In adults, the recommended amount of radioactivity to be administered for PET is 111 MBq to 259 MBq (3 mCi to 7 mCi) administered as an intravenous bolus injection.
- Use aseptic technique and radiation shielding when withdrawing and administering Ga 68 PSMA-11 Injection.
- Calculate the necessary volume to administer based on calibration time and required dose.
- Inspect Ga 68 PSMA-11 Injection visually for particulate matter and discoloration before administration. Do not use the drug if the solution contains particulate matter or is discolored.
- Ga 68 PSMA-11 Injection may be diluted with sterile 0.9% Sodium Chloride Injection, USP.
- Assay the final dose immediately before administration to the patient in a dose calibrator.
- After injection of Ga 68 PSMA-11 Injection, administer an intravenous flush of sterile 0.9% Sodium Chloride Injection, USP to ensure full delivery of the dose.
- Dispose of any unused drug in a safe manner in compliance with applicable regulations.
- Unless contraindicated, a diuretic expected to act within the uptake time period may be administered at the time of radiotracer injection to potentially decrease artifact from radiotracer accumulation in the urinary bladder and ureters.
Androgen deprivation therapy and other therapies targeting the androgen pathway
Androgen deprivation therapy (ADT) and other therapies targeting the androgen pathway, such as androgen receptor antagonists, can result in changes in uptake of Ga 68 PSMA-11 in prostate cancer. The effect of these therapies on performance of Ga 68 PSMA-11 PET has not been established.
Risk Summary
Ga 68 PSMA-11 Injection is not indicated for use in females. There are no available data with Ga 68 PSMA-11 Injection use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes. All radiopharmaceuticals, including Ga 68 PSMA-11 Injection, have the potential to cause fetal harm depending on the fetal stage of development and the magnitude of the radiation dose. Animal reproduction studies have not been conducted with Ga 68 PSMA-11 Injection.
Risk Summary
Ga 68 PSMA-11 Injection is not indicated for use in females. There are no data on the presence of Ga 68 PSMA-11 in human milk, the effect on the breastfed infant, or the effect on milk production.
Distribution
Intravenously injected Ga 68 PSMA-11 is cleared from the blood and is accumulated preferentially in the liver (15%), kidneys (7%), spleen (2%), and salivary glands (0.5%). Ga 68 PSMA-11 uptake is also seen in the adrenals and prostate. There is no uptake in the cerebral cortex or in the heart, and usually lung uptake is low.
Elimination
A total of 14% of the injected dose is excreted in urine in the first 2 hours post-injection.
PSMA-PreRP
This two-center study enrolled 325 patients with biopsy-proven prostate cancer who were considered candidates for prostatectomy and pelvic lymph node dissection. All enrolled patients met at least one of the following criteria: serum prostate-specific antigen (PSA) of at least 10 ng/mL, tumor stage cT2b or greater, or Gleason score greater than 6. Each patient received a single Ga 68 PSMA-11 PET/CT or PET/MR from mid-thigh to skull base.
A total of 123 patients (38%) proceeded to standard-of-care prostatectomy and template pelvic lymph node dissection and had sufficient histopathology data for evaluation (evaluable patients). Three members of a pool of six central readers independently interpreted each PET scan for the presence of abnormal Ga 68 PSMA-11 uptake in pelvic lymph nodes located in the common iliac, external iliac, internal iliac, and obturator subregions bilaterally as well as in any other pelvic location. The readers were blinded to all clinical information except for the history of prostate cancer prior to definitive treatment. Extrapelvic sites and the prostate gland itself were not analyzed in this study. For each patient, Ga 68 PSMA-11 PET results and reference standard histopathology obtained from dissected pelvic lymph nodes were compared by region (left hemipelvis, right hemipelvis, and other).
For the 123 evaluable patients, the mean age was 65 years (range 45 to 76 years), and 89% were white. The median serum PSA was 11.8 ng/mL. The summed Gleason score was 7 for 44%, 8 for 20%, and 9 for 31% of the patients, with the remainder of the patients having Gleason scores of 6 or 10.
Table 5 compares majority PET reads to pelvic lymph node histopathology results at the patient-level with region matching, such that at least one true positive region defines a true positive patient. As shown, approximately 24% of subjects studied were found to have pelvic nodal metastases based on histopathology (95% confidence interval: 17%, 32%).
Table 5: Patient-Level Performance of Ga 68 PSMA-11 PET for Detection of Pelvic Lymph Node Metastasis
with region matching where at least one true positive region defines a true positive patient
in the PSMA-PreRP Study (n=123)
| Histopathology | Predictive value
PPV: positive predictive value, NPV: negative predictive value (95% CI)
|
|---|
| Positive | Negative |
|---|
| PET scan | Positive | 14 | 9 | PPV
61% (41%, 81%)
|
| Negative | 16 | 84 | NPV
84% (79%, 91%)
|
| Total | 30 | 93 | |
Diagnostic performance
(95% CI)
| Sensitivity
47% (29%, 65%)
| Specificity
90% (84%, 96%)
|
Among the pool of six readers, sensitivity ranged from 36% to 60%, specificity from 83% to 96%, positive predictive value from 38% to 80%, and negative predictive value from 80% to 88%.
In an exploratory subgroup analysis based on summed Gleason score, there was a numerical trend toward more true positives in patients with Gleason score of 8 or higher compared to those with Gleason score of 7 or lower.
