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Indium In 111 ProstaScint® (capromab pendetide) is indicated as a diagnostic imaging agent in newly-diagnosed patients with biopsy-proven prostate cancer, thought to be clinically-localized after standard diagnostic evaluation (e.g. chest x-ray, bone scan, CT scan, or MRI), who are at high-risk for pelvic lymph node metastases (see CLINICAL PHARMACOLOGY, Imaging Performance in Newly-Diagnosed Patients). It is not indicated in patients who are not at high risk.
Indium In 111 ProstaScint® is also indicated as a diagnostic imaging agent in postprostatectomy patients with a rising PSA and a negative or equivocal standard metastatic evaluation in whom there is a high clinical suspicion of occult metastatic disease. The imaging performance of Indium In 111 ProstaScint® following radiation therapy has not been studied.
The information provided by Indium In 111 ProstaScint® imaging should be considered in conjunction with other diagnostic information. Scans that are positive for metastatic disease should be confirmed histologically in patients who are otherwise candidates for surgery or radiation therapy unless medically contraindicated. Scans that are negative for metastatic disease should not be used in lieu of histological confirmation.
DOSAGE AND ADMINISTRATION
The patient dose of the radiolabel must be measured in a dose calibrator prior to administration.
The recommended dose of ProstaScint® (capromab pendetide) is 0.5 mg radiolabeled with 5 mCi of Indium In 111 chloride. Each dose is administered intravenously over 5 minutes and should not be mixed with any other medication during its administration. Indium In 111 ProstaScint®may be readministered following infiltration or a technically inadequate scan; however, it is not indicated for readministration for the purpose of assessment of response to treatment (see INDICATIONS AND USAGE).
Each ProstaScint® kit is a unit dose package. After radiolabeling with Indium In 111, the entire Indium In 111 ProstaScint®dose should be administered to the patient. Reducing the dose of Indium In 111, unlabeled ProstaScint®, or Indium In 111 ProstaScint® may adversely impact imaging results and is, therefore, not recommended.
Parenteral drug products should be inspected visually for particulate matter and discoloration prior to administration, whenever solution and container permit.
The estimated absorbed radiation doses to an average adult patient from an intravenous injection of ProstaScint® labeled with 5 mCi of Indium In 111 are shown in TABLE 6. Total dose estimates include absorbed radiation doses from both Indium In 111 and the Indium In 114m radiocontaminant. A level of 0.06% of Indium In 114m was utilized for the dose estimates presented in TABLE 6.
TABLE 6 : ESTIMATED AVERAGE ABSORBED RADIATION DOSE IN
ADULT PATIENTS FROM INTRAVENOUS ADMINISTRATION OF PROSTASCINT® LABELED
WITH 5 mCi (185 MBq) OF INDIUM IN 111 CHLORIDEa
|Organ||Averag Dose (rad/5 mCi)||Average Dose (mGy/ 185MBq)|
|Urine Bladder wall||2.2||22|
|Gall Bladder Wall||7.3||73|
|Upper Large Intestine Wall||5.0||50|
|Lower Large Intestine Wall||7.6||76|
|aBased on data from 21 patients who received doses of ProstaScint® labeled with a mean (±SD) Indium In 111 dose of 4.6 ±1.0 mCi.|
Directions for Radiolabeling ProstaScint® (Capromab Pendetide) with Indium In 111 Chloride
Proper aseptic techniques and precautions for handling radioactive materials should be employed. Waterproof gloves should be worn during the radiolabeling procedure. The preparation of the product should be done by the following procedure.
- Required materials, not supplied:
- Indium In 111 Chloride from GE Healthcare, Inc. or Covidien, Inc.
- One sterile 1 mL syringe, one sterile 3 mL syringe
- Vial shield
- Dose calibrator set for Indium In 111
- Biodex Dark Green Chromatography strips
- Developing chamber for chromatography (e.g. scintillation vial)
- 21-23 gauge sterile needles
- Shield for 10 mL syringe
- Waterproof gloves
- Alcohol wipe
- Water-soluble marker
- 0.9% sodium chloride solution
- 0.05 M solution of diethylenetriamine pentaacetic acid (DTPA)
- Gamma ray detector
- Sterile, pyrogen-free Indium In 111 Chloride solution must be utilized in the preparation of the Indium In 111 ProstaScint®. The use of high purity Indium In 111 Chloride manufactured by GE Healthcare, Inc. or by Covidien, Inc. is required. The Indium In 111 Chloride should be used only to radiolabel ProstaScint® and should not be injected directly into the patient. The Indium In 111 Chloride should not be utilized after its expiration date.
- Before radiolabeling, bring the refrigerated ProstaScint®to room temperature. Note: ProstaScint® is a protein solution which may develop translucent particulates. These particulates will be removed by filtration.
- Clean the rubber stopper of each vial with an alcohol wipe. With a sterile 1 mL syringe add 0.1 mL of sodium acetate solution to the shielded vial of Indium In 111 chloride and mix. Retain remaining sodium acetate for use in Step 7.
- With the same 1 mL syringe, withdraw between 6 and 7 mCi of the buffered Indium In 111 chloride and add to the ProstaScint® vial. Flush the syringe to mix the preparation. Swirl gently to mix, and assay contents in a dose calibrator. On one of the labels provided, record the patient's identification, the date, time of preparation, and activity in the vial. Affix the label to the vial shield.
- Allow the labeling reaction to proceed at room temperature for 30 minutes.
