Dr Kline on Updated Efficacy Data With Tovorafenib in R/R Pediatric Low Grade Glioma

"The time to next treatment being over 40 months for our patient population, ideally, is giving our patients and families this nice long period of not necessarily needing additional therapies."

Cassie Kline, MD, MAS, an attending physician and director of clinical research in the Department of Neuro-Oncology at the Children's Hospital of Philadelphia, shared updated results from the ongoing phase 2 FIREFLY-1 study (NCT04775485) evaluating tovorafenib (Ojemda) in relapsed/refractory pediatric low-grade glioma (pLGG).

Prior results from FIREFLY-1 supported the FDA approval of tovorafenib for recurrent BRAF-altered pLGG in April 2024. The updated data, encompassing approximately 36 months of follow-up, were presented at the 2025 SNO Annual Meeting.

The results demonstrated that tovorafenib induced durable responses in patients with recurrent BRAF-altered pLGG. Updated data showed that evaluable patients (n = 76) achieved an overall response rate (ORR) of 53%, including a partial response rate of 39% and a minor response rate of 13%. The median duration of response was 19.4 months (95% CI, 13.8-27.2), and the median time to response was 5.4 months (95% CI, 1.6-17.5). Kline highlighted that the updated data identified a very long period of time to next treatment, which was 42.6 months (95% CI, 36.7-not evaluable).

However, the study also confirmed favorable treatment completion and treatment-free intervals, she said. The majority of patients (58%) were able to finish at least 26 cycles of therapy, and most who stopped treatment after completing 26 cycles were able to remain treatment-free for up to a year. This long interval could offer patients and families a significant period without needing additional therapies, Kline noted.

These findings are promising regarding the agent's potential clinical benefit, tolerability, and ongoing disease control once patients cease treatment, Kline stated. Furthermore, the updated follow-up identified no new safety signals, she added. The cohort now includes a small number of patients who have entered a retreatment arm after coming off the drug and experiencing tumor changes that warranted a second course of therapy. Kline expressed excitement over seeing the response data from the 3-year follow-up and the retreatment cohort.