An exploratory analysis was performed to estimate the sensitivity and specificity for pelvic nodal metastasis detection in all scanned patients, including the patients who were lacking histopathology reference standard. An imputation method was used based on patient-specific factors. This exploratory analysis resulted in an imputed sensitivity of 47%, with a 95% confidence interval ranging from 38% to 55%, and an imputed specificity of 74%, with a 95% confidence interval ranging from 68% to 80% for all patients imaged with Ga 68 PSMA-11 PET.
PSMA-BCR
This two-center study enrolled 635 patients with biochemical evidence of recurrent prostate cancer after definitive therapy, defined by serum PSA of >0.2 ng/mL more than 6 weeks after prostatectomy or by an increase in serum PSA of at least 2 ng/mL above nadir after definitive radiotherapy. All patients received a single Ga 68 PSMA-11 PET/CT or PET/MR from mid-thigh to skull base. Three members of a pool of nine independent central readers evaluated each scan for the presence and regional location (20 subregions grouped into four regions) of abnormal Ga 68 PSMA-11 uptake suggestive of recurrent prostate cancer. The readers were blinded to all clinical information other than type of primary therapy and most recent serum PSA level.
A total of 469 patients (74%) had at least one positive region detected by Ga 68 PSMA-11 PET majority read. The distribution of Ga 68 PSMA-11 PET positive regions was 34% bone, 25% prostate bed, 25% pelvic lymph node, and 17% extrapelvic soft tissue. Two hundred and ten patients had composite reference standard information collected in a PET positive region (evaluable patients), consisting of at least one of the following: histopathology, imaging (bone scintigraphy, CT, or MRI) acquired at baseline or within 12 months after Ga 68 PSMA-11 PET, or serial serum PSA. Composite reference standard information for Ga 68 PSMA-11 PET negative regions was not systematically collected in this study.
In the 210 evaluable patients, the mean age was 70 years (range 49 to 88 years) and 82% were 65 years of age or older. White patients made up 90% of the group. The median serum PSA was 3.6 ng/mL. Prior treatment included radical prostatectomy in 64% and radiotherapy in 73%.
Of the 210 evaluable patients, 192 patients (91%) were found to be true positive in one or more regions against the composite reference standard (95% confidence interval: 88%, 95%). Among the pool of nine readers used in the study, the proportion of patients who were true positive in one or more regions ranged from 82% to 97%. The prostate bed had the lowest proportion of true positive results at the region-level (76% versus 96% for non-prostate regions).
An exploratory analysis was also performed in which Ga 68 PSMA-11 PET positive patients who lacked reference standard information were imputed using an estimated likelihood that at least one location-matched PET positive lesion was reference standard positive based on patient-specific factors. In this exploratory analysis, 340 of 475 patients (72%) were imputed as true positive in one or more regions (95% confidence interval: 68%, 76%).
In another exploratory analysis using the same imputation approach for PET positive patients who lacked reference standard information, 340 of 635 patients (54%) were correctly detected as true positive (95% confidence interval: 50%, 57%) among all BCR patients who received a PET scan, whether it was read as positive or negative.
The likelihood of identifying a Ga 68 PSMA-11 PET positive lesion in this study generally increased with higher serum PSA level. Table 6 shows the patient-level Ga 68 PSMA-11 PET results stratified by serum PSA level. The mean time between PSA measurement and PET scan was 40 days with a range of 0 to 367 days. Percent PET positivity was calculated as the proportion of patients with a positive Ga 68 PSMA-11 PET out of all patients scanned. Percent PET positivity includes patients determined to be either true positive or false positive as well as those in whom such determination was not made due to the absence of composite reference standard data.
Table 6: Patient-Level Ga 68 PSMA-11 PET Results and Percent PET Positivity Stratified by Serum PSA Level in the PSMA-BCR Study (n=628)
7 patients were excluded from this table due to protocol deviations
PSA
(ng/mL)
| PET positive patients | PET negative patients | Percent PET positivity
Percent PET positivity = PET positive patients/total patients scanned (95% CI)
|
|---|
| Total | TP
TP: true positive, FP: false positive | FP
| Without reference standard |
|---|
| With reference standard |
|---|
| <0.5 | 48 | 11 | 1 | 36 | 87 | 36%
(27%, 44%)
|
| 12 |
| ≥0.5 and <1 | 44 | 15 | 3 | 26 | 35 | 56%
(45%, 67%)
|
| 18 |
| ≥1 and <2 | 71 | 29 | 1 | 41 | 15 | 83%
(75%, 91%)
|
| 30 |
| ≥2 | 299 | 137 | 13 | 149 | 29 | 91%
(88%, 94%)
|
| 150 |
| Total | 462 | 192 | 18 | 252 | 166 | 74%
(70%, 77%)
|
| 210 |
Storage
Store Ga 68 PSMA-11 Injection upright in a lead shielded container at 25°C (77°F); excursions are permitted from 15°C to 30°C (59°F to 86°F). Store Ga 68 PSMA-11 Injection within the original container in radiation shielding.
Handling
Receipt, transfer, handling, possession, or use of this product is subject to the radioactive material regulations and licensing requirements of the U.S. Nuclear Regulatory Commission, Agreement States, or Licensing States as appropriate.
Adequate Hydration
Instruct patients to drink a sufficient amount of water to ensure adequate hydration before their PET study and urge them to drink and urinate as often as possible during the first hours following the administration of Ga 68 PSMA-11 Injection, in order to reduce radiation exposure
[see
Dosage and Administration (2.3) and
Warnings and Precautions (5.2)]
.
Manufactured and Distributed by:
University of California, Los Angeles
UCLA Biomedical Cyclotron Facility
780 Westwood Plaza
Los Angeles, CA 90095
(310) 794-7638