Head-to-Head Comparison of ⁶⁸Ga-NOTA (⁶⁸Ga-NGUL) and ⁶⁸Ga-PSMA-11 in Patients with Metastatic Prostate Cancer: A Prospective Study

Abstract

Ga-NOTA Glu-Urea-Lys (NGUL) is a novel prostate-specific membrane antigen (PSMA)-targeting tracer used for PET/CT imaging. This study aimed to compare performance in the detection of primary and metastatic lesions and to compare biodistribution between 68 Ga-NGUL and 68 Ga-PSMA-11 in the same patients with prostate cancer. Methods: Eleven patients with metastatic prostate cancer were prospectively recruited. The quantitative tracer uptake was determined in normal organs and in primary and metastatic lesions. Results: 68 Ga-NGUL showed significantly lower normal-organ uptake and rapid urinary clearance. The number and sites of detected PSMA-positive primary and metastatic lesions were identical, and no significant quantitative uptake difference was observed. 68 Ga-NGUL showed a relatively lower tumor-to-background ratio than 68 Ga-PSMA-11. Conclusion: In a head-to-head comparison with 68 Ga-PSMA-11, 68 Ga-NGUL showed lower uptake in normal organs and similar performance in detecting PSMA-avid primary and metastatic lesions. 68 Ga-NGUL could be a valuable option for PSMA imaging.

Phase I Clinical Trial of Prostate-Specific Membrane Antigen-Targeting 68Ga-NGUL PET/CT in Healthy Volunteers and Patients with Prostate Cancer

“…Radiotracer activity in the bladder majorly contributed to effective dose, and for this reason, the effective dose was also relatively higher than that of PSMA-11 (0.025 mSv/MBq vs. 0.017 mSv/MBq). However, exposure to other organs, including the kidney (0.332 mGy/MBq vs. 0.371 mGy/MBq) and spleen (0.022 mGy/MBq vs. 0.065 mGy/MBq), was lower than that of 68 Ga-PSMA-11, which is in line with the results of a previous comparative study [ 8 ]. The lower molecular weight (769.82 g/mol vs. 947 g/mol) and higher hydrophilicity (log P = -3.3 vs. -3.9) of 68 Ga-NGUL compared with 68 Ga-PSMA-11 may explain the difference in the urinary excretion.…”

“…As previously reported in a comparative study of 68 Ga-PSMA-11, rapid urinary excretion of 68 Ga-NGUL was observed [ 8 ]. Accordingly, it was estimated that the urinary bladder wall had the highest absorbed dose.…”

“…68 Ga-NGUL can be considered more stable than tracers containing amide bonds because amide bonds are susceptible to degradation by proteolytic enzymes in the body [ 7 ]. In a head-to-head comparison study with 68 Ga-PSMA-11, 68 Ga-NGUL exhibited similar performance in detecting PSMA-avid lesions [ 8 ]. Thus, 68 Ga-NGUL can be considered a valuable option for PSMA-targeting PET/CT imaging and its theranostic applications.…”

An Update of Prostate-Specific Membrane Antigen Theranostics in Prostate Cancer

“…National Comprehensive Cancer Network guideline 을 살펴보면 68 Ga-PSMA-11과 18 [17][18][19][20] 또한, 전립선외에도 침샘, 신장, 소장, 간, 비장 등 다른 장기에서 낮은 수준으로 PSMA가 발현되는 것으로 알려져 있다. 21,22 그 외에도 아직까지 정확한 이유는 밝혀 져 있지 않지만 다른 고형암들의 종양관련 신생혈관 부위 에서도 PSMA의 발현도가 높게 관찰된다.…”

“…[23][24][25] 3. Action of PSMA-Targeted Theranostic Agent Ga-PSMA-11, 18 F-PSMA-11, 18 F-PSMA-1007, 18 F-rhPSMA 7.3, 68 Ga-PSMA-617, 68 Cu-PSMA-I&T, 44 Sc-PSMA-617 등이 전임상 및 임상 연구에 활발히 적용되기 시작하였다. 34 2.…”