Telix Pharmaceuticals readies recruitment for phase 3 trial in renal cancer

Melbourne-based biopharmaceutical company Telix Pharmaceuticals (ASX: TLX) is preparing to commence recruitment for its zirconium imaging in renal cancer oncology (ZIRCON) phase 3 trial for imaging of clear cell renal cell cancer (ccRCC) with 89Zr-girentuximab (TLX250), one of the company’s leading therapeutic drugs.

TLX250 is being developed as both a therapeutic drug and a diagnostic PET imaging agent, denoted as TLX250-CDx. TLX250 is an antibody-based platform that targets what’s known as carbonic anhydrase IX (CAIX), a cell surface target that is over-expressed in several serious cancers, including: renal, lung, colorectal and oesophagal.

At the current time, Telix has prioritised the development of TLX250 for metastatic renal cell cancer (RCC), particularly the clear cell variant (ccRCC), which almost ubiquitously over-expresses CAIX.

Telix is currently developing a range of diagnostic and therapeutic products based on targeted “radiopharmaceuticals”, otherwise known as “molecularly-targeted radiation” (MTR).

The company wants to leverage the ZIRCON study to advance its development and potentially generate commercial marketability in the foreseeable future.

ZIRCON is a global multi-centre phase 3 study with at least 15 sites in Europe, Australia and the US, although Telix must still seek regulatory approval to conduct further clinical trials.

In essence, ZIRCON is a prospective imaging trial in approximately 250 renal cancer patients undergoing kidney surgery, and “will determine the sensitivity and specificity of TLX250-CDx PET imaging to detect clear cell renal cell cancer (ccRCC) in comparison with histologic “ground truth” determined from surgical resection specimens”.

Solutions for renal cancer imaging

The opportunity for advanced renal cancer imaging techniques consists of several distinct clinical needs, ranging from patients with an incidental discovery in the kidney, to diagnosed patients undergoing staging (or re-staging), and for treatment response assessment.

According to Telix, the company is now preparing to recruit patients at a total of four clinical sites in Australia after completing a Clinical Trial Notification (CTN) submission to the Therapeutic Goods Administration (TGA) and now receiving its first Human Research Ethics Committee (HREC) approval in Australia.

Telix is advancing a potentially breakthrough imaging technique that could help improve conventional techniques.

Kidney cancer patients are commonly mis-staged as metastases may be very small and do not typically image well using existing techniques.

In the US and the EU, there are roughly 120,000 new diagnoses each year, where more precise diagnostic imaging tools would significantly impact patient care. In the US alone, the prevalence of ccRCC is approximately 450,000 patients (SEER), a large proportion, of which, would benefit from better imaging for staging and treatment response.

“As an Australian-headquartered company, it’s very pleasing to be able to start to recruit patients in our own backyard while we finalise the regulatory documentation in the various international jurisdictions,” said Dr Christian Behrenbruch, chief executive officer of Telix

Mr Behrenbruch has also confirmed that Telix plans to bring online additional international sites before the end of this year due to its EU regulatory submissions “progressing well” with several key review milestones in November on the horizon.

“In all the countries we plan to run the ZIRCON study, there has been a high level of clinician engagement and we expect this trial to recruit well,” said Mr Behrenbruch.