# A single-molecule copper-64/copper-67 pair instead of switching ligands between scan and treatment

Source: https://nuclide.cc/ideas/idea-copper-theranostic-pair-standard/  
Nuclide record `idea-copper-theranostic-pair-standard` (Idea). Data CC BY-NC 4.0, attribute "Data from Nuclide (nuclide.cc)"; commercial use needs a licence.

## TL;DR

Most PSMA treatments use one molecule to take the pre-treatment scan and a slightly different molecule for the actual treatment, so the scan is only an approximate guide. A copper-based pair uses the identical molecule for both steps, just with a different form of copper, so the scan should be a much truer preview of where the treatment radiation will go.

## Summary

The standard PSMA theranostic workflow images patients with 68Ga-PSMA-11 or a related diagnostic ligand and then treats responders with 177Lu-PSMA-617, a chemically different molecule; differences in the two ligands' binding and pharmacokinetics mean the diagnostic scan is only an approximate predictor of the therapeutic biodistribution. Clarity Pharmaceuticals' SAR-bisPSMA programme instead uses one identical molecule labelled with two isotopes of the same element: copper-64 for PET imaging and copper-67 for beta-emitting therapy, so in principle the diagnostic scan should be a much closer match to the therapeutic distribution than a cross-ligand, cross-element approach.

The combination is being tested in the ongoing SECuRE trial (NCT04868604), a US multi-centre, single-arm phase I/IIa study in metastatic castration-resistant prostate cancer, aiming to enrol approximately 54 participants. Company-reported interim results (data cut-off 20 July 2026) from 19 participants treated at the 8 GBq 67Cu-SAR-bisPSMA dose level showed a PSA50 response rate of 63% and PSA90 of 26%, with 81% of radiographically evaluable participants achieving disease control, including 31% with a complete response or undetectable disease by RECIST, bone scan or PSA; no dose-limiting toxicities have been reported across dose-escalation cohorts up to 12 GBq, and the sponsor states registrational phase 3 planning is under way.

These results come from company press releases and conference-style updates rather than an independent peer-reviewed publication, and the trial is a single-arm study, so there is no direct comparison yet against 177Lu-PSMA-617 or another PSMA radioligand therapy to establish whether the same-molecule imaging/therapy matching translates into a measurable clinical advantage over the established gallium-68/lutetium-177 approach.

## Fields

- Kind: Idea
- Last checked: 2026-09-22
- Tags: copper theranostics; prostate; same-molecule imaging
- Hypothesis: Using the identical molecule for imaging (copper-64) and therapy (copper-67) in PSMA-targeted treatment, rather than switching between different ligands such as gallium-68-PSMA-11 for imaging and lutetium-177-PSMA-617 for therapy, will give a more accurate match between the pre-therapy scan and the actual therapeutic radiation distribution, improving patient selection and predicting toxicity more reliably.
- Rationale: Because 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA are the same molecule differing only in the copper isotope, the pre-therapy scan should in principle predict the therapeutic biodistribution more directly than the common practice of imaging with one ligand and treating with a different one. Interim company-reported results from the SECuRE trial (19 participants at the 8 GBq dose level) show promising PSA response and radiographic disease-control rates with no observed dose-limiting toxicity, but these are sponsor-reported interim data from a single-arm trial, not an independent peer-reviewed head-to-head comparison against 177Lu-PSMA-617.
- Proposed test: The ongoing SECuRE trial itself (NCT04868604, approximately 54 planned participants) reporting mature, independently peer-reviewed phase II data, followed by a randomised phase 3 (registrational planning reported by the sponsor as under way) comparing 67Cu-SAR-bisPSMA against 177Lu-PSMA-617 or standard of care in metastatic castration-resistant prostate cancer.
- Maturity: early-clinical
- Actor: industry

## Sources

- SECuRE update: 8 GBq Cu-67 SAR-bisPSMA dose level results (Clarity Pharmaceuticals, Aug 2026): https://www.claritypharmaceuticals.com/news/secure-update-05-08-26/
- SECuRE trial update: another participant with undetectable disease (Clarity Pharmaceuticals, Feb 2026): https://www.claritypharmaceuticals.com/news/secure-undetectable/
- 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA (SECuRE) (ClinicalTrials.gov, NCT04868604): https://clinicaltrials.gov/study/NCT04868604

## Connected records

- trials: [64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA for Identification and Treatment of PSMA-expressing Metastatic Castrate Resistant Prostate Cancer (SECuRE)](https://nuclide.cc/trials/nct04868604/)
- targets: [PSMA](https://nuclide.cc/targets/psma/)
- indications: [Metastatic castration-resistant prostate cancer](https://nuclide.cc/indications/prostate-mcrpc/)
- drugs: [Lutetium-177 vipivotide tetraxetan](https://nuclide.cc/drugs/pluvicto/)
- isotopes: [Copper-64](https://nuclide.cc/isotopes/cu-64/), [Copper-67](https://nuclide.cc/isotopes/cu-67/), [Gallium-68](https://nuclide.cc/isotopes/ga-68/), [Lutetium-177](https://nuclide.cc/isotopes/lu-177/)

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