First PSMA-Targeted PET Imaging Agent Approved by FDA for Men With Prostate Cancer
Posted: Wednesday, December 2, 2020
On December 1, the U.S. Food and Drug Administration approved the radioactive diagnostic agent gallium 68 PSMA-11 (Ga 68 PSMA-11), the first drug for PET imaging 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 who are potentially curable by surgery or radiation therapy. It also is indicated for patients with suspected prostate cancer recurrence based on elevated serum PSA levels.
The safety and efficacy of Ga 68 PSMA-11 were evaluated in two prospective clinical trials with a total of 960 men with prostate cancer, who each received one injection of Ga 68 PSMA-11. In the first trial, 325 patients with biopsy-proven prostate cancer underwent PET/CT or PET/MRI scans performed with Ga 68 PSMA-11. These patients were candidates for surgical removal of the prostate gland and pelvic lymph nodes and were considered at higher risk for metastasis. Among the patients who proceeded to surgery, those with positive readings in the pelvic lymph nodes on Ga 68 PSMA-11 PET had a clinically relevant rate of metastatic cancer confirmed by surgical pathology. The availability of this information prior to treatment may spare certain patients from undergoing unnecessary surgery.
The second trial enrolled 635 patients who had rising serum PSA levels after initial prostate surgery or radiotherapy and thus 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 detected by Ga 68 PSMA-11 PET in at least one body region (bone, prostate bed, pelvic lymph node, or extrapelvic soft tissue). In patients with positive Ga 68 PSMA-11 PET readings who had correlative tissue pathology from biopsies, results from baseline or follow-up imaging by conventional methods, and serial PSA levels available for comparison, local recurrence or metastasis of prostate cancer was confirmed in an estimated 91% of cases.
The most common adverse reactions to Ga 68 PSMA-11 were nausea, diarrhea, and dizziness.