516P - Building a new prognostic score for patients with central nervous system (CNS) tumors enrolled in early phase clinical trials

Background

Patients (pts) with primary CNS tumors are often excluded from early phase clinical trials because of doubts regarding the blood brain penetration, adherence to study treatment and use of corticosteroids in immunotherapy clinical trials. Scores built to help selectection of pts that would be good candidates for early phase clinical trials such as the Royal Marsden Score (RMH) or the Gustave Roussy Immune Score (GRIm) are not relevant to pts with primary CNS. We aimed to determine factors associated with prognosis to help physicians referring pts.

Methods

We conducted a retrospective analysis of all pts treated for a CNS tumor and enrolled in an early phase clinical trials at the Drug Development Department at Gustave Roussy between January 2013 and December 2022. Descriptive statistics were used to present the population and a multivariate Cox regression was used to determine prognostic factors in uni and multivariate analysis on overall survival (OS).

Results

A total of 108 pts were included in the study. Median age was 47 (18-82), most males (F/M=35/73), 44% were symptomatic in the three months before study entry, 46% had a multifocal disease at C1D1. The ratio between low grade glioma (LGG) and high grade glioma (HGG) according to the new molecular classification of 2021 were 24/84. Molecular alterations were: IDH mutation (59%), MGMT methylation (14.2%, 94 unknown), 1p19q codeletion (19.7%, 53 unkown). Targeted therapies were the most common drug used (44%), followed by immunotherapy (33.%) and epigenetic drugs (8.4%). Pts harbouring a BRAF mutation treated with a specific target therapy were 12; pts with an FGFR mutation or fusion treated in the same setting were 18. Median progression free survival (PFS) was 9.7 months, 40% of pts were progressing at 3 months. Altogether, 34% of pts were alive at 6 months. In multivariate analysis, lymphocyte counts ≥900/mm3 (HR=0.7 95% CI 0.46 - 1.07), absence of steroids at baseline (HR=2.3 95% CI 1.5 - 3.5), absence of antiepileptic drugs at baseline (HR=2.06 95%CI 1.2 - 3.7) were associated with a better overall survival.

Conclusions

Corticosteroid use, lymphocyte count and use of antiepileptics will be used to build a new score that will be presented at the conference.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.