Efficacy of a novel potent and high water-soluble selective PARP inhibitor CVL218 in glioma.

Abstract

e13539 Background: Glioma is the most common, deadly, and difficult-to-treat intracranial tumor. Up to 70% of gliomas are found to carry isocitrate dehydrogenase (IDH) mutations, which induce a homologous recombination defect (HRD) that renders glioma cells sensitive to poly (ADP-ribose) polymerase inhibitors (PARPi). However, 4 launched PARPi have limitation for IDH-mutant glioma because of low concentration level in brain. CVL218 is a novel potent and high water-soluble selective PARP-1/2 inhibitor. Pharmacokinetic studies in rats showed that CVL218 can easily across the BBB, has 10 times higher concentration in brain than in the plasma, indicating its therapeutic potential in glioma. Here, we examined its effect on glioma in vitro and in vivo. Methods: BT142 mut/- glioma cells with a homozygous IDH1 R132H mutation were exploited. Chemotherapeutic agent temozolomide (TMZ), PARPi Olaparib and Niraparib, were used as controls. The inhibition of BT142 cell growth by compounds in vitro was measured by MTT assay. Female NOD/SCID mice with orthotopic xenografts of BT142 glioma cells were used to evaluate the antitumor efficacy of compounds in vivo. Medium survival time (MST) was compared using the Kaplan-Meier method and logrank test. Results: CVL218 inhibited the BT142 cell growth in vitro with an IC50 of 2.07 ± 0.62 μM, better than Olaparib and Niraparib. Orthotopic xenograft glioma mice model study showed that CVL218 group significantly extended the MST to 98.0 days ( p= 0.0206), while MST of TMZ treated group is 85.0 days. Conclusions: CVL218 inhibits IDH1-mutant BT142 glioma cell growth in vitro and in vivo. The present findings suggest that CVL218 is a potential agent which could be useful as a treatment for IDH-mutant glioma. We will start its phase I clinical study for glioma soon.