[99mTc]Tc-HYNIC-iPSMA shows promise in prostate cancer imaging

Interim results from the real-world NOBLE registry show initial safety and efficacy of [^99mTc]Tc-HYNIC-iPSMA (TLX599-CDx) in identifying prostate-specific membrane antigen (PSMA)-positive prostate cancer on SPECT/CT imaging.¹

[^99mTc]Tc-HYNIC-iPSMA imaging caused a change of treatment in 42.5% of patients.

NOBLE is a global real-world evidence study aiming to collect data to inform the development of the investigational tracer [^99mTc]Tc-HYNIC-iPSMA as well as to increase access to prostate cancer imaging, according to Telix Pharmaceuticals.²

“The NOBLE Registry is an important initiative for increasing access to medicine globally, particularly for men in regional and remote locations,” said lead author Pete Tually, BAppSci, ANMS, MSc,PhD (candidate), FACHI, director of TeleMed Remote Nuclear Medicine and principal investigator for the Australian arm of NOBLE, in a news release on the findings.² “The interim results reported in our manuscript are promising, and we believe they provide a compelling basis for the further clinical study of technetium-99m-based PSMA imaging of prostate cancer.”

In the interim report of the findings, published in the European Journal of Nuclear Medicine and Molecular Imaging (EJNMMI) Reports, data was available for 40 patients. These patients were enrolled across 6 countries, with an average age at imaging of 68 ± 7.2 years. The majority of patients enrolled were Caucasian (67.5%).

Those enrolled received the [^99mTc]Tc-HYNIC-iPSMA tracer and then underwent planar and SPECT imaging.

Overall, data showed that [^99mTc]Tc-HYNIC-iPSMA SPECT imaging was able to detect at least 1 PSMA-positive lesion in 77.5% (31/40) of patients. Among these patients, lesions were identified in the prostate or prostate bed in 48.3% (n = 15) of patients, in the bones in 32.2% (n = 10) of patients, in the local, regional lymph nodes in 3.2% (n = 1) of patients, and in all of these locations in 16.1% (n = 6) of patients.

When stratified by prostate-specific antigen (PSA) levels, the detection rate for [^99mTc]Tc-HYNIC-iPSMA was 16.6% at PSAs of 0-2 ng/mL, 83.3% at PSAs of > 2–10 ng/mL, and 89.2% at PSAs of greater than 10 ng/mL.

Findings also revealed that [^99mTc]Tc-HYNIC-iPSMA imaging caused a change of treatment in 42.5% of patients (n = 17).

Regarding safety, no adverse events were observed.

In total, the prospective, observational, multinational registry plans to enroll 100 patients.

Patients are eligible for enrollment if they are 18 to 80 years of age and plan to undergo imaging for primary staging or metastatic prostate cancer. Patients are not eligible for enrollment if they are unable to perform prescribed examinations, undergo a [^99mTc]Tc-HYNIC-iPSMA planar and SPECT or SPECT/CT, or sign an informed consent form.

The primary objective of the study is to assess the safety and tolerability of [^99mTc]Tc-HYNIC-iPSMA administration. The secondary objective is to determine the clinical utility of the [^99mTc]Tc-HYNIC-iPSMA SPECT imaging in detecting disease across different prostate cancer stages.

The authors highlight several limitations of the current assessment, including a small sample size with a lack of diversity as well as the absence of long-term data. These findings, they note, warrant further long-term follow-up to accurately assess the safety and clinical utility of [^99mTc]Tc-HYNIC-iPSMA.

They concluded, “[^99mTc]Tc-HYNIC-iPSMA is a promising option to identify PSMA-positive [prostate cancer] on SPECT imaging with the potential for improving patient access to imaging worldwide across various indications, patient PSA levels, and scanner types.”

References

1. Tually P, Quinto VG, Omar Y, et al. Real world experience with [99mTc]Tc-HYNIC-iPSMA SPECT prostate cancer detection: interim results from the global NOBLE registry. EJNMMI Rep. 2024;8(1):43. doi:10.1186/s41824-024-00226-4

2. NOBLE Registry update: TLX599-CDx PSMA SPECT imaging of prostate cancer published in EJNMMI Reports. News release. Telix Pharmaceuticals Limited. December 31, 2024. Accessed January 3, 2025. https://telixpharma.com/news-views/noble-registry-update-tlx599-cdx-psma-spect-imaging-of-prostate-cancer-published-in-ejnmmi-reports/