Neuraceq (Florbetaben F18)

What Is Neuraceq and What Is It Used For?

Neuraceq belongs to a class of medications known as radiopharmaceutical diagnostic agents. Its active substance, florbetaben labeled with the radioactive isotope fluorine-18, is specifically designed to cross the blood-brain barrier after intravenous injection and bind selectively to beta-amyloid neuritic plaques. These plaques are protein deposits that accumulate in the brain tissue and are one of the hallmark pathological features of Alzheimer's disease.

Once florbetaben (18F) binds to amyloid plaques, the fluorine-18 isotope emits positrons that are detected by a PET scanner. This produces detailed images showing the distribution and density of amyloid plaques throughout the brain. The imaging results are interpreted by physicians trained in nuclear medicine or neuroradiology who use a standardized visual assessment method to classify the scan as either positive (indicating moderate to frequent amyloid plaques) or negative (indicating sparse to no plaques).

It is important to understand that Neuraceq is an adjunct diagnostic tool, not a standalone test. A positive scan is consistent with, but does not by itself establish, a diagnosis of Alzheimer's disease or any other cognitive disorder. Beta-amyloid plaques can be present in cognitively normal older adults as well as in patients with other neurological conditions such as Lewy body dementia. Conversely, a negative Neuraceq scan reduces the likelihood that the patient's cognitive impairment is due to Alzheimer's disease, since Alzheimer's pathology typically involves significant amyloid deposition.

Neuraceq was initially developed by Piramal Imaging (now Life Molecular Imaging) and received marketing authorization from the European Medicines Agency (EMA) in 2014 and approval from the U.S. Food and Drug Administration (FDA) in March 2014. It is one of several approved amyloid PET tracers available internationally, alongside florbetapir (Amyvid) and flutemetamol (Vizamyl). These tracers have become increasingly valuable in clinical practice, particularly with the advent of anti-amyloid therapies such as lecanemab and donanemab, where confirming the presence of amyloid pathology is a prerequisite for treatment initiation.

What Should You Know Before Receiving Neuraceq?

Before undergoing a Neuraceq PET scan, it is essential that your healthcare team has a comprehensive understanding of your medical history, current medications, and overall health status. While Neuraceq is generally well-tolerated and the procedure is minimally invasive, there are important considerations that must be evaluated before administration.

Contraindications

There are no absolute contraindications listed for Neuraceq beyond known hypersensitivity to the active substance (florbetaben) or any of its excipients. However, the procedure involves intravenous injection and radiation exposure, which necessitate careful patient evaluation. Patients with a history of severe allergic reactions to radiopharmaceuticals should inform their physician prior to the procedure.

Warnings and Precautions

Several important precautions should be considered before and during the administration of Neuraceq:

• Image interpretation errors: False-positive and false-negative results can occur. Neuraceq PET images should be interpreted only by readers who have completed special training in the interpretation of amyloid PET images. Errors in image interpretation can lead to inappropriate patient management.
• Radiation exposure: As with all radioactive medicinal products, Neuraceq contributes to the patient's cumulative long-term radiation exposure. The effective dose from a single 300 MBq injection is approximately 5.8 mSv, which is comparable to other nuclear medicine procedures. The radiation exposure should be justified by the expected diagnostic benefit.
• Limitations of amyloid imaging: A positive scan does not establish a clinical diagnosis. Amyloid deposits can be found in cognitively normal elderly individuals. A negative scan does not exclude all neurological disorders or other causes of cognitive impairment.
• Hydration: Patients should be adequately hydrated before and after the procedure to facilitate urinary excretion of the radiotracer and minimize radiation dose to the bladder.
• Voiding: Frequent voiding is recommended after the procedure to reduce radiation exposure to the urinary bladder.

