FDA Approves Piflufolastat for Detection of Metastasis and Recurrence in Prostate Cancer

The FDA has granted approval to piflufolastat F 18 (Pylarify) injection, a prostate-specific membrane antigen (PSMA)–targeted positron emission tomography (PET) imaging agent, to identify patients who may have metastasis or recurrence of prostate cancer.

Piflufolastat’s application for approval was supported by data from 2 pivotal studies, the phase 3 OSPREY clinical trial (NCT02981368), and the phase 3 CONDOR clinical trial (NCT03739684).¹

“The FDA approval of Pylarify is a significant milestone for Lantheus and the prostate cancer community in the United States. We believe PYLARIFY represents a paradigm shift in the identification and management of patients with suspected metastasis or recurrent prostate cancer, providing more accurate and earlier detection of disease than conventional imaging so that doctors, along with patients and their families, can make more informed treatment decisions,” said Mary Anne Heino, president, and chief executive officer of Lantheus. “I would like to thank the patients who participated in our clinical trials, the study investigators, and our employees, whose efforts made this achievement possible.”

Results from the OSPREY trial presented during the American Society of Clinical Oncology (ASCO) Genitourinary Cancers Symposium showed that the PSMA PET-CT imaging injection has the ability to identify occult disease and characterize the disease burden in patients with prostate cancer more accurately than conventional imaging. Further, the study showed that changes in the disease stage uncovered by the PSMA PET-CT imaging injection may have a direct impact on treatment decisions.²

In 117 men with radiologic evidence of local recurrence or metastatic disease on baseline anatomical imaging or whole-body bone scintigraphy who had a minimum of 1 lesion available for biopsy, the injection up-staged 58% those with stage M0 to M1 disease, as well as 16% of those who had disease a stages M1a, M1b, or M1c. Among those with M0 to M1 91% were confirmed by extra-pelvic biopsy.

According to study investigators led by Jeremy C. Durack, MD, MS, the study findings suggested that PSMA PET-CT imaging may be a useful tool for proper staging of men with prostate cancer regardless of the presence of metastasis.

Data from the CONDOR were presented at the 2020 ASCO Annual Meeting and showed that PSMA PET-CT imaging had a high correction localization rate (CLR) when detecting and localizing metastatic lesions in patients with recurrent prostate cancer, and it showed high positive predictive value (PPV).³

The study included 208 men who had a median prostate-specific antigen of 0.8 ng/mL. The CLR achieved was between 78.6-82.8% in the study subjects and the PPV was between 92.9-93.3%. The results were shown regardless of the CLR criterion used.

“Conventional imaging has significant limitations in detecting prostate cancer, both in initial staging and when the cancer has recurred or spread after initial primary treatment. Specifically, standard imaging poorly detects the early spread to distant organs, such as the lymph nodes, bones, and other organs,” said Michael J. Morris, MD, Prostate Cancer Section head, Genitourinary Medical Oncology, Memorial Sloan Kettering Cancer Center, and the lead study investigator in the CONDOR trial and Study Investigator in the OSPREY trial, in the press release.1 “PYLARIFY can detect the spread of disease well before standard imaging and can be a transformative diagnostic tool that helps clinicians develop treatment plans based on a much more accurate understanding of a patient’s distribution of disease.”

“We believe today’s approval is a game-changer for men facing prostate cancer," said Jamie Bearse, chief executive officer of ZERO - The End of Prostate Cancer, a Patient Advocacy Group, in a statement. "Having a diagnostic tool that allows doctors to see suspected metastatic or recurrent prostate cancer earlier, anywhere in the body, is a significant step forward and will have a tremendous impact on patients' lives.”

_References:

_{1. Lantheus receives U.S. FDA approval of PYLARIFY® (piflufolastat F 18) injection, the first and only commercially available psma pet imaging agent for prostate cancer. News release. May 27, 2021. Accessed May 27, 2021.}

_{2. Durack JC, Alva AS, Preston MA, et al. A prospective phase II/III study of PSMA-targeted 18F-DCFPyL-PET/CT in patients (pts) with prostate cancer (PCa) (OSPREY): A subanalysis of disease staging changes in PCa pts with recurrence or metastases on conventional imaging.
J Clin Oncol. 2021; 36 (suppl 6; abstr 32). doi: 10.1200/JCO.2021.39.6_suppl.32}

_{3. Pouliot F, Gorin MA, Rowe SP, et al. PSMA-targeted imaging with 18F-DCFPyL-PET/CT in patients (pts) withbiochemically recurrent prostate cancer (PCa): A phase 3 study (CONDOR)—A subanalysis of correct localization rate (CLR) and positive predictive value (PPV) by standard of truth. J Clin Oncol. 2021; 39 (suppl 15; abstr 5023). doi: 10.1200/JCO.2021.39.15_suppl.5023}