- With a 3 mL syringe, add the remaining sodium acetate to the ProstaScint® reaction vial. To normalize pressure, withdraw an equal volume of air.
- Aseptically attach the 0.22 μm Millex® GV sterile filter (provided) and a sterile hypodermic needle to a 10 mL sterile disposable syringe and withdraw the contents of the reaction vial through the filter into the syringe. Keep the needle immersed in the solution to avoid creating an air-lock in the filter.
- Remove the filter and needle. Aseptically attach a fresh sterile hypodermic needle to the syringe. Assay syringe and contents in a dose calibrator. The syringe should contain not less than 4 mCi (148 MBq) of Indium In 111 ProstaScint®.
- Radiochemical purity (RCP) by Instant Thin Layer
Chromatography (ITLC) can be determined by the following procedure:
- Mix equal parts (several drops of each) of Indium In 111 ProstaScint® (capromab pendetide) with DTPA solution. Allow the mixture to stand at room temperature for one minute. Spot a small drop of the mixture onto an ITLC strip at its origin.
- Add 0.9% sodium chloride solution to the developing chamber to a depth of about 0.5 cm. Place the strip in a chromatography chamber with the origin at the bottom (ensure the strip does not bend or touch the walls of the chamber) and allow the solvent to migrate to about 0.5 cm from the end of the strip. A small dot made with a felt tip pen at this distance can help indicate the arrival of the solvent front. Remove from the chamber and cut the strip in half and measure the counts per minute (CPM) of both halves with a gamma ray detector.
- Calculate the percent RCP as follows:
- If the radiochemical purity is < 90%, the ITLC procedure should be repeated. If repeat testing remains < 90%, the preparation should not be administered.
%RCP = CPM bottom half x 100 CPM bottom half + CPM top half
- On the second label provided in the kit, record the patient's identification, the date, time of assay, and activity in the syringe. Affix this label to the syringe shield.
- Indium In 111 ProstaScint® should be used within 8 hours of radiolabeling.
- Discard vials, needles, and syringes in accordance with local, state, and federal regulations governing radioactive and biohazardous waste.
Image Acquisition and Interpretation
Images should be acquired using a large field of view gamma camera equipped with a parallel hole medium energy collimator. The gamma camera should be calibrated using the 172 and 247 keV photopeaks for Indium In 111 with a 15-20% symmetric window.
Whole body or spot planar views of the pelvis, abdomen, and thorax should be performed between 72 and 120 hours following Indium In 111 ProstaScint® (capromab pendetide) infusion. A cathartic is required the evening before imaging and a cleansing enema should be administered within an hour prior to each 72-120 hour imaging session. In addition, the bladder should be catheterized and irrigated.
Whole body acquisition should be carried out from skull through mid-femur. The total scan time over this area should be no less than 35 minutes using a 128x512 or 256x1024 matrix.
Planar images should be acquired in anterior and posterior views for 7.5 minutes per view using a 128x128 or 256x256 matrix. Due to uptake of Indium In 111 ProstaScint® by the liver, planar images obtained with the liver in the field of view must be acquired with adequate counts to allow the detection of lesions in the adjacent extrahepatic abdomen and pelvis. This may result in pixel overflow with image degradation in the region of the liver.
Two SPECT imaging sessions are necessary. The first SPECT session should be of the pelvis and be performed approximately 30 minutes after infusion to obtain a blood pool image. The second SPECT session should include both the pelvis and abdomen, including the lower liver margin through the prostatic fossa and be performed between 72 and 120 hours after infusion for detection of benign and malignant prostate tissue sites. Depending upon the capability of the camera field of view to include both pelvis and abdomen, either one or two separate acquisitions may be necessary during the second session.
To resolve imaging ambiguities possibly resulting from activity in blood pool, stool or urinary bladder, follow-up imaging sessions with full patient preparation should be performed.
The SPECT Images should be acquired using a 64x64 or 128x128 matrix for a minimum of 60 or 120 stops, respectively, over 360 degrees rotation for approximately 25 seconds per view at the first session and 50 seconds per view at the second session. Reconstruction should be performed using a Butterworth filter or equivalent in the transverse, coronal and sagittal views. An order of 5 and cut off of 0.5 may be used as a starting point. Slice thickness should be in the range of 6 to 12 mm.
It has been reported that Indium In 111 labeled antibodies may localize non-specifically in colostomy sites, degenerative joint disease, abdominal aneurysms, postoperative bowel adhesions, and local inflammatory lesions, including those typically associated with inflammatory bowel disease or secondary to surgery or radiation. Indium In 111 ProstaScint® can demonstrate apparent localization to sites of tortuous blood vessels. Careful review of the patient's medical history and other diagnostic information should aid in the interpretation of the images.
The diagnostic images acquired with Indium In 111 ProstaScint® should be interpreted in conjunction with other appropriate diagnostic tests.
The ProstaScint® (capromab pendetide) kit (NDC No. 57902-817-01) for the preparation of Indium In 111 labeled Capromab Pendetide includes one vial containing 0.5 mg of ProstaScint® per 1 mL of sodium phosphate buffered saline and one 2 mL vial of sodium acetate solution, 0.5 M. These solutions are sterile and pyrogen free and contain no preservatives. Each kit also includes one sterile 0.22 μm Millex® GV filter, prescribing information, and two identification labels.
Store at 2° to 8°C (36° to 46°F). Do not freeze. Store upright.
EUSA Pharma (USA) Customer Service: (800) 833-3533
Last reviewed on RxList: 7/9/2012
This monograph has been modified to include the generic and brand name in many instances.
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