Technetium Tc-99m maraciclatide

Summary

Technetium-99m maraciclatide (also called 99mTc‑maraciclatide or NC100692) is an investigational radiopharmaceutical that binds the αvβ3 integrin. It is used experimentally for gamma‑camera imaging to visualise integrin expression in inflamed joints of rheumatoid arthritis and in bone metastases of prostate cancer, providing a whole‑body snapshot of disease activity.

Mechanism of Action

Maraciclatide is a cyclic RGD peptide that selectively binds the αvβ3 integrin, a cell‑adhesion receptor up‑regulated on activated endothelial cells, osteoclasts, and certain tumour cells. When labelled with the gamma‑emitting isotope Tc‑99m, the peptide concentrates in tissues expressing the integrin, allowing detection by planar or SPECT imaging. The signal intensity reflects the density of αvβ3 integrin, which correlates with inflammation or osteoclast‑mediated bone turnover.

What the Research Shows

Two peer‑reviewed studies have explored Tc‑99m maraciclatide imaging. In a cohort of 48 rheumatoid arthritis patients, hand and wrist scans demonstrated integrin‑targeted uptake that correlated with power‑Doppler ultrasound findings; machine‑learning segmentation (nnU‑Net) successfully distinguished normal, low, and highly inflamed tissue. In a separate group of 17 men with prostate‑cancer bone metastases, the tracer accumulated in lesions with high αvβ3 expression, especially those with lower CT density, suggesting a link to osteoclast activity. Serial imaging before and 12 weeks after abiraterone therapy showed divergent changes in tumour‑to‑muscle ratios between patients with progressive disease and those without, indicating potential for early response assessment. Both investigations were small, proof‑of‑concept studies using standard gamma‑camera or SPECT/CT techniques.

Reported Benefits

Tc‑99m maraciclatide offers a non‑invasive method to visualise integrin‑mediated pathology across the entire skeleton or joints in a single scan, potentially complementing ultrasound and MRI. In rheumatoid arthritis, it may identify inflamed sites not captured by conventional imaging. In oncology, it can highlight metabolically active bone metastases and provide an early biomarker of therapeutic response, which could guide treatment decisions before anatomical changes become apparent.

Limitations of the Evidence

Evidence is limited to small, single‑centre studies; larger, multicentre trials are needed to confirm diagnostic accuracy and reproducibility. The rheumatoid arthritis work focused on image‑analysis algorithms rather than clinical outcomes, and the prostate‑cancer study involved only 17 participants with variable follow‑up. Uptake may differ according to lesion composition (sclerotic vs lytic), and the tracer is not yet approved for routine clinical use. Artificial‑intelligence segmentation, while promising, requires further validation before integration into practice.

Safety Considerations

As a Tc‑99m labelled peptide, maraciclatide carries the typical radiation dose associated with diagnostic nuclear‑medicine scans, which is generally low but must be justified. No adverse events were reported in the cited studies, and Tc‑99m agents are usually well tolerated. Nonetheless, standard precautions apply: avoid use in pregnant or breastfeeding individuals unless benefits outweigh risks, and monitor for rare allergic reactions to the peptide component.

How It Is Administered

The compound is administered intravenously as a Tc‑99m‑labeled solution. Imaging is performed with gamma‑camera planar or SPECT/CT systems at predefined time points after injection, usually within a few hours to capture optimal integrin‑specific uptake. No specific dosing regimen is provided in the literature; protocols follow standard nuclear‑medicine practices for Tc‑99m radiopharmaceuticals.

Routes of Administration

Goals & Uses

• Lung cancer imagingDiagnostic OncologyLow
• Breast cancer lesion detectionDiagnostic OncologyModerate
• Assessment of anti-angiogenic therapy responseTheranostic MonitoringLow
• Cardiovascular disease assessmentDiagnosticLow
• Atherosclerotic plaque imagingCardiovascular DiagnosticsLow
• Imaging tumor angiogenesisDiagnostic OncologyModerate
• Tumor angiogenesis imagingDiagnosticModerate

Contraindications

• Severe renal impairmentOrganModerateKidney function concerns
• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• Severe allergy to technetium or peptide componentsAllergicModerate
• Known hypersensitivity to RGD peptides or excipientsAllergyHigh
• BreastfeedingPopulationModeratePotential transfer into breast milk or insufficient safety data

Adverse Effects

• Radiation exposureRadiologicalUnknown
• Allergic reactionImmunologicRareImmune-mediated hypersensitivity response
• Injection site reactionsLocalUncommon
• Injection site painLocalCommonPain at the injection site
• Hypersensitivity/allergic reactionsImmunologicRare
• NauseaGastrointestinalUncommonFeeling of sickness or urge to vomit

Drug Interactions

• Other Tc-99m radiopharmaceuticalsModerate
• Anti-angiogenic agents (e.g., bevacizumab, sunitinib)Moderate
• Other radiopharmaceuticalsModerate

Population Constraints

• Pediatric patientsAgeRelative
• Breastfeeding womenReproductiveRelative
• Pregnant womenReproductiveAbsolute
• Patients with severe renal impairmentOrgan ImpairmentRelative

Regulatory Status

• European UnionUnapprovedNot authorized for clinical use
• United StatesInvestigationalInvestigational New Drug (IND) studies only
• United KingdomInvestigationalEvaluated in UK clinical trials including breast cancer SPECT studies; not approved for routine clinical use.

Investigated under IND/CTA in multiple jurisdictions. Phase II clinical trials conducted. Not currently FDA-approved or EMA-approved for routine clinical use as of the knowledge cutoff. Classified as an investigational radiopharmaceutical.

Evidence & Sources

• Deep Learned Segmentations of Inflammation for Novel ⁹⁹(m)Tc-maraciclatide Imaging of Rheumatoid Arthritis
  Journal ArticleLowCobb R, Cook GJR, Reader AJ2023-01-01T00:00:00.000000Z
• Imaging α(v)β(3) integrin expression in skeletal metastases with (99m)Tc-maraciclatide single-photon emission computed tomography: detection and therapy response assessment
  Journal ArticleLowCook GJR, et al.2018-01-01T00:00:00.000000Z

Frequently Asked Questions