Diagnostic Capability in Relapsed Prostate Cancer Improved with ¹⁸F-DCFPyL PET/CT Imaging

Web Exclusives

The US Food and Drug Administration recently approved 18F-DCFPyL, a prostate-specific membrane antigen (PSMA)-targeted positron emission tomography (PET) imaging agent, for men with prostate cancer, to aid in assessing prostate cancer lesions.1 Its indications for use are for patients with suspected prostate cancer recurrence based on elevated levels of serum prostate-specific antigen (PSA) and for suspected prostate cancer metastasis.1 18F-DCFPyL is administered by intravenous injection and will bind to PSMA, which is elevated in prostate cancer cells.1 18F-DCFPyL emits positrons, which PET can then image to indicate where PSMA-positive prostate cancer lesions are in the body.1 PSMA-targeted PET/computed tomography (CT) has proven to be superior to conventional imaging when evaluating patients with biochemically recurrent prostate cancer with low PSA after they have had local therapy.2

At the American Society of Clinical Oncology 2021 annual meeting, Pouliot and colleagues presented the results of an analysis of PSMA-targeted 18F-DCFPyL PET/CT accuracy when compared with prespecified standard of truth (SOT) using data from the CONDOR phase 3 study.2 SOT included histopathology, correlative imaging findings as determined by 2 central readers, or post-radiation PSA response.2 The study primary end point was correct localization rate (CLR) defined as positive predictive value (PPV) with anatomic lesion co-localization between 18F-DCFPyL and SOT.2 The secondary end points were percentage of participants with a change in intended prostate cancer treatment due to 18F-DCFPyL PET/CT imaging, the change from pre- to post–18F-DCFPyL dosing in blood pressure and heart rate, and collection of concomitant medications and medical procedures.3

The CONDOR study enrolled 208 men who had rising PSA levels (median PSA, 0.8 ng/mL) after local therapy and a negative or equivocal conventional imaging (bone scintigraphy, CT/magnetic resonance imaging [MRI], 18F-fluciclovine).2 The patients were given a single injection of 18F-DCFPyL with a PET/CT performed 1 to 2 hours after the injection. If a patient had a positive scan, they were scheduled for follow-up within 60 days to verify suspected lesions using a composite SOT.2 The CONDOR study achieved its primary end point with a CLR between 84.8% and 87% among 3 independent, blinded central 18F-DCFPyL PET/CT reviewers against the composite SOT. When the performance of 18F-DCFPyL by CLR and PPV was examined, it was found to have been maintained across the 3 SOT categories.2 The PSA response was 100% for both CLR and PPV; histopathology CLR was 78.6% to 82.8% and PPV was 92.9% to 93.3%; and correlative imaging was 86.1% to 88.6% for CLR and 87.0% to 89.5% for PPV. When further analysis was performed for correlative imaging, CLR remained high for each of the modalities used: MRI CLR was 80.0% to 86.7%, CT CLR was 80.0% to 100%, and F 18 fluciclovine PET/CT CLR was 86.8% to 90.9%.2

References

  1. US Food and Drug Administration. FDA approves PSMA-targeted imaging drug for men with prostate cancer. www.fda.gov/drugs/drug-safety-and-availability/fda-approves-second-psma-targeted-pet-imaging-drug-men-prostate-cancer. Accessed September 27, 2021.
  2. Pouliot F, Gorin MA, Rowe SP, et al. PSMA-targeted imaging with 18F-DCFPyL-PET/CT in patients (pts) with biochemically recurrent prostate cancer (PCa): a phase III study (CONDOR)—a subanalysis of correct localization rate (CLR) and positive predictive value (PPV) by standard of truth. J Clin Oncol. 2021;39:33-33.
  3. Clinicaltrials.gov. Study of 18F-DCFPyL PET/CT imaging in patients with suspected recurrence of prostate cancer. Updated June 14, 2021. https://clinicaltrials.gov/ct2/show/NCT03739684. Accessed September 27, 2021.

Related Articles