Flotufolastat F 18 shows high detection rate in patients with low PSA levels

A post-hoc analysis from the phase 3 SPOTLIGHT trial (NCT04186845) exploring flotufolastat F 18 (formerly 18F-rhPSMA-7.3; trade name, Posluma) injection showed a moderate to high detection rate of the agent in patients with suspected biochemical recurrence of prostate cancer and low to very low prostate specific antigen (PSA) levels.

Data from the post-hoc analysis showed that 68% of patients with a PSA level below 1 ng/mL had a positive flotufolastat F 18 scan.

The data were presented by Ashesh B. Jani, MD, MSEE, FASTRO, on behalf of the SPOTLIGHT study group at the 2023 American Society for Radiation Oncology (ASTRO) meeting in San Diego, California.^1,2

Data from the post-hoc analysis showed that 68% of patients with a PSA level below 1 ng/mL had a positive flotufolastat F 18 scan, as well as 76% of patients with a PSA level between 0.5 ng/mL or greater and less than 1 ng/mL, and 64% of patients with a PSA level of less than 0.5 ng/mL.

Further, 21% of patients with a PSA level less than 0.5 ng/mL had observed extrapelvic lesions, which rose to 39% of patients with a PSA level of 0.5 ng/mL or greater to 1 ng/mL.

“Recurrent prostate cancer presents clinical challenges, and the ability to determine the extent and location of recurrent disease is necessary to inform physicians and their patients for appropriate clinical management. The SPOTLIGHT study investigated the diagnostic performance of Posluma PET imaging as a potential decision-making aid in assessing suspected biochemical recurrence of the disease, and demonstrated precision diagnostic performance, with an overall 83% (322/389) detection rate,” commented Jani in a news release on the findings.² Jani is a professor of radiation oncology and the James C. Kennedy Professor in Prostate Cancer at the Winship Cancer Institute of Emory University in Atlanta, Georgia.

Jani continued, “This post-hoc analysis further examined POSLUMA performance in 188 men with low-very low PSA levels. Results showed that more than two-thirds of these men were found to have positive Posluma scans, with a quarter of them having extrapelvic lesions. Posluma PET may be a useful tool for treatment planning, particularly in patients with suspected early recurrence of disease who may be candidates for curative salvage therapy.”

The SPOTLIGHT trial explored the diagnostic performance of flotufolastat F 18 in patients with suspected prostate cancer recurrence. All participants underwent PET 50 to 70 minutes following injection of 296 MBq flotufolastat F 18. All scans were evaluated by majority read of 3 blinded central readers.

The post-hoc analysis included all patients with an evaluable flotufolastat F 18 PET and a baseline PSA less than 1 ng/mL, yielding a total of 188 patients. The primary outcome measure was the detection rate of flotufolastat F 18, defined as the percent of positive PET scans.

Overall, detection rates were shown to be moderate to high, with patient-level detection rate increasing as PSA level increased. Regional detection rates were broadly concordant across all PSA categories.

No serious adverse events related to flotufolastat F 18 were reported in the SPOTLIGHT study. Treatment-emergenst adverse events (TEAE) potentially related to or related to flotufolastat F 18 were reported in 16% of patients. The most common TEAEs were hypertension (1.8%), diarrhea (1.0%), injection site reaction (0.5%), and headache (0.5%).

References

1. Detection Rate of 18F-rhPSMA-7.3 PET in patients with suspected prostate cancer recurrence at PSA levels <1 ng/mL: Data from the Phase 3 SPOTLIGHT study. Presented at the American Society for Radiation Oncology (ASTRO) Annual Meeting. October 1-4, 2023. San Diego, California.

2. New data on POSLUMA (Flotufolastat F 18) in patients with suspected biochemical recurrence of prostate cancer and low-very low prostate specific antigen (PSA) levels presented at ASTRO. News release. Blue Earth Diagnostics. October 2, 2023. Accessed October 3, 2023. https://www.businesswire.com/news/home/20230929119301/en