Discussion
Our study showed that ruxolitinib therapy in children with TM
accompanied by prominent features of IE leads to considerable reduction
of the spleen volume and the RBC transfusion requirement. This
correlates with significant decrease in sTfR concentration and tendency
to declining of erythrocyte progenitor in the bone marrow. The maximum
effect of IE suppression was achieved mostly after the first 3 months of
ruxolitinib therapy. It appears that therapeutic effect of ruxolitinib
was dose-dependent as clinical and laboratory features of IE rapidly
returned to initial after ruxolitinib dose reduction.
The outcomes of HSCT were favorable in 7 out of the 8
“difficult-to-transplant” patients with TM. We suggest that IE which
is one of the main risk factors potentially leading to primary and
secondary severe graft failure and immune suppression may both impact on
the favorable engraftment rate. There are two important limitation
factors of ruxolitinib therapy, one is rapid loss of response after drug
interruption and another is potentially severe AE with long-term use.
Thus, short-term application of ruxolitinib in patients with TM and
pronounced IE can be used safely and seems to be a promising approach
for preparing pediatric patients with TM and pronounced IE for HSCT.