Impact of 18F-flotufolastat PET on management of patients with recurrent prostate cancer: Data from the SPOTLIGHT study.

Authors

null

Przemyslaw Twardowski

Saint John’s Cancer Institute at Providence Saint John’s Health Center, Santa Monica, CA

Organizations

Saint John’s Cancer Institute at Providence Saint John’s Health Center, Santa Monica, CA

Research Funding

Blue Earth Diagnostics

Background: 18F-Flotufolastat (18F-rhPSMA-7.3) is a newly approved high affinity PSMA-targeting PET radiopharmaceutical for diagnostic imaging in patients with prostate cancer (PCa). SPOTLIGHT (NCT04186845) evaluated 18F-flotufolastat in patients with recurrent PCa. Here, we report available SPOTLIGHT data to assess the impact of 18F-flotufolastat on planned treatment after curative-intent primary therapy. Methods: Patients underwent PET 50–70 min after IV administration of 296 MBq 18F-flotufolastat. The protocol instructed onsite investigators to record patients’ management plans (MP) before and after 18F-flotufolastat PET. These MP were compared and categorized as: ‘no change’, ‘major change’, ‘other change’, ‘additional information required’ or ‘intended plan not valid’. A ‘major change’ was defined as a change to treatment modality (e.g., salvage radiation therapy [RT] to systemic therapy), while ‘other change’ represented a change within a modality (e.g., modified RT field). Plans categorized as ‘no change’, ‘major change’ or ‘other change’ were considered evaluable. All imaging data were subsequently submitted for blinded image evaluation (BIE) by 3 central readers. Results: Of 389 patients who had 18F-flotufolastat PET, 97 had sufficient MP data for evaluation. These 97 patients were comparable to the overall population in terms of prior treatment (84% vs 79%, respectively, were post-prostatectomy), Gleason Score (63% vs 60% had Score 7), and median baseline PSA (0.8 vs 1.1 ng/mL). Moreover, BIE data show the detection rate in this subgroup (81/97; 84%) to be equivalent to that in the overall population (322/389; 83%). Most patients, 86/97 (89%) had a change to their MP post-scan. A ‘major change’ was noted for 78 (80%) patients, while 8 (8.2%) had an ‘other change’ (Table). Onsite imaging reads show that both positive and negative 18F-flotufolastat scans influenced MP. While 88% of revisions occurred after a positive scan, 75% of those whose MP were revised to watchful waiting (WW) had negative scans. All patients with MP revised from salvage therapy to non-curative systemic therapy had distant/extrapelvic 18F-flotufolastat-avid lesions. Conclusions:18F-Flotufolastat located recurrence sites in the majority of patients with recurrent PCa, frequently resulting in major changes to MP. Treatment based on visualization of 18F-flotufolastat-avid lesions may facilitate optimal targeting of recurrence sites and avoid futile salvage therapy. Future studies of the outcome of such MP changes are warranted. Clinical trial information: NCT04186845.

Change in MP (N=97)n (%)
No Change11 (11)
Major Change78 (80)
Salvage or non-curative systemic therapy to WW8 (8.2)
Salvage therapy to non-curative systemic therapy15 (15)
WW to salvage or non-curative therapy32 (33)
Alternative major change23 (24)
Other Change8 (8.2)
Modified RT field5 (5.2)
Modified ADT regimen or alternative other change3 (3.1)

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Abstract Details

Meeting

2024 ASCO Genitourinary Cancers Symposium

Session Type

Poster Session

Session Title

Poster Session A: Prostate Cancer

Track

Prostate Cancer - Advanced,Prostate Cancer - Localized

Sub Track

Diagnostics and Imaging

Clinical Trial Registration Number

NCT04186845

Citation

J Clin Oncol 42, 2024 (suppl 4; abstr 38)

DOI

10.1200/JCO.2024.42.4_suppl.38

Abstract #

38

Poster Bd #

A17

Abstract Disclosures