Phase 2/3 EMPIRE-1 Trial First to Show Increased Failure-Free Survival in Recurring Prostate Cancer

The phase 2/3 Emory Molecular Prostate Imaging for Radiotherapy Enhancement trial, or EMPIRE-1 trial (NCT01666808), is the first randomized trial of men with recurring prostate cancer to show that treatment based on advanced molecular imaging can improve disease-free survival rates.¹

The study, presented at the American Society for Radiation Oncology (ASTRO) Annual Meeting, used a type of PET known as fluciclovine (fluorine-18 or 18F; Axumin) which was invented by a multidisciplinary team at the Winship Cancer Institute of Emory University.²

"We knew that diagnostic performance of this PET radiotracer was better than conventional imaging. We also knew it changes management,” David M. Schuster, MD, FACR, nuclear radiology specialist at Winship Cancer Institute, said in a press release. “But did it change management in the right direction? This study has allowed us to take it one step further and determine if using this imaging influences outcomes for the better. And it does.”

From 2012 to 2019, 165 patients with prostate cancer with detectable post-prostatectomy and negative conventional imaging were stratified by prostate-specific antigen (PSA), adverse pathology, and androgen deprivation therapy (ADT) use. One group was randomized to receive radiation therapy based on conventional imaging (n = 82) and the other group received treatment that was finalized based on imaging with the fluciclovine PET radiotracer (n = 83).

Of note, 1 patient in the radiation therapy arm withdrew before receiving radiation therapy. In the PET arm, 3 patients withdrew before and 1 patient was unable to undergo PET, however this patient received radiation therapy.

Overall, those whose treatment was adjusted according to the results of the advanced molecular imaging showed an improvement in the cancer control end point. Moreover, toxicity was found to be similar in both treatment arms, suggesting PET-guided treatment was well-tolerated.

"At 3 years, the group getting treatment guided by PET fluciclovine had a 12% better cancer control rate, and this persisted at 4 years as well, with a 24% improvement," Ashesh B. Jani, MD, MSEE, FASTRO, Winship radiation oncologist and prostate cancer specialist, said in the release. "We think the improvement was seen because the novel PET allowed for better selection of patients for radiation, better treatment decisions, and better radiation target design."

However, the investigators also indicated that the integration of novel PET radiotracers into radiation therapy decisions and planning, including dose-escalation to regions of PET uptake, for patients with prostate cancer warrants further study.

Of note, the FDA approved the use of fluciclovine in 2016 to diagnose men with recurrent prostate cancer with elevated blood levels of prostate-specific antigen after previous treatment. It is the first FDA-approved fluorinated PET radiotracer for prostate cancer staging.

References:

1. Jani A, Schreibmann E, Goyal S, et al. Initial Report of a Randomized Trial Comparing Conventional- vs Conventional plus Fluciclovine (18F) PET/CT Imaging-Guided Post-Prostatectomy Radiotherapy for Prostate Cancer. Presented at the American Society for Radiation Oncology (ASTRO) Annual Meeting. Abstract #: LBA 1.

2. Winship study shows increased failure-free survival in prostate cancer [news release]. Published October 23, 2020. Accessed November 23, 2020. https://winshipcancer.emory.edu/about-us/newsroom/press-releases/2020/winship-study-shows-increased-failure-free-survival-in-prostate-cancer.html#.X7vNLRNKhH2