Pazopanib efficacy in recurrent central nervous system hemangiopericytomas.
INTRODUCTION
There is currently no treatment for solitary fibrous tumors/hemangiopericytomas (SFT/H) of the central nervous system recurring after multiple surgeries and radiotherapies. The NAB2-STAT6 gene fusion is the hallmark of these tumors, and upregulates Early Growth Factor, activating several growth pathways.


METHODS
We treated two patients presenting pluri-recurrent meningeal SFT/H with Pazopanib, a broad-spectrum tyrosine kinase inhibitor. We analyzed the exome and RNA sequencing data of one of them and, in addition to another meningeal SFT/H, compared it to the transcriptomic profiling of 5 systemic SFT/H.


RESULTS
A dramatic clinical and radiological response was observed in both cases, respectively 84 and 43% decrease after 3 months. As a comparison, Pazopanib has only a stabilizing effect in systemic SFT/H. Indeed, central nervous system SFT/H show overexpression of different tyrosine kinases targeted by Pazopanib.


CONCLUSIONS
Two consecutive patients with untreatable central nervous system SFT/H showed a spectacular partial response to Pazopanib, an unprecedented result in SFT/H. This result could be explained by differences in expression profiles and calls for a confirmation in a larger cohort of patients.
['Apra|Caroline|C|http://orcid.org/0000-0003-0944-9544', 'Alentorn|Agusti|A|', 'Mokhtari|Karima|K|', 'Kalamarides|Michel|M|', 'Sanson|Marc|M|']
D000328:Adult D020533:Angiogenesis Inhibitors D016543:Central Nervous System Neoplasms D005260:Female D006393:Hemangiopericytoma D006801:Humans D007191:Indazoles D008297:Male D008875:Middle Aged D009364:Neoplasm Recurrence, Local D011743:Pyrimidines D054364:Solitary Fibrous Tumors D013449:Sulfonamides D016896:Treatment Outcome
Pazopanib Hemangiopericytoma Solitary fibrous tumor Fusion gene NAB2 STA6