Abstract
Background
Pediatric low-grade gliomas (pLGG) are the most common pediatric central nervous system tumors, with driving alterations typically occurring in the MAPK pathway. The ERK1/2 inhibitor ulixertinib (BVD-523) has shown promising responses in adult patients with mitogen-activated protein kinase (MAPK)-driven solid tumors.
Methods
We investigated the anti-tumoral activity of ulixertinib monotherapy as well as in combination with MEK inhibitors (MEKi), BH3-mimetics, or chemotherapy in pLGG. Patient-derived pLGG models reflecting the two most common alterations in the disease,
KIAA1549:
BRAF-fusion and BRAF
V600E mutation (DKFZ-BT66 and BT40, respectively) were used for
in vitro and
in vivo (zebrafish embryos and mice) efficacy testing.
Results
Ulix ertinib inhibited MAPK pathway activity in both models, and reduced cell viability in BT40 with clinically achievable concentrations in the low nanomolar range. Combination treatment of ulixertinib with MEKi or BH3-mimetics showed strong evidence of anti-proliferative synergy
in vitro. Ulixertinib showed on-target activity in all tested combinations.
In vivo, sufficient penetrance of the drug into brain tumor tissue in concentrations above the
in vitro IC
50 and reduction of MAPK pathway activity was achieved. In a preclinical mouse trial, ulixertinib mono- and combined therapies slowed tumor growth and increased survival.
Conclusions
These data indicate a high clinical potential of ulixertinib for the treatment of pLGG and strongly support its first clinical evaluation in pLGG as single agent and in combination therapy in a currently planned int ernational phase I/II umbrella trial.