Pregnancy and Breastfeeding

Neuraceq is contraindicated in pregnancy. The procedure involves exposure to ionizing radiation, which poses risks to the developing fetus. Women of childbearing potential must have a negative pregnancy test before the procedure. If a Neuraceq scan is considered medically necessary during breastfeeding, the European Medicines Agency recommends interrupting breastfeeding for at least 24 hours after injection, during which expressed milk should be discarded. This precaution ensures that the infant is not exposed to radioactivity through breast milk.

Special Populations

No dose adjustment is required for elderly patients, who represent the primary population undergoing amyloid PET imaging. The safety and efficacy of Neuraceq have not been established in patients under 18 years of age, as beta-amyloid imaging is not indicated in pediatric populations. Patients with significant renal or hepatic impairment should be evaluated on a case-by-case basis, as these conditions may affect the pharmacokinetics and clearance of the radiotracer.

How Does Neuraceq Interact with Other Drugs?

Because Neuraceq is administered as a single dose for diagnostic purposes and is rapidly cleared from the body, the potential for clinically significant drug interactions is considered low. The radioactive fluorine-18 isotope has a short half-life of approximately 110 minutes, and the total mass of florbetaben injected is very small (typically less than 20 micrograms). No formal drug-drug interaction studies have been published for Neuraceq.

Nevertheless, certain medications and substances warrant consideration in the context of amyloid PET imaging. Patients should provide their healthcare team with a complete list of all prescription medications, over-the-counter drugs, herbal supplements, and dietary supplements they are currently taking.

Potential Considerations

It is worth noting that the binding characteristics of florbetaben (18F) are highly specific to fibrillar beta-amyloid. Currently available evidence does not suggest that commonly prescribed medications for neurological or psychiatric conditions interfere with the binding of florbetaben to amyloid plaques. However, ongoing treatment with anti-amyloid monoclonal antibodies may reduce plaque density over time, which could affect interpretation of follow-up scans.

What Is the Correct Dosage of Neuraceq?

Neuraceq is administered exclusively by healthcare professionals trained in the use of radiopharmaceuticals. The dosing is standardized and does not vary based on body weight or body surface area, which distinguishes it from many other injectable medications. The preparation and quality control of the radiotracer must follow strict radiopharmacy protocols before administration.

Adults

Children

Neuraceq is not indicated for use in pediatric patients (under 18 years of age). Beta-amyloid neuritic plaques associated with Alzheimer's disease do not occur in children, making amyloid PET imaging clinically irrelevant in this population. No dosing information is available for pediatric use.

Elderly

No dose adjustment is required for elderly patients. The vast majority of clinical experience with Neuraceq has been in patients aged 55 years and older, and the recommended dose of 300 MBq applies equally regardless of the patient's age. Elderly patients may have reduced renal function, which could slightly delay clearance of the radiotracer, but this does not affect image quality or the diagnostic accuracy of the scan. Adequate hydration and frequent voiding remain important to minimize radiation exposure.

Missed Dose

The concept of a missed dose does not apply to Neuraceq in the traditional sense, as it is administered as a single diagnostic dose in a clinical setting. If the scan cannot be completed within the recommended 45–130-minute window after injection, a new appointment may need to be scheduled with a fresh preparation of the radiotracer, since the fluorine-18 isotope decays rapidly (half-life ~110 minutes).

Overdose

Overdose with Neuraceq is unlikely given that it is administered in a controlled clinical environment by trained personnel. In the event that a higher-than-intended activity is administered, the primary concern is increased radiation exposure. Management would include promoting hydration and frequent urination to accelerate renal excretion of the radiotracer. There is no specific antidote. The estimated effective radiation dose is approximately 19.3 μSv per MBq, meaning that even moderate overdoses would result in radiation exposures within the range seen in other common nuclear medicine procedures.

What Are the Side Effects of Neuraceq?

The safety profile of Neuraceq has been evaluated in clinical studies involving more than 2,400 subjects. Overall, the frequency and severity of adverse reactions were low. Most reported side effects were mild, transient, and resolved without specific treatment. The most commonly observed adverse events were related to the injection site or were systemic effects associated with the intravenous administration procedure itself.

