Safety and effectiveness of18F-fluciclovine PET in adults with recurrent glioma: A retrospective observational study

496 Objectives: Gliomas are the most common primary brain tumor in the US.1 Currently, magnetic resonance imaging (MRI) is used to image gliomas, both for diagnosis and to monitor response to therapy. However, its utility is limited due to non-enhancing low-grade gliomas, and similar imaging findings with pseudo-progression and true recurrence on the initiation of a new treatment.2 The amino acid positron emission tomography (PET) tracer, 18F-fluciclovine, has Orphan Drug designation in the USA and Europe for the imaging of gliomas. Here, we report the safety and effectiveness of 18F-fluciclovine in the detection of recurrent gliomas using data from a retrospective observational study that analyzed results from multiple research sites. Methods: Data from two investigator-sponsored studies in the USA and a compassionate use program in Norway from adults who received 18F-fluciclovine PET for the detection of glioma were collected. The primary objective was to determine the positive predictive value (PPV) of 18F-fluciclovine PET to detect glioma in comparison to a histopathological truth standard. Secondary objectives included determination of the detection rate, sensitivity, specificity, and negative predictive value (NPV). A further objective was to evaluate adverse events (AEs) in any patient who received 18F-fluciclovine; any serious AE that occurred up to 35 days after injection of 18F-fluciclovine was reviewed.18F-Fluciclovine PET images that were evaluated by experienced readers prior to data collection, with lesions classified as either ‘positive’ or ‘negative’ for malignancy on the basis of visual assessment against an appropriate background were eligible for inclusion. Lesions with indeterminate results were excluded from analyses. A further requirement for the 18F-fluciclovine PET to have been conducted within 30 days of the histological truth standard being collected was set. Results: Between August 2004 and May 2015, data were collected from 82 patients. Of these, 18 scans met the diagnostic analysis criteria, 17 of which were from patients with recurrent glioma. These 17 patients, 71% of whom were male, 71% of whom had high grade tumors, and who had a median age of 55.0 years form the effectiveness cohort for the current analysis.Among the 17 patients with recurrent glioma, 18F-fluciclovine PET showed a PPV of 88.2%, a detection rate of 100% and sensitivity of 100%. In patients with recurrent high-grade glioma (n = 12), the PPV, detection rate and sensitivity were 83.3%, 100% and 100%, respectively, while in patients with recurrent low-grade glioma (n = 5) these were 100%, 100% and 100%, respectively. The specificity and NPV could not be calculated as no patients had a negative 18F-fluciclovine PET scan.In total, 3/82 (3.7%) patients experienced at least one treatment-emergent AE during the safety monitoring period. There was one fatal event of worsening glioblastoma which was considered unrelated to 18F-fluciclovine. All other treatment-emergent AE were considered TCAE Grade 1 in severity and were unrelated to 18F-fluciclovine. Conclusions: 18F-Fluciclovine PET is well tolerated and able to effectively detect the presence of tumors in adults with recurrent gliomas.