Health Canada has approved vorasidenib, marketed as Voranigo, as the first targeted therapy for treating Grade 2 isocitrate dehydrogenase (IDH)-mutant glioma in adults and pediatric patients aged 12 and older, following surgery. This marks a significant advancement in the treatment of this brain cancer, offering a new oral treatment option that directly targets the mutated enzymes driving tumor growth.
Clinical Trial Results Demonstrate Significant Delay in Tumor Progression
Vorasidenib's approval is based on the results of a large-scale, randomized, placebo-controlled Phase 3 clinical trial involving patients worldwide. The study, published in the New England Journal of Medicine, demonstrated that vorasidenib significantly slowed tumor growth. Specifically, the median progression-free survival for patients on placebo was 11.1 months, while those receiving vorasidenib experienced a more than doubled progression-free survival of 27.7 months.
Dr. Mary Jane Lim-Fat, a neurologist and neuro-oncologist at Sunnybrook Health Sciences Centre, explained, "This new drug essentially is a brain penetrant oral drug that patients can take by mouth that alters the function of that mutant protein. So in doing that, it slows down the growth of the tumour, stabilizes it in some instances, and even decreases the growth or shrinks the tumours in some cases."
Addressing the Challenges of Treating Gliomas
Gliomas are particularly challenging to treat due to the blood-brain barrier, which limits the penetration of many therapies. Current treatments typically involve surgery followed by radiation and chemotherapy, which can temporarily halt tumor growth but often result in recurrence. Vorasidenib is designed to cross the blood-brain barrier and target the mutated IDH enzymes directly, offering a more targeted approach.
The approval of vorasidenib also means delaying the need for interventions like chemotherapy and radiation, which come with severe side effects.
Patient Impact and Future Outlook
Steven Stefanidis, a Toronto firefighter diagnosed with Grade 2 IDH-mutant glioma, participated in the clinical trials and has experienced positive results. "Since receiving the treatment during the clinical trials… there’s no side effects from the medication, and on the positive side, we’ve noticed stabilization and some shrinkage in the remaining [tumor]," he said. Stefanidis has returned to work and resumed his regular activities.
While the approval of vorasidenib represents a major breakthrough, some questions remain regarding long-term survival outcomes and potential differences in patient response. Dr. Lim-Fat noted, "We haven’t had a breakthrough like this in terms of a new drug in about 20 years… but nonetheless, we think it is a major breakthrough and major advancement in terms of providing more options for patients."
