DISCUSSION:
Pediatric cases of BPDCN has been defined increasingly since 2008 with
the report of World Health Organization as a part of AML(4). But lack of
experience effects proper diagnosis and optimal treatment.
In 2010, Jegalian et al defined diagnostic features and clinical
implications for children and they concluded that BPDCN is less
aggressive for pediatric age group and high risk ALL chemotherapy is
effective for treatment. Furthermore stem cell transplantation can be a
choice in second complete remission(5). In adults; stem cell
transplantation is being used as a consolidation therapy due to
aggressiveness of the disease(6). Later than, skin involvement was
defined as an indicative finding for aggressiveness of the disease in
children(7). There is still no consensus about the curative treatment of
BPDCN in children.
Tagraxofusp-erz is a recombinant cytotoxin consisting human IL-3 fused
to a truncated diphteria toxin and approved for BPDCN (for patients age
above 2 years and older) since December 2019. (1,8). There are a handful
of pediatric patients who were treated with tagraxofusp-erzs in
literature and our patient had treatment for two cycles and reached a
remission and a bridge to stem cell transplantation. To obtain
remission, we also preferred to add a bcl-2 inhibitor; venetoclax with
potential benefit for remission which was successfully applied in
literature to a 77 years old patient with comorbidities without
significant adverse effect(9). The literature emphasize the risk of
transient remission for both adults and children yet for patients in
second remission, tagraxofusp is advised as an optimal therapy to
decrease residual disease and bridge to stem cell transplantation(6).
Our patient had relapsed six months after stem cell transplantation.
Considering previous toxicities, therapy changed to a venetoclax and
azacytidine combination treatment notified with efficacy and a very
favorable toxicity profile in literature(10). Despite encouraging
results no benefit was obtained.