IPAX-2 (ClinicalTrials.gov Identifier: NCT05450744) is a Phase I dose escalation study to confirm safety profile of TLX101 in combination with external beam radiation therapy (EBRT) and temozolomide in front-line glioblastoma. Twelve patients are expected to be recruited to evaluate whether the observed safety and drug interaction profile remains suitable in this setting before progressing to a proof-of-concept Phase II study.

IPAX-2 is being conducted at six sites across Australia, New Zealand and Europe. The study will build on data generated in IPAX-1 (ClinicalTrials.gov Identifier NCT03849105), which reported final results in September 2022.^[1] The IPAX-1 study met its primary objective demonstrating safety and tolerability profile of intravenous ¹³¹I-IPA administered concurrently with second line EBRT. The study also delivered encouraging preliminary therapeutic effect, demonstrating a median overall survival of 13 months from the initiation of treatment in the recurring setting, or 23 months from initial diagnosis.

Professor Josef Pichler, Kepler University Hospital, Austria and Principal Investigator in the IPAX-2 study said, "Promising efficacy data observed in IPAX-1 clearly warrants further investigation in an earlier setting. We are therefore pleased to be exploring Telix's glioblastoma therapy candidate in newly diagnosed patients, to accelerate development in this underserved disease area with few effective treatment options."

Dr. Colin Hayward, Telix Chief Medical Officer added, "Commencing this study supports Telix's goal to expedite new radiopharmaceutical therapies in areas of unmet need. With IPAX-2, we are taking the development of TLX101 into front-line glioblastoma for the first time, and excited to see the potential impact of targeted radiation in patients after initial surgery."

Telix's investigational positron emission tomography (PET) agent TLX101-CDx (¹⁸F-FET) will be used for imaging in the study to identify participants with over-expressed LAT-1 as suitable candidates for ¹³¹I-IPA therapy, and to provide baseline and follow up information on tumour response and progression.

In parallel to IPAX-2, TLX101 is being further investigated in the recurrent setting in the investigator-initiated Phase II IPAX-Linz study, which dosed a first patient in November 2022^[2] and has now exceeded 70% of the patient enrolment target.