NIMG-71. REAL-WORLD ASSESSMENT OF IDH1 INHIBITOR IVOSIDENIB IN IDH MUTANT LOWER GRADE GLIOMAS – THE JOHNS HOPKINS EXPERIENCE. (14th November 2022)

• Record Type: Journal Article
• Authors: Puri, Sushant; Shi, Jessica; Blair, Lindsay; Blakeley, Jaishri; Laterra, John; Kamson, David
• Is Part Of: Neuro-oncology. Volume 24(2022)Supplement 7
• Page Start: vii181
• Page End: vii181
• Publication Date: 2022-11-14
• Subjects: Brain Neoplasms -- Periodicals; Brain -- Tumors -- Periodicals; Brain -- Cancer -- Periodicals; Nervous system -- Cancer -- Periodicals; 616.99481
• DOI: 10.1093/neuonc/noac209.689
• Languages: English
• ISSNs: 1522-8517

Abstract

Abstract: BACKGROUND: As clinical trials are ongoing to establish the role of IDH inhibitors in the treatment of lower-grade gliomas, long-term data is not yet available. Hence, here we share our real-world experience with off-label ivosidenib. METHODS: In this single-institution retrospective analysis, we included chemo/radiotherapy-naïve, gadolinium non-enhancing WHO Grade 2/3 IDH1-mutated astrocytomas (AS) and oligodendrogliomas (OG) that were treated with off-label ivosidenib for ≥ 5 months for active tumor growth. We performed semi-automated volumetric analyses on T2/FLAIR images in 3D Slicer v4.11. Annualized growth-rates before and on ivosidenib were calculated, and time to initial response (reduction in growth-rate), growth arrest (growth-rate ≤ 0cc/yr) and shrinkage in patients with confirmatory data available (≥ 1 confirmatory follow-up scan). Progression-free survival (PFS), at 6 and 12 months were assessed (progression defined as ≥ 40% volume increase per RANO 3D). RESULTS: We studied 12 patients (2F, median age 46yrs [range 26-60], 8/4 AS/OG; 4 grade 3) with an average of 17.2 months (5-33) follow-up on ivosidenib. Eleven (92%) patients had confirmatory data. Response rate was 82% (9/11) with median time of 4.9 (3.5-6.3) months to initial response and 11.1 (4.1-21.4) months to growth arrest. Growth arrest occurred 3-folds faster in OG than in AS (4.2±0.8 vs.12.5±4.2 months, p=0.014). Mean best response was 11.4±12.8% volume reduction, after a median of 12.1±9.3 months on ivosidenib. Mean PFS was 24.4 months (CI95%18.8-29.9). PFS-6 and PFS-12 were 91%, and 88% (7/8), respectively. No major toxicity was noted. There were 3 discontinuations, two for radiographic progression, one for increased seizure frequency. CONCLUSIONS: In this small cohort, ivosidenib was well-tolerated with a high response rate; however, responses took up to a year to become evident and seemingly faster in oligodendrogliomas. These data suggest that ivosidenib might require more than 5 months of commitment and volumetrics may help the detection of early response.