Clarity Pharmaceuticals (ASX:CU6) said a participant with metastatic castration-resistant prostate cancer in the phase 2 group expansion phase of the SECuRE trial achieved undetectable disease as assessed by prostate-specific antigen and prostate-specific membrane antigen positron emission tomography, according to a Monday Australian bourse filing.

The trial is evaluating the safety and efficacy of the company's targeted copper therapy-diagnostic product, copper-67-SAR-bisPSMA, for the potential treatment of prostate cancer.

The participant achieved undetectable prostate-specific antigen levels seven weeks after his first cycle of copper-67-SAR-bisPSMA, the filing said. No disease was observed on prostate-specific membrane antigen positron emission tomography after receiving one more cycle of copper-67-SAR-bisPSMA. The participant showed mild related adverse effects, including altered taste, dry eyes, eye pain, fatigue, and salivary gland soreness. No blood-related or renal adverse effects were observed.

This is the fifth patient to achieve undetectable disease by radiographic assessment following copper-67-SAR-bisPSMA treatment, per the filing. The company aims to complete participant recruitment for the group expansion phase this year.

Clarity Pharmaceuticals' shares rose nearly 9% in recent trading on Monday.