A phase 1 GT-20 trial in 9 patients with newly diagnosed MGMT-unmethylated glioblastoma found the personalised DNA-based neoantigen vaccine GNOS-PV01 was well tolerated and generated strong T-cell responses in nearly all evaluated patients; 66.7% were progression-free at 6 months and alive at 12 months. Published in Nature Cancer, the single-arm study also reported median progression-free survival of 8.5 months, median overall survival of 16.3 months, and 1 survivor beyond 4 years.

Why It Matters To Your Practice

• MGMT-unmethylated glioblastoma carries a poor prognosis and limited effective options after standard surgery and radiation.

• This personalised vaccine approach suggests glioblastoma may be more immunologically targetable than prior vaccine efforts indicated.

• Advanced practice clinicians may increasingly help identify eligible patients early for referral to neuro-oncology centers running individualized immunotherapy trials.

Clinical Benefits

• GNOS-PV01 used 17 to 40 tumour-specific neoantigens tailored to each patient.

• No serious adverse events, unexpected toxicities, or dose-limiting toxicities were reported in the 9 treated patients.

• The vaccine activated and expanded circulating T cells in all evaluated patients except 1 receiving dexamethasone.

• Reported outcomes included 66.7% progression-free survival at 6 months, 66.7% overall survival at 12 months, 33% overall survival at 24 months, and 1 patient alive more than 4 years after surgery.

Managing Risks

• This was a small, open-label, single-arm phase 1 study, so efficacy signals should be interpreted cautiously.

• Corticosteroid exposure may blunt immune response; 1 patient on dexamethasone did not show the same T-cell activation.

• The vaccine was given after resection and radiation, so coordination with specialty teams remains essential.

• Access is currently limited to specialized centers and clinical trial settings.

The Bottom Line

• For newly diagnosed MGMT-unmethylated glioblastoma, GNOS-PV01 showed an encouraging early safety and immunogenicity signal.

• For NPs and PAs, the practical takeaway is to recognize potential trial candidates quickly, minimize unnecessary immunosuppression when feasible, and support referral discussions early in the treatment course.