Collaborations progress clinical trial of 225Ac-rhPSMA-10.1 in mCRPC

Blue Earth Therapeutics has announced an expansion of their manufacturing agreement with Seibersdorf Labor GmbH to include the manufacture of ²²⁵Ac-rhPSMA-10.1, which will support a phase 1/2 clinical trial of the investigational radioligand therapy in patients with metastatic castration-resistant prostate cancer (mCRPC).¹

The phase 1/2 study of ²²⁵Ac-rhPSMA-10.1 will be conducted at the UCL Cancer Institute in London, UK.

Under the agreement expansion, Seibersdorf Labor GmbH will provide future supply of (²²⁵Ac) rhPSMA-10.1 to clinical trial sites in the United Kingdom (UK), the European Union, and the United States. This collaboration adds on to an existing agreement between the companies that included the manufacture of (¹⁷⁷Lu) rhPSMA-10.1.

“We are very pleased to add manufacture of our ²²⁵Ac-based investigational product to our partnership with Seibersdorf Labor,” said David E. Gauden, DPhil, CEO of Blue Earth Therapeutics Ltd, in the news release.¹ “It has the potential to be a product of high purity and stability, and this partnership will enable supply of the clinical trial sites in London, and other regions if necessary. Seibersdorf has been an excellent and collaborative partner, and we look forward to working with them on many more projects in the future.”

The expanded collaboration with Seibersdorf Labor GmbH comes on the heels of a previous announcement from Blue Earth Therapeutics on the signing of a clinical research collaboration with University College London (UCL).²

With this agreement, the phase 1/2 study of ²²⁵Ac-rhPSMA-10.1 will be conducted at the UCL Cancer Institute in London, UK, by the Treatment Resistance Group, led by Gerhardt Attard, MD, PhD, FRCP. Overall, the phase 1/2 trial is assessing the safety, tolerability, radiation dosimetry, and preliminary anti-tumor activity of ²²⁵Ac-rhPSMA-10.1 in men with mCRPC who have previously responded to lutetium 177 (¹⁷⁷Lu)-PSMA therapy.

“We are pleased to enter into this broad research collaboration with UK-based Blue Earth Therapeutics, as both of our institutions share a vision to improve cancer treatment for patients,” said Attard, who is the John Black Charitable Foundation Endowed Chair in Urological Cancer Research at UCL, in the news release.² “Despite the development of several new therapeutic options for castration resistant prostate cancer in the last 20 years, treatment resistance is common and leads to thousands of premature deaths annually in the UK. Precision-delivered radiation therapy using radioligands provides an opportunity for selectively targeting resistant prostate cancer. We believe that delivery of radiation by means of alpha particles is a very promising area of research and we look forward to starting clinical testing of rhPSMA-10.1 for patients with aggressive, treatment-resistant prostate cancer.”

In addition to the current study of ²²⁵Ac-rhPSMA-10.1, Blue Earth Therapeutics also has an ongoing phase 1/2 clinical trial (NCT05413850) of (¹⁷⁷Lu) rhPSMA-10.1 in patients with PSMA-expressing mCRPC.³ In total, the trial will enroll 150 patients across sites in the US and Europe.

The primary outcome measures are the incidence of dose-limiting toxicities, the frequency and nature of treatment-emergent adverse events, and preliminary anti-tumor response of (¹⁷⁷Lu) rhPSMA-10.1.

Study completion is anticipated for October 2026.

References

1. Blue Earth Therapeutics Ltd announces expansion of partnership with Seibersdorf Labor GmbH to include manufacture of therapeutic radiopharmaceutical, 225Ac-rhPSMA-10.1. News release. Blue Earth Therapeutics. Published online and accessed August 12, 2024. https://4078578.fs1.hubspotusercontent-na1.net/hubfs/4078578/News/Blue%20Earth%20Therapeutics/BET_Seibersdorf_partnership_press%20release.pdf

2. Blue Earth Therapeutics announces clinical research collaboration with UCL to develop innovative alpha-labelled radioligand therapy (RLT) for prostate cancer. News release. Blue Earth Therapeutics. July 23, 2024. Accessed August 12, 2024. https://4078578.fs1.hubspotusercontent-na1.net/hubfs/4078578/Blue%20Earth%20Therapeutics/Press%20Release/BET_UCL_agreement_press%20release_16_July_FINAL_CLEAN.pdf

3. Anti-tumour activity of (177Lu) rhPSMA-10.1 injection. ClinicalTrials.gov. Last updated March 4, 2024. Accessed August 12, 2024. https://clinicaltrials.gov/study/NCT05413850