Clarity granted US FDA Fast Track Designation for Cu-67 SAR-bisPSMA in treating metastatic castration-resistant prostate cancer.
Thursday, February 20, 2025
Clarity Pharmaceuticals a clinical-stage radiopharmaceutical company focused on developing advanced treatments for cancer, has received Fast Track Designation (FTD) from the United States Food and Drug Administration (FDA) for 67Cu-SAR-bisPSMA. This designation applies to the treatment of adults with prostate-specific membrane antigen (PSMA)-positive metastatic castration-resistant prostate cancer (mCRPC) who have previously undergone androgen receptor pathway inhibition (ARPI).
This follows two earlier FTDs granted for 64Cu-SAR-bisPSMA, aimed at diagnosing prostate cancer in patients with suspected metastasis and those experiencing biochemical recurrence after treatment. Two Phase III registration trials, CLARIFY and AMPLIFY, are currently in progress. The latest FTD highlights the potential of 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA in addressing significant gaps in prostate cancer treatment. The designations will enable Clarity to advance its SAR-bisPSMA programme, which spans the entire disease spectrum, from initial diagnosis to advanced stages.
FTD is designed to speed up the development and regulatory review of new therapies for serious conditions with limited treatment options. For SAR-bisPSMA, this designation facilitates a faster approval process, more frequent engagement with the FDA, and the option to submit completed sections of regulatory applications as they become available. These benefits are expected to accelerate the introduction of 67Cu-SAR-bisPSMA to the market for prostate cancer imaging and treatment.
The FTD submission was supported by preliminary data from the Phase I/IIa SECuRE study, which is assessing the safety and effectiveness of 67Cu-SAR-bisPSMA for mCRPC treatment. The dose escalation phase of the trial has been completed for three cohorts, with no reported dose-limiting toxicities. Most adverse events were mild, with dry mouth being the most common. Despite the advanced disease stage of participants, 73% showed PSA level reductions across all dose groups, including those receiving the lowest dose. Significant PSA reductions, including decreases of more than 50%, were observed in nearly half of the participants.
The trial is now in its final dose escalation phase, where participants receive multiple doses of 12 GBq of 67Cu-SAR-bisPSMA. Recruitment for this phase has been completed, and the final participants are in the follow-up period. A safety review meeting is planned for March 2025. One participant has so far shown a 98% PSA decline, along with a notable reduction in tumour volume.
Clarity has worked with international medical experts in prostate cancer to refine its treatment approach. A recent protocol amendment to the SECuRE trial aligns with findings from other studies, suggesting that targeting both androgen signalling and PSMA receptors could enhance treatment outcomes. The amendment expands the cohort from 14 to 24 patients and includes combination therapy with enzalutamide. Several trial sites have approved these changes, which could further improve results.
This approach prioritises commercialisation in the largest market segment for prostate cancer therapy, with pre-chemotherapy cases being significantly higher than post-chemotherapy cases. The 64Cu/67Cu platform is uniquely suited to address challenges in radiopharmaceutical supply, offering a streamlined solution for treating a broad range of patients.
SAR-bisPSMA uses a novel method of linking two PSMA-targeting agents to Clarity's proprietary sarcophagine (SAR) technology. This ensures that copper isotopes remain securely contained within a chelator, preventing leakage into the body. It functions as a Targeted Copper Theranostic (TCT), combining copper-64 (64Cu) for imaging with copper-67 (67Cu) for therapy.
Currently, 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA are unregistered treatments. Their safety and efficacy have not yet been confirmed by regulatory authorities such as the FDA or the Therapeutic Goods Administration (TGA), and commercial availability is not guaranteed.
The SECuRE trial is a multi-centre, single-arm study designed to assess the safety, tolerability, and effectiveness of 64Cu-SAR-bisPSMA and 67Cu-SAR-bisPSMA. The recent protocol amendment has expanded the study and introduced combination therapy with enzalutamide for selected participants.
Prostate cancer is the second most commonly diagnosed cancer in men worldwide and a leading cause of cancer-related deaths. The American Cancer Institute projects approximately 313,780 new cases of prostate cancer in the United States in 2025, with around 35,770 expected deaths from the disease.
Source: prnewswire.com