Below is a summary of reported side effects organized by frequency according to the standard MedDRA classification (Medical Dictionary for Regulatory Activities):

Radiation-Related Risks

As with all radiopharmaceutical procedures, administration of Neuraceq involves exposure to ionizing radiation. The effective dose from a standard 300 MBq injection is approximately 5.8 mSv. For context, this is comparable to the radiation exposure from a standard CT scan of the chest and less than the annual background radiation dose in many parts of the world (approximately 2.4 mSv per year globally). The organs receiving the highest absorbed doses are the gallbladder wall, upper large intestine, small intestine, and urinary bladder wall.

The risk of radiation-induced cancer from a single Neuraceq scan is considered very low. However, cumulative radiation exposure should be considered, particularly in patients who may undergo multiple nuclear medicine procedures. The principle of ALARA (As Low As Reasonably Achievable) should always be applied when considering radiodiagnostic procedures.

When to Seek Medical Attention

While serious adverse reactions to Neuraceq are rare, patients should seek immediate medical attention if they experience signs of a severe allergic reaction, including difficulty breathing, swelling of the face or throat, severe skin rash, or rapid heartbeat. The imaging facility should be equipped with appropriate emergency medication and monitoring equipment to manage hypersensitivity reactions.

How Should Neuraceq Be Stored?

Neuraceq is a radioactive medicinal product that requires specialized storage and handling procedures. Patients will never need to store this product at home, as it is prepared and administered exclusively in authorized nuclear medicine facilities. However, understanding the storage requirements provides insight into the nature of this diagnostic agent.

The product must be stored at a temperature not exceeding 25°C (77°F) in its original lead-shielded container. It should not be frozen. Due to the radioactive decay of fluorine-18, which has a half-life of approximately 109.77 minutes, Neuraceq has a limited shelf life and must be used within 10 hours of the end of synthesis (EOS). The activity at the time of injection must be verified using a calibrated dose calibrator.

Storage and disposal of Neuraceq must comply with national and local regulations governing radioactive materials. Unused product or waste material must be disposed of through approved radioactive waste management procedures. Healthcare facilities are required to maintain detailed records of the receipt, storage, use, and disposal of all radioactive pharmaceuticals.

As with all medicines, Neuraceq must be kept out of the reach and sight of unauthorized persons. The product should be visually inspected before use; it should be a clear, colorless to slightly yellow solution. Do not use the product if it appears cloudy, contains particulate matter, or if the container appears damaged.

What Does Neuraceq Contain?

The active substance in Neuraceq is florbetaben (18F), a stilbene derivative labeled with the positron-emitting radionuclide fluorine-18. The chemical name is 4-[(E)-2-(4-{2-[2-(2-fluoroethoxy)ethoxy]ethoxy}phenyl)vinyl]-N-methylaniline. Each milliliter of solution contains 300 MBq of florbetaben (18F) at the date and time of calibration.

The following inactive ingredients (excipients) serve important roles in the formulation:

• Ascorbic acid: Acts as an antioxidant to prevent radiolysis (radiation-induced degradation) of the active substance, maintaining the radiochemical purity of the product throughout its shelf life.
• Sodium ascorbate: Serves as a pH buffer and additional antioxidant, working in conjunction with ascorbic acid to stabilize the formulation.
• Ethanol: Present in small quantities as a co-solvent to maintain the solubility of florbetaben. The maximum ethanol content per dose is approximately 10% by volume.
• Macrogol 400 (PEG 400): A polyethylene glycol derivative used as a co-solvent to enhance the stability and solubility of the active substance.
• Water for injections: The primary solvent, meeting pharmacopeial standards for sterile injectable preparations.

Neuraceq does not contain any preservatives, dyes, or sugars. The solution has a pH range of approximately 4.5 to 7.0. Each vial contains a single dose intended for one patient only. Any unused portion must be discarded in accordance with radioactive waste disposal regulations.