Boston — Alpha-9 Oncology said it has dosed the first patient in a Phase 1 clinical trial evaluating two GRPR-targeted radiotherapeutics in patients with breast cancer and other advanced solid tumors.
The study is assessing 225Ac-A9-0642, an actinium-225-based therapy, and 177Lu-A9-0631, a lutetium-177-based therapy. Both target gastrin-releasing peptide receptor, or GRPR, which is expressed in several solid tumors.
“Dosing the first patient in our Phase 1 GRPR trial represents a significant milestone in Alpha-9’s journey as we seek to deliver the next wave of radiotherapeutic breakthroughs,” said Paul Blanchfield, Chief Executive Officer of Alpha-9.
“We believe our holistically optimized, distinct GRPR compounds have the potential to provide meaningful benefit to those living with cancer. Running both 225Ac and 177Lu programs in parallel allows us to efficiently generate data and validate our modular optimization platform.”
The Phase 1 trial is designed to evaluate safety, tolerability, dosimetry and recommended doses for expansion of both compounds in patients with GRPR-positive advanced or metastatic tumors.
Alpha-9 will use its proprietary GRPR imaging agent, 68Ga-A9-6217, to identify patients whose tumors express the target.
The company said 225Ac-A9-0642 is the first actinium-based GRPR-targeting compound to enter clinical evaluation. Alpha-9 is developing the treatment as a potential next-generation approach compared with earlier lutetium-based radiotherapies.
177Lu-A9-0631 is a separate beta-emitting GRPR-targeting radiotherapeutic being developed in parallel.
“Diagnostic imaging data generated with 68Ga-A9-6217 demonstrated excellent tumor targeting and limited healthy organ uptake,” said Robert S. Meehan, M.D., Chief Medical Officer of Alpha-9.
“Additionally, early results from access under compassionate use showed that 177Lu-A9-0631 was well tolerated in individuals with GRPR-positive tumors and we look forward to generating additional data for both our alpha- and beta-emitting compounds.”
Alpha-9 said GRPR is expressed across breast cancer and other solid tumors while showing a favorable expression profile in healthy organs, making it a potential target for radiotherapeutic development.
Initial data from the Phase 1 study are expected in late 2027.
