatric patients.”
Three in 4 patients (76.4%) were alive at 2 years, and there was no observed aGVHD or cGVHD reactivation following discontinuation of treatment.
Throughout treatment, 36% of patients experienced infections caused by viruses, 31% experienced infections caused by bacteria, and 10% experienced infections caused by fungi. The researchers noted that the incidence of infections was higher than expected, especially for bacterial infections.
Liver toxicity was reported in most patients, with half of patients experiencing Grade 3 toxicity. Ruxolitinib treatment was interrupted in 4 patients because of liver toxicity, as well as hematologic toxicity and infectious complications. Hematologic toxicity in particular has been well documented in other studies and reports, with a higher rate of thrombocytopenia reported.
“An important fact to take into account is that, due to the lack of PK direct dosing studied for ruxolitinib in children under 12 years of age, starting dose of ruxolitinib was decided according to previous reports. This factor could have influenced the responses and toxicity observed.”
Mozo Y, Bueno D, Sisinni L, et al. Ruxolitinib for steroid-refractory graft versus host disease in pediatric HSCT: high response rate and manageable toxicity.J Pediatr Hematol Oncol. 2021;38(4):331-345.