Pendetide

Summary

Pendetide is a DTPA-based chelating peptide used as a linker in the radiopharmaceutical capromab pendetide (ProstaScint). When labeled with indium-111, it enables scintigraphic imaging of prostate cancer. The compound is a conjugate of the 7E11-C5 murine monoclonal antibody fragment (capromab) with GYK-DTPA (pendetide), targeting PSMA for detection of metastatic prostate cancer.

Mechanism of Action

Pendetide is a diethylenetriaminepentaacetic acid (DTPA)-based chelating peptide conjugated to a targeting antibody fragment. It chelates radioactive metals (e.g., indium-111) via the DTPA moiety, enabling radiolabeling of antibody fragments for diagnostic imaging. When conjugated to capromab (anti-PSMA antibody fragment), the complex localizes to prostate-specific membrane antigen (PSMA)-expressing prostate cancer cells.

Routes of Administration

Goals & Uses

• Monitoring biochemical recurrenceOncology / SurveillanceLow
• Detection of prostate cancer metastasesDiagnostic ImagingModerate
• Staging of prostate cancerOncology / StagingModerate

Contraindications

• PregnancyPopulationHighPotential fetal risk or insufficient safety data
• BreastfeedingPopulationHighPotential transfer into breast milk or insufficient safety data
• Hypersensitivity to murine antibodiesImmunologicHigh

Adverse Effects

• Radiation exposureRadiologicalCommon
• Hypersensitivity / allergic reactionsImmunologicUncommon
• Injection site reactionsLocalUncommon
• HAMA developmentImmunologicUncommon

Drug Interactions

• ImmunosuppressantsLowPotential interaction with immune pathways or infection risk
• Other radiopharmaceuticalsModerate

Population Constraints

• Pediatric patientsAgeRelative
• Prior murine antibody exposureImmunologic HistoryRelative
• Patients with renal impairmentOrgan ImpairmentRelative

Regulatory Status

• European UnionUnknownLimited regulatory approval history in Europe; largely superseded by PSMA PET imaging agents
• United StatesWithdrawnApproved: Detection of intra-pelvic metastases and recurrent prostate cancer (PSMA imaging)FDA-approved in 1996 as capromab pendetide (ProstaScint); voluntarily withdrawn from market circa 2017–2018 for commercial reasons, not due to safety issues

Capromab pendetide (ProstaScint) was FDA-approved in 1996 for imaging of prostate cancer. The product was withdrawn from the US market by Aytu BioScience around 2017–2018 for commercial reasons, not safety concerns.

Evidence & Sources

No sources recorded yet.