gms | German Medical Science

Objective: The best treatment options for recurrent Glioblastoma multiforme (GBM) are matter of debate and new treatment concepts are desperately needed. Interstitial photodynamic therapy (iPDT) appears to be a promising approach in the multimodal treatment of recurrent GBM. At the moment it is used in a compassionate use setting only. However, the results are quite promising. We will initiate a randomized, controlled, prospective, multicenter, non blinded trial which is expected to start in 2018 to prove the effectiveness of 5 ALA PDT in recurrent GBM. I PDT is a treatment concept combining local and potential immunological effects. The study will include a translational investigation as well as a clinical investigation.

Methods: The primary end point will be the progression free survival of the recurrent GBM suffering patient, treated with iPDT. Secondary efficacy endpoints will be survival and progression as well as the response rate on MRI. Clinical outcome will be measured by change in KPS, NIHSS and MMSE. Quality of life will be measured with the EORTC QLQ-C30 score and the score assessed by means of the QLQ-BN20 module. Additionally the eligibility of diffuser laser probes for iPDT in brain applications will be investigated. Patients will be randomized 1:1. The treatment arm receives 5-ALA HCl orally (20 mg/kg bw), 3.5 – 4.5 hours prior to induction of anesthesia: Under anesthesia stereotactic biopsy to verify glioblastoma followed by iPDT in case of positive frozen section result will be performed. The control arm will receive biopsy only. All patients will receive further treatment of recurrent glioblastoma at the investigator's discretion. The trail will be event controlled, including an interim analyses after 37 events. A total number of 106 patients will be expected for the complete trail.

Results: The study is funded by the Deutsche Krebshilfe and is approved by the ethics committee. The fibers will be investigated as medical product. Approval by the "Bundesamt für Medizinprodukte" has been granted. The Laser will be part of the protocol but will not be investigated separately.

Conclusion: With this trial we expect to generate an approved treatment modality as possible standard treatment for the recurrent situation in an adequate patient collective.