INDIGO: A GLOBAL, RANDOMIZED, DOUBLE-BLINDED, PHASE 3 STUDY OF VORASIDENIB VERSUS PLACEBO IN PATIENTS WITH RESIDUAL OR RECURRENT GRADE 2 GLIOMA WITH AN IDH1/2 MUTATION Free

Current treatments grade 2 gliomas are not curative and can be associated with short- and long-term toxicities. Vorasidenib (VOR), an oral, brain-penetrant, dual inhibitor of mutant (m)IDH1/2 enzymes, has shown a tolerable safety profile and preliminary clinical activity in phase 1 studies.

In the phase 3 INDIGO study (NCT04164901), patients (pts) were randomized 1:1 to receive VOR 40 mg daily or placebo (PBO) daily in 28-day cycles. Patients were stratified by 1p19q status and baseline tumor size. Key eligibility criteria included: age ≥12; KPS >80; residual or recurrent grade 2 IDH1m or IDH2m oligodendroglioma or astrocytoma; measurable non-enhancing disease; no prior treatment for glioma with most recent surgery 1-5 years from randomization; and not in immediate need of chemotherapy/radiation. Primary endpoint: radiographic progression-free survival (PFS) by blinded independent radiology committee (BIRC). Key secondary endpoint: time to next intervention (TTNI).

As of 06 Sep2022, 331 pts were randomized across 10 countries: 168 to VOR and 163 to PBO. Median PFS by BIRC was 27.7 mos with VOR and 11.1 with PBO (HR, 0.39; 95% CI, 0.27, 0.56; 1-sided P=0.000000067). Median TTNI was not reached with VOR and 17.8 mos with PBO (HR, 0.26; 95% CI, 0.15, 0.43; 1-sided P=0.000000019). All-grade adverse events (AEs) occurring in >20% pts receiving VOR vs PBO were alanine aminotransferase increased, COVID-19, fatigue, aspartate aminotransferase increase, headache, diarrhea, nausea. Common grade ≥3 AEs (>5%): ALT increased (9.6% vs 0%).

VOR significantly improved PFS by BIRC versus PBO with a manageable safety profile.

© 2023 American Society of Clinical Oncology, Inc. Reused with permission. This abstract was accepted and previously presented at the 2023 ASCO Annual Meeting. All rights reserved.