Phase 1/2 Trials Begin for PSMA-R2 Compounds Being Tested for Prostate Cancer Treatment, Diagnostics

Phase 1/2 Trials Begin for PSMA-R2 Compounds Being Tested for Prostate Cancer Treatment, Diagnostics

Two Phase 1/2 clinical trials testing PSMA-R2-based treatment and diagnostic candidates for prostate cancer have begun dosing their first patients, Advanced Accelerator Applications (AAA) announced in a press release.

PSMA-R2 is a urea-based radioligand — a radioactive-labeled biochemical compound — of the protein prostate-specific membrane antigen (PSMA), which is frequently overproduced in prostate cancer cells. It is part of AAA’s theragnostic platform, a strategy that integrates diagnostics and therapeutics for cancer management.

“Advancing PSMA-R2 into clinical studies is a major milestone for AAA,” Germo Gericke, MD, head of research and development at AAA, said in the release. “We are eager to explore the full potential of this innovative platform in large patient populations, such as prostate cancer.”

The open-label, multicenter PROter trial (NCT03490838) is assessing 177Lu-PSMA-R2 for the treatment of patients with PSMA-positive, metastatic, castration-resistant prostate cancer, who received previous systemic treatment.

The study will assess the treatment’s safety, tolerability, and radiation dosimetry (the dosage absorbed by the body), while also further evaluating its effectiveness.

While the first part of the trial will establish the recommended dose of 177Lu-PSMA-R2, the second part will mainly assess preliminary anti-tumor response of repeated treatments and determine the treatment’s safety and patients’ quality of life.

Other goals include measuring prostate-specific antigen (PSA) response, a common method to monitor treatment effectiveness; time to PSA progression, which correlates with disease progression; and overall survival.

Enrollment — estimated at a total of 96 patients — is currently ongoing. For more information on enrolling, click here. The trial is expected to be completed by June 2022.

A second open-label, multicenter Phase 1/2 trial, PROfind (NCT03490032), will evaluate prostate cancer diagnosis and staging through positron emission tomography (PET) imaging with 68Ga-PSMA-R2 in men whose PSA levels increased or whose disease spread to distant locations.

The trial will primarily assess the safety and tolerability of a one-time administration of 68Ga-PSMA-R2. Secondary goals include evaluating its pharmacokinetics, body distribution, and dosimetry, as well as comparing it with conventional imaging options. Pharmacokinetics refers to the study of drug absorption, distribution, metabolism, and excretion.

Patient recruitment is also ongoing. The company expects to enroll approximately 30 patients in the trial. For more information on enrolling, click here. AAA expects to complete the PROfind study in June 2019.

AAA, which is owned by Novartis, signed an exclusive license agreement with Johns Hopkins University for the development and marketing of PSMA-R2 in prostate cancer.