Chugai Pharmaceutical announced that Japan’s Ministry of Health, Labour and Welfare (MHLW) has approved the FoundationOne CDx Cancer Genomic Profile as a companion diagnostic to identify patients with BRAF V600 alterations or BRAF fusion-positive glioma who may be eligible for treatment with tovorafenib.
The companion diagnostic approval was granted on June 17, 2026, and was announced by Chugai on September 16, following the Japanese regulatory approval of tovorafenib by Ipsen for low-grade glioma (LGG) harboring a BRAF gene mutation or fusion.
The expanded indication allows FoundationOne CDx to detect BRAF V600 alterations and BRAF fusion genes in glioma tissue to support treatment decisions involving tovorafenib. According to Chugai, the addition expands the test’s companion diagnostic capabilities to nine cancer types, alongside its existing applications across several molecularly defined malignancies.
Tovorafenib Approved for BRAF-Altered Low-Grade Glioma in Japan
On September 16, Ipsen announced that the MHLW had approved tovorafenib tablets 100 mg and tovorafenib dry syrup 300 mg for patients with low-grade glioma harboring BRAF gene mutations or fusion genes.
Tovorafenib is an oral type II RAF inhibitor developed to target alterations in the RAF/MAPK signaling pathway. The drug is administered once weekly and is active against BRAF V600 alterations as well as BRAF fusions and rearrangements. Ipsen noted that the approval makes tovorafenib the first molecularly targeted treatment available in Japan specifically for LGG with a BRAF fusion.
Low-grade gliomas are among the most common brain tumors in children. Although they generally grow relatively slowly, recurrent or progressive disease can require repeated treatment and may result in long-term neurological, visual, endocrine and cognitive complications. BRAF alterations are among the major molecular drivers identified in pediatric low-grade glioma.
FIREFLY-1 Trial Supported Tovorafenib Approval
The Japanese approval of tovorafenib was supported by results from the international, multicenter Phase 2 FIREFLY-1 trial (NCT04775485), which evaluated tovorafenib in patients with relapsed or refractory low-grade glioma harboring activating BRAF alterations.
In the latest analysis cited by Ipsen, the objective response rate by independent central review using RANO-HGG criteria was 71%. Using RAPNO-LGG criteria, the objective response rate was 53%, with a median duration of response of 19.7 months.
Reported treatment-related adverse events included hair color changes, increased blood creatine phosphokinase, growth deceleration, and anemia.
The FIREFLY-1 study enrolled children and young adults with relapsed or progressive pediatric low-grade glioma with activating BRAF alterations and evaluated once-weekly tovorafenib monotherapy. The study is registered as NCT04775485.
The Phase 2 FIREFLY-1 trial results were published in Nature Medicine (doi.org/10.1038/s41591-023-02668-y), reporting the efficacy and safety of tovorafenib
Expanding the Role of FoundationOne CDx
FoundationOne CDx is a next-generation sequencing-based comprehensive genomic profiling assay developed by Foundation Medicine. Using DNA extracted from formalin-fixed, paraffin-embedded tumor tissue, the test assesses substitutions, insertions and deletions, and copy-number alterations across 324 genes, as well as selected gene rearrangements.
The platform also evaluates genomic signatures including microsatellite instability (MSI) and tumor mutational burden (TMB). In Japan, the assay already serves as a companion diagnostic for multiple targeted therapies across cancers including non-small cell lung cancer, melanoma, breast cancer, colorectal cancer, ovarian cancer, prostate cancer and biliary tract cancer.
With the latest approval, FoundationOne CDx can now be used to identify BRAF V600 alterations and BRAF fusion genes in glioma, connecting comprehensive genomic profiling with the newly approved targeted treatment option tovorafenib.
The simultaneous expansion of molecular testing and targeted treatment availability represents another step toward biomarker-guided treatment of low-grade glioma in Japan.
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