FDA Approves Gallium 68 PSMA-11 for Prostate Cancer

The FDA approved the first drug for PET imaging of prostate-specific membrane antigen (PSMA) positive lesions in men with prostate cancer, Gallium 68 PSMA-11 (Ga 68 PSMA-11).

“Ga 68 PSMA-11 is an important tool that can aid health care providers in assessing prostate cancer,” Alex Gorovets, MD, acting deputy director of the Office of Specialty Medicine in FDA’s Center for Drug Evaluation and Research, said in press releasee. “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.”

The FDA based its decision on the safety and efficacy of Ga 68 PSMA-11 proven in 2 prospective clinical trials with a total of 960 men with prostate cancer who each received 1 injection of the drug.

In the first trial, 325 patients who were candidates for surgical removal of the prostate gland and pelvic lymph nodes and were considered at higher risk for metastasis underwent PET/CT or PET/MRI scans performed with Ga 68 PSMA-11. Of the patients who went on to undergo surgery, Ga 68 PSMA-11 PET demonstrated a clinically important rate of metastatic cancer confirmed by surgical pathology in patients with positive readings in the pelvic lymph nodes.

“The availability of this information prior to treatment is expected to have important implications for patient care. For example, it may spare certain patients from undergoing unnecessary surgery,” the FDA states in its release.

In the second trial, 635 patients who had rising serum PSA levels after initial prostate surgery or radiotherapy, 74% had at least 1 positive lesion detected by Ga 68 PSMA-11 PET in at least 1 body region. In total, 91% of atients with positive Ga 68 PSMA-11 PET readings who had correlative tissue pathology from biopsies, who also had results from baseline or follow-up imaging by conventional methods, and serial PSA levels available for comparison, also had local recurrence or metastasis of prostate cancer confirmed.

“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,” the agency added.

No serious adverse events (AEs) were attributed to Ga 68 PSMA-11. The most common AEs included nausea, diarrhea, and dizziness.

The FDA warned there may be a risk for misdiagnosis, “because Ga 68 PSMA-11 binding may occur in other types of cancer as well as certain non-malignant processes which may lead to image interpretation errors. There are radiation risks because Ga 68 PSMA-11 contributes to a patient’s overall long-term cumulative radiation exposure, which is associated with an increased risk for cancer.”

The drug, which is a radioactive diagnostic agent that is administered in the form of an intravenous injection, is indicated for patients with suspected prostate cancer metastasis who are potentially curable by surgery or radiation therapy and for those with suspected prostate cancer recurrence based on elevated serum prostate-specific antigen (PSA) levels. Ga 68 PSMA-11 binds to PSMA once administered and can be imaged by PET to indicate the presence of PSMA-positive prostate cancer lesions in the tissues of the body.

F 18 fluciclovine and C 11 choline are 2 additional PET drugs that are approved for prostate cancer imaging, the FDA noted; however, they are only approved for use in patients with suspected cancer recurrence.

Reference:

FDA News Release. FDA Approves First PSMA-Targeted PET Imaging Drug for Men with Prostate Cancer. Published December 1, 2020. https://www.fda.gov/news-events/press-announcements/fda-approves-first-psma-targeted-pet-imaging-drug-men-prostate-cancer?utm_medium=email&utm_source=govdelivery. Accessed: December 1, 2020.