Long term follow-up of patients with newly diagnosed glioblastoma treated by intraoperative photodynamic therapy: an update from the INDYGO trial (NCT03048240)

Purpose Glioblastoma remains incurable despite optimal multimodal management. The interim analysis of open label, single arm INDYGO pilot trial showed actuarial 12-months progression-free survival (PFS) of 60% (median 17.1 months), actuarial 12-months overall survival (OS) of 80% (median 23.1 months). We report updated, exploratory analyses of OS, PFS, and health-related quality of life (HRQOL) for patients receiving intraoperative photodynamic therapy (PDT) with 5-aminolevulinic acid hydrochloride (5-ALA HCl). Methods Ten patients were included (May 2017 – April 2021) for standardized therapeutic approach including 5-ALA HCl fluorescence-guided surgery (FGS), followed by intraoperative PDT with a single 200 J/cm 2 dose of light. Postoperatively, patients received adjuvant therapy (Stupp protocol) then followed every 3 months (clinical and cerebral MRI) and until disease progression and/or death. Procedure safety and toxicity occurring during the first four weeks after PDT were assessed. Data concerning relapse, HRQOL and survival were prospectively collected and analyzed. Results At the cut-off date (i.e., November 1st 2023), median follow-up was 23 months (9,7–71,4). No unacceptable or unexpected toxicities and no treatment-related deaths occurred during the study. Kaplan–Meier estimated 23.4 months median OS, actuarial 12-month PFS rate 60%, actuarial 12-month, 24-month, and 5-year OS rates 80%, 50% and 40%, respectively. Four patients were still alive (1 patient free of recurrence). Conclusion At 5 years-follow-up, intraoperative PDT with surgical maximal excision as initial therapy and standard adjuvant treatment suggests an increase of time to recurrence and overall survival in a high proportion of patients. Quality of life was maintained without any severe side effects. Trial registration NCT number NCT03048240. EudraCT number: 2016–002706-39.