WASHINGTON — The FDA approved the first PET imaging agent that targets prostate-specific membrane antigen (PSMA) for evaluation of men with suspected prostate cancer, a potential game-changing advance, according to experts.
The approval makes gallium (Ga) 68 PSMA-11 available for use in patients with newly diagnosed, potentially curable prostate cancer that has high-risk characteristics for metastasis, and for patients with suspected recurrent prostate cancer. Administered prior to PET imaging, the radioactive diagnostic agent binds to prostate cancer lesions expressing PSMA.
“Ga-68 PSMA-11 is an important tool that can aid healthcare providers in assessing prostate cancer,” said Alex Gorovets, MD, of the FDA Center for Drug Evaluation and Research, in announcing the decision. “With this first approval of a PSMA-targeted PET imaging drug for men with prostate cancer, providers now have a new imaging approach to detect whether or not the cancer has spread to other parts of the body.”
F-18 fluciclovine and C-11 choline also have FDA-approved indications for prostate cancer, but the indications apply only to patients with suspected prostate cancer recurrence. In a clinical trial that directly compared Ga-68 PSMA-11 and F-18 fluciclovine, the PSMA-targeted agent detected significantly more prostate cancers in men who had recurrence after radical prostatectomy.
“Because the PSMA PET scan has proven to be more effective in locating these tumors, it should be the new standard of care for men who have prostate cancer, for initial staging or localization of recurrence,” trial investigator Jeremie Calais, MD, of the University of California Los Angeles (UCLA), said in a separate statement.
Peter Carroll, MD, of the University of California San Francisco (UCSF), added, “I believe PSMA PET imaging in men with prostate cancer is a game changer because its use will lead to better, more efficient and precise care.” Carroll was an investigator in a single-arm evaluation of Ga-68 PSMA-11.
The FDA based approval primarily on two single-arm evaluations of Ga-68 PSMA-11 involving a total of 960 men with prostate cancer. One study included 325 men with newly diagnosed prostate cancer with high-risk characteristics for metastasis. The results showed that men with positive PET PSMA scans had “a clinically important rate of metastatic cancer confirmed by surgical pathology.”
“The availability of this information prior to treatment is expected to have important implications for care,” according to the FDA statement. “For example, it may spare certain patients from undergoing unnecessary surgery.”
In the second study, 635 men with rising PSA levels after radical prostatectomy or definitive radiation therapy underwent PET imaging with Ga-68 PSMA-11, which revealed one or more positive lesions in three-fourths of the patients. When the PET imaging results were combined with biopsy or other information, 91% of positive cases were confirmed as local or metastatic recurrence.
“Thus, the second trial demonstrated that Ga-68 PSMA-11 PET can detect sites of disease in patients with biochemical evidence of recurrent prostate cancer, thereby providing important information that may impact the approach to therapy,” according to the FDA.
The FDA granted the approval to UCLA and UCSF, a rarity in the approval process, said Thomas Hope, MD, of UCSF, who called the joint effort of the two institutions a “unique collaboration.”