After craniotomy and maximal resection, the ADP adenovirus was injected into remaining tumor tissue and/or the adjacent brain tissue around the resection cavity. Patients received prodrug therapy consisting of 4 days of 5-fluorocytosine (150 mg/kg/day, orally) and valganciclovir (1800 mg/daily) for 13 days. 6-7 days post-surgery, patients received 4 doses of fSRS (32Gy total). Toxicity, virus persistence, immunological cytokines, and immune cell activation were measured up to day 30. The study followed a 3+3 design, with 3 doses of viral particles (1x10¹¹, 3x10¹¹, 1x10¹²).

A total of 16 patients with rGBM, IDH1wt, were enrolled. One patient in cohort 1 had a seizure and another patient in cohort 3 had focal weakness, the trial was extended by 6 patients. The Ad5-yCD/mutTK_SR39rep-ADP adenovirus plus fSRS was safe and well tolerated in rGBM. MTD was not reached. The majority of adverse events were grade 1 or 2. Grade 3 adverse events included one event of headache, nausea, vomiting, hyponatremia, seizure, weakness and were not attributed to study treatment. No grade 4 or 5 events were observed.