First PSMA-Targeted PET Drug for Prostate Cancer Approved by FDA

The FDA has approved Gallium 68 PSMA-11 (Ga 68 PSMA-11) as the first ever drug for positron emission tomography (PET) imaging of prostate-specific membrane antigen (PSMA) positive lesions in men with prostate cancer.¹

The approved indication for the drug is for use in patients with suspected prostate cancer metastasis who are potentially curable through surgery or radiation therapy. Ga 68 PSMA-11 is also indicated for patients with suspected recurrence based on an elevated prostate-specific antigen (PSA) level.

GA 68 PSMA-11 is a radioactive diagnostic agent that is administered via intravenous injection. The drug binds to PSMA and through PET imaging reveals the presence of PSMA-positive lesions.

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

Approval for Ga 68 PSMA-11 is based on findings from 2 prospective clinical trials comprising a total of 960 men with prostate cancer who all received an injection of Ga 68 PSMA-11. Updated findings are expected to be presented at the upcoming 2020 American Society of Hematology (ASH) Annual Meeting.

In the first study, 325 men who were candidates for surgery underwent PET/CT or PET/MRI scans with Ga 68 PSMA-11. Of the patients who proceeded to surgery, men with PSMA-positive pelvic lymph node readings had a clinically important rate of metastatic disease as confirmed by surgical pathology.

The results were expected to spare some of these men from undergoing unnecessary surgery.

The second study included 635 men with rising serum PSA levels following initial prostatectomy, radiotherapy, or both, indicating biochemical evidence of a recurrence. All patients received a PET/CT or PET/MRI scan with Ga 68 PSMA-11 and 74% were found to have at least 1 positive lesion in at least 1 region of the body.^1,2 Among those who also had correlative tissue pathology and serial PSA levels, 91% of cases of local recurrence or metastasis were confirmed.

In the patients with higher PSA levels, detection rates were higher at 84% for those with levels from 1.0 to less than 2.0 ng/mL, 86% for 2.0 to less than 5.0 ng/mL, and 97% for 5.0 ng/mL or more (P <.001).²

Such findings were expected to have an impact on subsequent approaches to therapy for these patients.

No serious adverse events were considered related to Ga 68 PSMA-11 but the most common events reported on the trials were nausea, diarrhea, and dizziness.

Ga 68 PSMA-11 is associated with an increased cumulative radiation exposure, which could be associated with an increased risk for cancer.

The FDA granted approval for Ga 68 PSMA-11 to the University of California, Los Angeles (UCLA) and the University of California, San Francisco (UCSF).^1,3

“It is rare for academic institutions to obtain FDA approval of a drug, and this unique collaboration has led to what is one of the first co-approvals of a drug at 2 institutions,” said Thomas Hope, MD, an associate professor at UCSF, in a statement. “We hope that this first step will lead to a more widespread availability of this imaging test to men with prostate cancer throughout the country.”

Currently, UCSF and UCLA are the only 2 medical centers in the United States that can offer PSMA PET through this approval.

“UCLA and UCSF researchers studied PSMA PET to provide a more effective imaging test for men who have prostate cancer,” added Jeremie Calais, MD, MSc, an assistant professor at the David Geffen School of Medicine at UCSF, in a statement. “Because the PSMA PET scan has proven to be more effective in locating these tumors, it should become the new standard of care for men who have prostate cancer, for initial staging or localization of recurrence.”

_References

1. _{FDA Approves First PSMA-Targeted PET Imaging Drug for Men with Prostate Cancer. News release. FDA. December 1, 2020. Accessed December 2, 2020. https://bit.ly/2VvhoA0}
2. _{Fendler WP, Calais J, Eiber M, et al. Assessment of 68Ga-PSMA-11 PET Accuracy in Localizing Recurrent Prostate Cancer: A Prospective Single-Arm Clinical Trial. JAMA Oncol. 2019;5(6):856-863. doi:10.1001/jamaoncol.2019.0096}
3. _{UCSF, UCLA Gain FDA Approval for Prostate Cancer Imaging Technique. University of California San Francisco. December 1, 2020. Accessed December 2, 2020. https://bit.ly/2KQAUoj}