Telix has dosed the first patient in a Phase 3 trial evaluating its radiopharmaceutical therapy TLX250-Tx in relapsed or recurrent clear cell renal cell carcinoma.

Telix Pharmaceuticals has dosed the first patient in a Phase 3 trial evaluating its investigational radiopharmaceutical therapy TLX250-Tx in patients with relapsed or recurrent clear cell renal cell carcinoma (ccRCC).

The LUTEON study is evaluating lutetium-177 (177Lu) girentuximab tetraxetan, a CAIX-targeted radiopharmaceutical therapy, in patients with advanced ccRCC. It is the first Phase 3 study of a CAIX-targeted radiopharmaceutical therapy in the disease.

The first patient was dosed at GenesisCare Murdoch in Western Australia, under the supervision of Aviral Singh, clinical head of theranostics and nuclear medicine at GenesisCare Murdoch and principal investigator on the LUTEON trial.

LUTEON is a randomised, prospective, open-label, multi-centre study evaluating the safety, tolerability and efficacy of TLX250-Tx. The trial will assess the treatment as a monotherapy against investigator’s choice of monotherapy consistent with standard of care.

The study forms part of Telix’s global development programme for TLX250-Tx, which also includes the separate LUTEON ATLAS Phase 2a study in the US and Europe.

TLX250-Tx is designed to target carbonic anhydrase IX (CAIX), a protein expressed in more than 95% of clear cell renal cell carcinomas but with limited expression in normal tissues, including the kidneys.

The treatment consists of a monoclonal antibody targeting CAIX that is linked to the therapeutic radionuclide lutetium-177. The approach is intended to deliver targeted radiation to tumour sites while limiting exposure to healthy tissue.

Patients in the LUTEON study will be selected using Telix’s investigational PET imaging agent TLX250-Px, also known as Zircaix, which uses zirconium-89 (89Zr) girentuximab senvedoxam to identify patients with CAIX-positive tumours.

Aviral Singh said: “Dosing the first patient in the LUTEON study marks an important milestone in the development of potential new treatment options for patients with relapsed or recurrent clear cell renal cell carcinoma.”

He added that the study would evaluate the safety, tolerability and efficacy of the investigational CAIX-targeted radiopharmaceutical in patients globally.

Telix group chief medical officer David Cade said: “LUTEON represents the next stage in Telix’s global clinical development of TLX250-Tx and reflects our commitment to developing precision radiopharmaceuticals for patients with difficult-to-treat cancers.”

He added that the company aimed to further evaluate the potential of TLX250-Tx, which is designed to use the high prevalence of CAIX expression in ccRCC to deliver targeted radiation directly to tumour sites.

Clear cell renal cell carcinoma is the most common subtype of renal cell carcinoma and accounts for about 85% of all RCC cases. Up to 30% of patients present with metastatic disease at diagnosis, according to the information provided by Telix.

The company said outcomes remain poor for many patients with advanced disease, highlighting the need for additional treatment options.

TLX250-Tx and TLX250-Px have not received marketing authorisation in any jurisdiction and remain investigational therapies.