NEW YORK – Telix Pharmaceuticals said on Tuesday that the first patient has been dosed in a Phase II trial of TLX250-CDx (89Zr-DFO-girentuximab) for triple-negative breast cancer.
The St. Herblain, France-based trial, dubbed OPALESCENCE, is designed to assess how well carbonic anhydrase IX (CA9) imaging with positron emission tomography can diagnose and stage TNBC patients, and whether CA9, a transmembrane protein overexpressed across multiple cancer types, might be used as a target for a future radiotherapeutic.
Should the trial, which aims to enroll 12 patients, demonstrate that TLX250-CDx can detect TNBC tumor lesions with its radiolabeled monoclonal antibody that targets CA9 expressed on cancer cells, and do so with results that are comparable to conventional imaging, this may enable the firm to develop a new targeted therapy using TLX250 radiolabeled with a therapeutic radionuclide such as 177Lutetium, Telix said. The study, in effect, is serving as a proof of concept to see if targeting CA9 with TLX250 might be an effective strategy to treat TNBC should the firm attach a tumor-killing payload to the diagnostic.
The strategy that Telix — in partnership with the French Institut de Cancérologie de l’Ouest (ICO)'s principal investigator Caroline Rousseau — is evaluating in the Phase II trial is one that the firm has so far applied chiefly to treating kidney cancer. Specifically, Telix is evaluating the CA9 program for clear cell renal cell carcinoma, or ccRCC, through a Phase III imaging trial dubbed ZIRCON and a Phase II therapy trial dubbed STARLITE.
Telix, which is headquartered in Melbourne, Australia, but also maintains operations in Liége, Belgium, is now focusing on expanding the CA9 program into cancers beyond ccRCC, and this TNBC trial marks the second indication that the firm is focusing on. Already, it has launched a study targeting CA9 in urothelial carcinoma or bladder cancer, and has its eyes on expanding into ovarian, colorectal, head and neck, lung, and pancreatic cancers.
"Telix is very pleased to see a first patient dosed in this important study of TLX250-CDx in TNBC, an aggressive breast cancer subtype that is poorly served by current tracers," Colin Hayward, Telix's chief medical officer, said in a statement. "Should the targeting properties of this PET/CT imaging tracer be established in TNBC, our intention is to broaden future applications for Telix's lutetium-177 and actinium-225 based CA9 therapies."