Jonathan Allis, D. Phil Biochemistry, CEO of Blue Earth Diagnostics Ltd. in Burlington, MA presented the data at the 2016 Society of Nuclear Medicine and Molecular Imaging Conference.
Dr. Allis reported one-third of men treated for primary prostate cancer will have a biochemical based recurrence in 10 years and of those an additional one-third will progress to metastatic disease. However, only 11% of these recurrences are detected by standard CT imaging.
In an effort to increase disease detection FACBC was developed, originally by Emory University, as a amino acid which is transported by the LAT-1 and ASCT2 amino acid transporters, which are up regulated in in many cancer cells, including prostate cancer. Once within the cell, the synthetic amino acid is not metabolized, which provides accumulation of the F18 radiotracer within the cancer cell and resultant high signal to noise. In addition FACBC has been shown to have uptake in both prostate-specific membrane antigen (PSMA) expressing and non-expressing cell lines, suggesting possible increased sensitivity compared to other PSMA PET agents.
Unlike many current PET agents only 3% of the radiotracer is excreted into the urine, which provides clearer signal for review of the prostate bed. This can be further improved by the FACBC uptake time of 4-10 minutes, which based on the physiologic distribution provides maximal tumor and lymph node uptake with minimal bladder activity.
The safety and efficacy of FACBC were evaluated in two studies, Study 1 and Study 2. Study 1 examined 105 F18-FACBC PET/CT scans and compared the images against histopathologic data, with the images being read by an on-site reader and then subsequently by three blinded independent readers. The results of the three blinded readers were generally consistent and similar to those of the on-site interpretations. Dr. Allis reported patients with PSA of <1.78 had a detection rate of 60% of which 73% were confirmed on histology. In patients with a PSA of >1.78 there was an 80% true detection rate. Of note, the three readers reported a <10% extraprostatic false positive rate.
Study 2 looked at 96 patients and compared FACBC to C11-choline. The on-site reader read the C11-choline studies ,while the FACBC scans were reviewed by the three independent readers used for Study 1. The agreement values between FACBC and C11-choline interpretations were reported to range from 61% - 77%.
Blue Earth Diagnostics has partnered with PETNET Solutions to be the exclusive provider of FACBC with a goal of having 11 PETNET sites providing the radiotracer by the end of 2016.
Why is this important? The FACBC radiotracer may provide significant improvement in early detection of disease recurrence, which will hopefully result in improved patient outcomes. It also is also one of the few molecular imaging agents, which allows for examination of both soft tissue and osseous metastatic disease in a single study.
Presented by Jonathan Allis, D. Phil Biochemistry, CEO Blue Earth Diagnostics Ltd. at the 2016 Society of Nuclear Medicine and Molecular Imaging Conference – June 11-15, 2016 – San Diego Conference Center – San Diego, California USA
Written By: Rustain Morgan, MD, MS, Duke University Hospital Nuclear Radiology Fellow.