Positive Phase I Data of 177Lu rhPSMA-10.1 Supports Phase II Trial for mCRPC

Early phase I data on lutetium (177Lu) rhPSMA-10.1 for the treatment of metastatic castration-resistant prostate cancer (mCRPC) has demonstrated an encouraging safety profile for the novel radioligand therapy.

Developed by Blue Earth Therapeutics Ltd, 177Lu rhPSMA-10.1 was administered to patients in the phase I trial in July. Radiation dosimetry that was conducted for up to 3 cycles revealed high radiation doses absorbed by the tumor relative to the dose received by key normal organs, including the kidneys and salivary glands.

The ratio seen between radiation doses administered to tumors versus doses to the kidneys and salivary glands was compelling when compared with previously-published data on first-generation radioligand therapies.

Final analysis of the phase I trial is still ongoing, with phase II set to open later this year in approximately 15 sites across the US and Europe, enrolling about 70 patients.

The second phase of the trial will explore the administration of a high overall injected radioactivity in comparison to recent phase III trials of other agents, front-loading of administered radioactivity, and extending the duration of administration of radioactivity to provide longer time on treatment.

“The available science increasingly highlights that fixed dosing at fixed intervals is unlikely to be optimal,” commented Dr. Daniel Stevens, Head of Clinical Development and Medical at Blue Earth Therapeutics Ltd. “Front loading radioactivity and extending the time on therapy may lengthen time to disease progression…our intention is to optimize dosing now, with the aim of achieving the best possible outcomes for patients in a future pivotal trial.”

David Gauden, CEO of Blue Earth Therapeutics Ltd, noted that the company “remain[s] on track for the opening of phase II in the next few months. We also expect to see the full phase I results presented at a scientific meeting in 2025.”