gallium Ga 68 dotatate (Rx)

Postmarketing Reports

Gastrointestinal disorders: Nausea and vomiting

General disorders and administration site conditions: Injection site pain and burning sensation

Contraindications

None

Cautions

Radiation risk

• Avoid close contact with infants and pregnant women during first 12 hours after administration of Ga 68 dotatate
• Contributes to a patient’s overall long-term cumulative radiation exposure; long-term cumulative radiation exposure associated with increased cancer risk
• Ensure safe handling and preparation procedures to protect patients and healthcare workers from unintentional radiation exposure

Risk for image misinterpretation

• Uptake of Ga 68 dotatate reflects somatostatin receptor density in NETs
• Uptake can also be seen in a variety of other tumor types (eg, those derived from neural crest tissue)
• Increased uptake might be seen in sites of splenosis or other pathologic conditions (eg, thyroid disease or subacute inflammation) or might occur as a normal physiologic variant (eg, uncinate process of the pancreas)
• PET images with Ga 68 dotatate should be interpreted visually and the uptake may need to be confirmed by histopathology or other assessments to confirm NET diagnosis
• A negative scan after administration of Ga 68 dotatate in patients who do not have history of NETs, including in patients suspected of ectopic ACTH-secreting tumors, does not rule out the presence of NETs

Drug interaction overview

• Nonradioactive somatostatin analogs competitively bind to the same somatostatin receptors as Ga 68 dotatate
• Image patients with Ga 68 dotatate PET just prior to dosing with long-acting analogs of somatostatin
• Short-acting analogs of somatostatin can be used up to 24 hr before imaging with Ga 68 dotatate
• Corticosteroids can down-regulate somatostatin subtype 2 receptors; repeated administration of high doses of glucocorticoid prior to Ga 68 dotatate administration may result in false negative imaging

Pregnancy

There are no studies in pregnant women to inform any drug-associated risks; however, all radiopharmaceuticals have the potential to cause fetal harm

Lactation

There is no information on the presence of Ga 68 dotatate in human milk, the effect on the breastfed infant, or the effect on milk production

Advise breastfeeding women to interrupt breastfeeding and pump and discard breast milk for 12 hr after administration to minimize radiation exposure to a breastfed infant

Pregnancy Categories

A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.

B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.

C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.

D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.

X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.

NA: Information not available.

Mechanism of Action

Ga 68 dotatate binds to somatostatin receptors with highest affinity for subtype 2 receptors (sstr2); dota-tate, also known as DOTA-0-Tyr3-Octreotate, is a cyclic 8 amino acid peptide with a covalently bound chelator (dota)

It binds to cells that express somatostatin receptors, including malignant cells, which overexpress sstr2 receptors

Gallium 68 (68Ga) is a beta-emitting radionuclide with an emission yield that allows positron-emission tomography (PET) imaging

Distribution

Distributes to all sstr2-expressing organs such as pituitary, thyroid, spleen, adrenals, kidney, pancreas, prostate, liver, and salivary glands

No uptake in the cerebral cortex or in the heart, and usually thymus and lung uptakes are low

Elimination

12% of the injected dose is excreted in urine in the first 4 hr postinjection

IV Preparation

See full prescribing information for drug preparation using a lead glass shield for radioprotection purposes

Drug handling

• After reconstitution and radiolabeling, handle injection with appropriate safety measures to minimize radiation exposure
• Use waterproof gloves, effective radiation shielding, and appropriate safety measures when preparing and handling Ga 68 dotatate injection
• Radiopharmaceuticals should be used by or under the control of physicians and nuclear pharmacists who are qualified by specific training and experience in the safe use and handling of radionuclides, and whose experience and training have been approved by the appropriate governmental agency authorized to license the use/preparation of radionuclides

Patient preparation

• Instruct patients to drink a sufficient amount of water to ensure adequate hydration prior to administration of Ga 68 dotatate

IV Administration

Verify injected radioactivity by measuring the radioactivity of vial with a dose calibrator before administration to the patient

Ensure that the injected radioactivity is within ±10% of the recommended dose

Inject as an IV bolus

Patients must drink and void frequently during the first hours following administration to reduce radiation exposure

Image acquisition

• For Ga 68 dotatate PET imaging, the acquisition must include a whole body acquisition from skull to mid thigh
• Images can be acquired 40-90 minutes after IV bolus
• Adapt imaging acquisition delay and duration according to the equipment used, and the patient and tumor characteristics, in order to obtain the best image quality possible

Storage

Radionuclide is not part of the kit

Before reconstitution and radiolabelling with Ga 68, contents of this kit are not radioactive

For prolonged storage, store kit in its original packaging at room temperature <25ºC

Do not freeze

After reconstitution and radiolabeling

• Keep injection upright with an appropriate shielding to protect from radiation, at a temperature <25ºC (do not freeze) for a maximum of 4 hr
• Storage of the radiolabelled product must comply with regulatory requirements for radioactive materials