A radioactive diagnostic agent has been approved by the U.S. Food and Drug Administration for use in patients with prostate cancer, but only for those treated at two institutions in California.
The product, Gallium 68 PSMA-11 (Ga 68 PSMA-11), is the first agent approved specifically for use in positron-emission tomography (PET) imaging of prostate-specific membrane antigen (PSMA)–positive lesions in men with prostate cancer, the FDA noted.
This imaging approach can “detect whether or not the cancer has spread to other parts of the body,” commented Alex Gorovets, MD, acting deputy director of the Office of Specialty Medicine in the FDA’s Center for Drug Evaluation and Research.
Ga 68 PSMA-11 is indicated for use in patients with suspected prostate cancer metastasis whose conditions are potentially curable by surgery or radiotherapy and in patients with suspected prostate cancer recurrence, as determined on the basis of elevated serum prostate-specific antigen (PSA) levels.
Institutional use only
Ga 68 PSMA-11 has been approved for institutional use at the University of California, Los Angeles and the University of California, San Francisco under an academic new drug application (NDA).
The FDA approval was based partly on a clinical trial conducted by the UCSF and UCLA research teams on the effectiveness of PSMA-PET.
“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 coapprovals of a drug at two institutions,” said Thomas Hope, MD, an associate professor at UCSF. “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.”
Ga 68 PSMA-11 was developed outside the United States at the University of Heidelberg (Germany).
A commercial NDA from Telix Pharmaceuticals for TL591-CDx, a radiopharmaceutical cold kit for the preparation of Ga 68 PSMA-11 injection, is under consideration by the FDA.
The agency noted that two other PET diagnostic agents – fluciclovine F18 and choline C11 – are approved for prostate cancer imaging. However, they are only approved for use in patients with suspected cancer recurrence.
Trial results with PSMA-PET/CT
“PSMA-PET/CT is a novel molecular and functional imaging modality specific for prostate cancer cells that has good sensitivity and outstanding specificity in detecting metastasis,” commented T. Martin Ma, MD, PhD, of UCLA.
Dr. Ma presented a U.S. study on the technique at the recent annual meeting of the American Society for Radiation Oncology. That study showed that PSMA-PET/CT led to nodal upstaging in 19.7% of patients and metastasis upstaging in 9.4%.
He said these results were similar to those from the Australian proPSMA trial, which was published in The Lancet earlier this year. That trial found PSMA-PET/CT to be superior to conventional imaging with CT and bone scanning for primary staging of high-risk prostate cancer.
“These findings carry significant clinical implications and can affect treatment decision-making,” Dr. Ma commented.
“PSMA-PET has been a real game changer in high-risk prostate cancer and has implications in the various stages of prostate cancer management from diagnosis and staging to theranostics,” said Renu Eapen, MBBS, of Peter MacCallum Cancer Center, Melbourne, who was not involved in either study.
“PSMA-PET/CT has challenged conventional imaging in staging before curative-intent surgery or radiotherapy,” Dr. Eapen added.
The accuracy of PSMA-PET/CT was 27% higher than that of conventional imaging in the proPSMA trial, she noted in an interview last month. This superior accuracy can ultimately affect management. The imaging has additional benefits of lower radiation dose as well as reproducibility with high reporter agreement, potentially making it a “one-stop-shop” scan.