Trial of novel copper-based PSMA theranostics for mCRPC hits early enrollment goal

The phase 1/2a SECURE trial exploring 2 novel SAR-bisPSMA Targeted Copper Theranostics (TCT) in patients with metastatic castration-resistant prostate cancer (mCRPC) has completed recruitment for the initial dosimetry phase, according to Clarity Pharmaceuticals, the company developing the investigational agents.¹

The open-label, single-arm, dose-escalation SECURE trial (NCT04868604) is specifically exploring the PSMA PET imaging product ⁶⁴Cu-SAR-bisPSMA and the PSMA targeted therapy ⁶⁷Cu-SAR-bisPSMA.² The basic design of the trial is that ⁶⁴Cu-SAR-bisPSMA will be used for the selection of appropriate patients to receive treatment with ⁶⁷Cu-SAR-bis-PSMA.

To enroll on the trial, patients must have mCRPC that has progressed despite being treated with androgen-deprivation therapy and at least 1 second-generation androgen receptor pathway inhibitor, such as abiraterone acetate (Zytiga) or enzalutamide (Xtandi). Patients are required to have an ECOG performance status of 0 to 2, and a castrate level of serum/plasma testosterone (<50 ng/dL or <1.7 nmol/L). Individuals with brain metastases are not eligible to enroll.

Across all phases of the study, the total enrollment goal is 44 patients. The study is being conducted at 7 locations in the United States.

“Our TCT platform uniquely uses the same chemical entity for both diagnosis and therapy, leading to high accuracy and high precision, and highlights the benefits of generating ⁶⁴Cu imaging data from 1h to 72h after administration to help determine the suitability of treatment with ⁶⁷Cu. We strongly believe SAR-bisPSMA will be an important pillar in the next generation of radiopharmaceuticals, with blockbuster potential both diagnostically and therapeutically. The central manufacture, logistical and treatment advantages of TCT associated with using the isotope pairing of ⁶⁴Cu and ⁶⁷Cu in large patient populations such as prostate cancer will provide significant benefits to both patients and clinicians in comparison to current products in the market,” Dr Alan Taylor, executive chairman of Clarity, stated in a news release.

Also commenting in the release, Dr. Luke Nordquist, CEO, Urologic Medical Oncologist at the Urology Cancer Center and GU Research Network in Omaha, Nebraska, who treated patients in the initial dosimetry phase of the trial, stated, “I am very impressed with the data from the initial dosimetry phase and we look forward to progressing the SECuRE trial into the therapy phase and further validating the benefits of the ⁶⁴Cu SAR-bisPSMA and ⁶⁷Cu SAR-bisPSMA products for both clinicians and patients. Current standard of care SPECT imaging agents don’t have the resolution of the new PET agents, however the new PET agents rely on radionuclides with very short half-lives such as ¹⁸F and ⁶⁸Ga, which limits their availability and utilization. Having access to centrally manufactured PET imaging products with a more suitable half-life, such as ⁶⁴Cu, will significantly improve patient care and address the current backlog of patients waiting for critical imaging scans. Importantly, the potential for improved prostate cancer diagnosis and treatment will have significant benefits for prostate cancer patients.”

References

1. Recruitment for the dosimetry phase of Clarity’s Cu-64/Cu67 SAR-bisPSMA theranostic prostate cancer trial completed. Published online November 10, 2021. Accessed November 10, 2021. https://prn.to/3D5b0DE.

2. NIH ClinicalTrials.gov. 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA for Identification and Treatment of PSMA-expressing Metastatic Castrate Resistant Prostate Cancer (SECURE). Last update May 3, 2021. Accessed May 5, 2021. https://clinicaltrials.gov/ct2/show/NCT04868604.