Today, the U.S. Food and Drug Administration approved Gallium 68 PSMA-11 (Ga 68 PSMA-11) – the first drug for positron emission tomography (PET) of prostate-specific membrane antigen (PSMA) -positive lesions in men with prostate cancer.
Ga 68 PSMA-11 is indicated for patients with suspected prostate cancer metastasis (when cancer cells spread from where they first formed to another part of the body) who may be cured by surgery or radiation therapy. Ga 68 PSMA-11 is also indicated for patients with suspected recurrence of prostate cancer due to elevated PSA (serum prostate-specific antigen) levels. Ga 68 PSMA-11 is a radioactive diagnostic agent that is given in the form of an intravenous injection.
Ga 68 PSMA-11 is an important tool that can aid healthcare providers in prostate cancer assessment. With this first approval of a PSMA-targeted PET imaging drug for men with prostate cancer, providers now have a new imaging approach to determine whether or not the cancer has spread to other parts of the body. “
Alex Gorovets, MD, assistant director of the Office of Specialty Medicine at the FDA Center for Drug Evaluation and Research
Prostate cancer is the third most common cancer in the United States. According to the National Cancer Institute, there will be an estimated more than 190,000 new cases of prostate cancer and an estimated 33,000 deaths from the disease in 2020. While computed tomography (CT) scans, magnetic resonance imaging (MRI) scans, and bone scans are conventional methods commonly used to image patients with prostate cancer, these approaches are limited in detecting prostate cancer lesions. F 18 fluciclovin and C 11 choline are two other PET drugs that are approved for use in prostate cancer imaging. However, they are only approved for use in patients who are suspected of having cancer recurrence.
Once administered by injection, Ga 68 PSMA-11 binds to PSMA, which is an important pharmacological target for prostate cancer imaging since prostate cancer cells normally contain elevated levels of antigen. As a radioactive drug that emits positrons, Ga 68 PSMA-11 can be imaged by PET to indicate the presence of PSMA positive prostate cancer lesions in tissues of the body.
The safety and efficacy of Ga 68 PSMA-11 were evaluated in two prospective clinical studies involving a total of 960 men with prostate cancer who were each given one injection of Ga 68 PSMA-11. In the first study, 325 patients with biopsy-proven prostate cancer underwent PET / CT or PET / MRI scans with Ga 68 PSMA-11. These patients were candidates for surgical removal of the prostate and pelvic lymph nodes and were at greater risk of metastasis. Among the patients who underwent surgery, those with positive readings in the pelvic lymph nodes on Ga 68 PSMA-11 PET had a clinically important rate of metastatic cancer confirmed by the surgical pathology. The availability of this information prior to treatment is expected to have important implications for patient care. For example, it can save certain patients from having to undergo unnecessary operations.
The second study included 635 patients who had rising serum PSA levels after initial prostate surgery or radiation therapy and thus had biochemical evidence of recurrent prostate cancer. All of these patients received a single Ga 68 PSMA-11 PET / CT scan or PET / MR scan. Based on the scans, 74% of these patients had at least one positive lesion, which was detected by Ga 68 PSMA-11 PET in at least one region of the body (bone, prostate bed, pelvic lymph nodes, or extra-pelvic soft tissue).
In patients with positive Ga 68 PSMA-11 PET values showing correlative tissue pathology from biopsies, results from baseline or follow-up imaging using conventional methods and serial PSA levels available for comparison were shown in local recurrence or metastasis of prostate cancer confirms an estimated 91% of cases. The second study showed that Ga 68 PSMA-11 PET can identify disease foci in patients with biochemical evidence of recurrent prostate cancer, thereby providing important information that can influence the therapeutic approach.
No serious side effects were ascribed to Ga 68 PSMA-11. The most common side effects with Ga 68 PSMA-11 were nausea, diarrhea, and dizziness. There is a risk of misdiagnosis as Ga 68 PSMA-11 binding can occur in other cancers as well as in certain non-malignant processes that can 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 of cancer.
The FDA approved the University of California at Los Angeles and the University of California at San Francisco.
US Food and Drug Administration