18F-rhPSMA-7.3 PET image showing prostate cancer spread beyond the prostate region (Photo courtesy of Blue Earth Diagnostics)
November 2, 2022 — Blue Earth Diagnostics, a Bracco company and recognized leader in the development and commercialization of innovative PET radiopharmaceuticals, today announced results from its Phase 3 SPOTLIGHT trial that evaluated the impact of various clinical factors, including baseline Prostate Specific Antigen (PSA) levels, PSA doubling time and Gleason score, on detection rates (DRs) for 18F-rhPSMA-7.3 in recurrent prostate cancer. 18F-rhPSMA-7.3 is an investigational high affinity radiohybrid (rh) Prostate-Specific Membrane Antigen-targeted PET imagingagent. The results were reported in an oral presentation at the American Society for Radiation Oncology (ASTRO) 2022 Annual Meeting in San Antonio, Texas.
“The ability to determine the extent and location of recurrent prostate cancer to inform appropriate clinical management for these men is key for physicians and their patients, because up to 40% of patients who undergo radical prostatectomy, and up to 50% of patients who undergo radiation therapy will develop local or distant recurrences within 10 years,” said Benjamin Lowentritt, MD, Chesapeake Urology Research Associates, Towson, Md., on behalf of the SPOTLIGHT Study Group. “A rising PSA after radical prostatectomy usually precedes a clinically detectable recurrence by years, but cannot differentiate between local, regional, or systemic disease. The utility of conventional imaging for the localization of recurrence is limited, particularly in patients with low PSA levels. Relapse after curative-intent primary treatment remains a considerable clinical burden, and precise imaging techniques are required to identify areas of involvement to facilitate the delivery of optimized patient management. These findings from the SPOTLIGHT study showed high DRs by majority read for 18F-rhPSMA-7.3 PET over a wide range of baseline PSA levels.”
“These results from the Phase 3 SPOTLIGHT trial in biochemically recurrent prostate cancer are included in our New Drug Application for 18F-rhPSMA-7.3 PET imaging currently under review by the U.S. Food and Drug Administration, and we are pleased that they are being presented to the radiation oncology community at ASTRO 2022,” said David E. Gauden, D.Phil., Chief Executive Officer of Blue Earth Diagnostics. “In line with our mission to help patients with cancer across the care continuum, Blue Earth Diagnostics continues to develop our comprehensive prostate cancer portfolio, which includes 18F-fluciclovine and investigational rhPSMA compounds for potential use in diagnostic PET imaging and targeted radiopharmaceutical therapy. 18F-rhPSMA-7.3 represents a new class of PSMA-targeted PET radiopharmaceuticals, with early studies 18F‐rhPSMA‐7.3 showing a high binding affinity for PSMA, together with biodistribution data suggesting the potential for low bladder activity.”
The findings presented at ASTRO included analyses of clinical factors impacting DRs for 18F-rhPSMA-7.3 evaluated by three blinded central readers: DRs, including region-level analyses, stratified by baseline PSA levels, PSA doubling time, Gleason score and prior treatment (radical prostatectomy with or without radiotherapy, or radiotherapy only). For example, results showed that among the 389 patients in the Evaluable PET Scan Population, the patient-level DR of 18F-rhPSMA-7.3 PET by majority read was 83% (322/389). When stratified by PSA level, the DRs were: PSA <0.5 ng/mL: 64% (77/121); PSA ≥0.5 and <1 ng/mL: 76% (51/67); PSA ≥1 and <2 ng/mL: 93% (42/45); PSA ≥2 and <5 ng/mL: 98% (86/88); PSA ≥5 and <10 ng/mL: 94% (34/36); and PSA ≥10 ng/mL: 100% (32/32). As noted previously, no serious adverse reactions were attributed to 18F-rhPSMA-7.3 PET in the SPOTLIGHT study. Overall, 16 (4.1%) patients had at least one treatment-emergent adverse event that was considered possibly related/related to 18F-rhPSMA-7.3. The most frequently reported events were: hypertension: 1.8% (n=7); diarrhea: 1.0% (n=4); injection site reaction: 0.5% (n=2), and headache: 0.5% (n=2).
The SPOTLIGHT trial (NCT04186845) is a Phase 3, multi-center, single-arm imaging study conducted in the United States and Europe to evaluate the safety and diagnostic performance of 18F-rhPSMA-7.3 PET imaging in men with suspected prostate cancer recurrence based on elevated PSA following prior therapy. Key results for 18F-rhPSMA-7.3 PET were previously presented at ASCO GU in February 2022,1 with additional results announced at AUA in April 20222 and at SNMMI in June 2022.3
The findings were discussed in an oral presentation at ASTRO 2022 on October 24, 2022, “Impact of clinical factors on 18F-rhPSMA-7.3 detection rates in men with recurrent prostate cancer: Findings from the phase 3 SPOTLIGHT study,” by Benjamin Lowentritt, MD, Chesapeake Urology Research Associates, Towson, Md., on behalf of the SPOTLIGHT Study Group. Full session details and the abstract are available in the ASTRO online program HERE.
About Radiohybrid Prostate-Specific Membrane Antigen (rhPSMA)
rhPSMA compounds consist of a radiohybrid (“rh”) Prostate-Specific Membrane Antigen-targeted receptor ligand which attaches to and is internalized by prostate cancer cells and they may be radiolabeled with 18F for PET imaging, or with isotopes such as 177Lu or 225Ac for therapeutic use – creating a true theranostic technology. They may play an important role in patient management in the future, and offer the potential for precision medicine for men with prostate cancer. Radiohybrid technology and rhPSMA originated from the Technical University of Munich, Germany. Blue Earth Diagnostics acquired exclusive, worldwide rights to rhPSMA diagnostic imaging technology from Scintomics GmbH in 2018, and therapeutic rights in 2020, and has sublicensed the therapeutic application to its sister company Blue Earth Therapeutics. Blue Earth Diagnostics has completed two Phase 3 clinical studies evaluating the safety and diagnostic performance of 18F-rhPSMA-7.3 PET imaging in prostate cancer: (“SPOTLIGHT,” NCT04186845), in men with recurrent disease and (“LIGHTHOUSE,” NCT04186819), in men with newly diagnosed prostate cancer. Currently, rhPSMA compounds are investigational and have not received regulatory approval.
For more information: www.bluearthdiagnostics.com
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