KEY TAKEAWAYS
- The Phase 3 SPOTLIGHT study analyzed 18F-rhPSMA-7.3 detection rates in patients with prostate cancer recurrence following primary treatment with radiation therapy.
- The study reported high 18F-rhPSMA-7.3 detection rates in patients with recurring prostate cancer post-radiation therapy.
A newly developed PET radiopharmaceutical, 18F-rhPSMA-7.3, specifically targets the prostate-specific membrane antigen and offers the advantage of minimal bladder activity. The SPOTLIGHT study investigated its performance in men experiencing prostate cancer recurrence. This report focused on the detection rates of 18F-rhPSMA-7.3 among a subset of SPOTLIGHT participants who had only undergone radiation therapy as their primary treatment.
Participants experiencing prostate cancer recurrence received a PET scan 50–70 minutes after intravenous injection of 296 MBq of 18F-rhPSMA-7.3. The scans were assessed by three independent central readers. Data were reported for both individual readers and instances where a majority of the readers (at least 2) concurred. Detection rates were further broken down based on the type of prior treatment received.
A total of 389 men received an evaluable scan using 18F-rhPSMA-7.3. Of this cohort, 76 men (with a median PSA level ranging from 0.03-134.60 ng/mL) had been treated solely with radiation therapy. Remarkably, 75 out of these 76 men had a positive scan, and in 32 cases, the positive findings were restricted to the prostate without any extraprostatic detection. On the flip side, the scans revealed 18F-rhPSMA-7.3-sensitive pelvic nodes in 25% of these patients (pts), and distant lesions in 43%.
The study revealed that 18F-rhPSMA-7.3 has high detection rates in men who have only received radiation therapy and are experiencing prostate cancer recurrence. Although 42% showed recurrence limited to the prostate, up to half of the pts had 18F-rhPSMA-7.3-reactive lesions in distant extrapelvic areas. This finding could significantly impact therapeutic decision-making, particularly when salvage therapy to the prostate is under consideration.
Source: https://www.auajournals.org/doi/10.1097/JU.0000000000003278.13
Clinical Trial: https://classic.clinicaltrials.gov/ct2/show/NCT04186845
Helfand, Brian T.; MP40-13 18F-RHPSMA-7.3 DETECTION RATES IN PATIENTS WITH RECURRENCE OF PROSTATE CANCER FOLLOWING PRIMARY TREATMENT WITH RADIATION THERAPY: RESULTS FROM THE SPOTLIGHT STUDY, Journal of Urology: April 2023 – Volume 209 – Issue Supplement 4 doi: 10.1097/JU.0000000000003278.13
