Tovorafenib (DAY101)

Tovorafenib is an oral, once-weekly type II RAF inhibitor. In the United States, it received accelerated approval on 23 April 2024 for patients 6 months of age and older with relapsed or refractory pLGG harboring a BRAF fusion or rearrangement or BRAF V600 mutation, based on response rate and duration of response, and it remained on the FDA list of ongoing accelerated approvals in September 2026. In the European Union, a conditional marketing authorisation was granted on 20 April 2026 for the same molecular population after progression on one or more prior systemic therapies. In Japan, approval was obtained on 16 September 2026 for low-grade glioma with a BRAF gene mutation or fusion gene; the indication wording does not specify a line of therapy, although the supporting data came from FIREFLY-1. No marketing authorisation was identified in the United Kingdom, Canada, or Australia, and no supplemental application or EU variation for first-line use was identified. FIREFLY-2 is both the FDA confirmatory trial (final report due April 2032) and the EU specific obligation. First-line use in the United States and European Union is therefore outside the approved indications, and payer policy identified in the United States is limited to relapsed or refractory disease.

What is known for first-line use is limited to indirect and mechanistic evidence. Tovorafenib inhibits RAF monomers and dimers and is active in both BRAF fusion and BRAF V600E tumors, whereas type I BRAF inhibitors are not indicated for BRAF fusion tumors, and no targeted therapy is approved as first-line treatment for BRAF fusion-driven pLGG. The EMA considered that the mechanism of action is not expected to be line-dependent, and the company argues that earlier treatment may improve efficacy; in FIREFLY-1, median DOR was 24.0 months in MAPK inhibitor-naive versus 16.6 months in previously treated participants. What is not known is whether tovorafenib improves response, PFS, visual or functional outcomes, or quality of life compared with first-line chemotherapy; its efficacy and safety at the 420 mg/m2 dose used in FIREFLY-2 relative to the approved 380 mg/m2; the optimal treatment duration and the risk of rebound growth after stopping (31% of participants entering observation in FIREFLY-1); and its long-term effects on growth, adult height, fertility, and late toxicity in treatment-naive children, for which the EU risk management plan lists long-term safety as missing information.

The comparative position is defined by benchmarks from different trials rather than by direct comparison. First-line chemotherapy produced a 5-year EFS of 39% with carboplatin and vincristine in COG A9952 and a 5-year PFS of 46% with vincristine and carboplatin in SIOP-LGG 2004. In the randomized first-line trial of dabrafenib plus trametinib in BRAF V600 pLGG (110 participants), ORR was 47% versus 11%, median PFS was 20.1 versus 7.4 months (HR 0.31), and grade 3 or higher adverse events occurred in 47% versus 94% with carboplatin plus vincristine; the FDA approved this combination for first-line use in BRAF V600E pLGG on 16 March 2023. FIREFLY-2 does not include dabrafenib plus trametinib as a comparator. The EU Joint Clinical Assessment compared tovorafenib with dabrafenib plus trametinib only in relapsed or refractory BRAF V600E disease, using an unanchored MAIC against a dabrafenib plus trametinib study that included small proportions of patients with high-grade glioma or without prior systemic therapy: IRC-assessed PFS by RANO-LGG had a hazard ratio of 4.88 (95% CI 2.14 to 11.14), where values below 1 favor tovorafenib; ORR comparisons were inconclusive; and the odds ratio for grade 3 or higher adverse events was 12.65 (95% CI 2.30 to 69.58). The effective sample sizes were 5.81 to 14.26, prognostic factors including histology, tumor location, and prior chemotherapy were not adjusted for, and the assessors stated that the estimates "should not necessarily be interpreted as causal"; an independent commentary concluded that the limitations prevent a conclusion that tovorafenib is inferior. The safety profiles also differ: reductions in growth velocity have been observed only with tovorafenib, whereas no ocular toxicity, cardiac dysfunction, or abnormal weight gain was observed in FIREFLY-1, and tovorafenib is dosed once weekly with a liquid formulation available and without a food effect.

Guideline positions on first-line targeted therapy vary. European standard clinical practice recommendations (version dated 2022) state that first-line targeted therapy is acceptable only within clinical trials, with possible discussion for BRAF V600E tumors. A 2024 Canadian consensus suggests upfront BRAF inhibitor with or without MEK inhibitor for most BRAF V600E gliomas for 36 months, while retaining chemotherapy as an option. A 2026 Brazilian consensus recommends considering tovorafenib for KIAA1549-BRAF fusion LGG (85% agreement) without specifying a line of therapy and recommends against type I BRAF inhibitors in that population. The 2025 NCCN pediatric CNS guideline abstract describes a scope limited to diffuse high-grade gliomas and medulloblastomas, and no NCCN recommendation for tovorafenib in pLGG was confirmed.

Key uncertainties include the following source disagreements. The FIREFLY-2 primary endpoint is described as ORR per RANO-LGG in the 2024 design publication and as ORR per RAPNO-LGG in the registry record, the 2026 sponsor announcement, and the EMA assessment, which states that the change was made after 113 of 400 participants were recruited and that consistency of the treatment effect before and after the change will be of interest. FIREFLY-1 response rates vary with the criteria and assessor (67% by IRC-assessed RANO-HGG versus 51.3% by RAPNO-LGG at June 2023, and 71.0% by IRC versus 49.3% by investigators with RANO-HGG at May 2024). For the competing first-line MEK inhibitor strategy, a 2026 review states that the selumetinib phase 3 trials (NCT03871257 and NCT04166409) closed early because of poor accrual, whereas the registry records list NCT03871257 as active, not recruiting and NCT04166409 as recruiting. Company estimates of the RAF- or BRAF-altered fraction of pLGG also differ (50% to 60% RAF-altered versus approximately 70% BRAF-altered). Comparative first-line evidence is expected from FIREFLY-2, with topline data expected by mid-2027.