A phase II study evaluating pharmacokinetics and dosimetry of 177Lu-PSMA-617 radioligand therapy in Chinese participants with progressive metastatic castration-resistant prostate cancer.

BACKGROUND

177Lu-PSMA-617 is a radioligand therapy targeting cells expressing prostate-specific membrane antigen (PSMA). The pharmacokinetics, dosimetry, and safety of 177Lu-PSMA-617 in participants with metastatic castration-resistant prostate cancer are described previously. In this study, we describe the blood pharmacokinetics behavior, biodistribution, and dosimetry of 177Lu-PSMA-617 to support its clinical use in Chinese participants.

RESULTS

Nine participants were infused with 177Lu-PSMA-617 (range: 6985.6–8036.0 MBq). The geometric (Geo)-mean blood terminal half-life was 52.6 h, corresponding to an effective half-life of approximately 40 h. The Geo-mean maximum blood concentration of 11.3 ng/mL was achieved at a median time of 0.217 h post administration. The Geo-mean volume of distribution and clearance were 123 L and 1.62 L/h, respectively. The lacrimal glands received the highest absorbed dose of 3.1 mGy/MBq (Geo-coefficient of variation, 93.7%), followed by the thyroid, kidneys, and salivary glands. The Geo-mean whole-body effective dose was 890 mSv (Geo-coefficient of variation, 112.4%).

CONCLUSIONS

The blood pharmacokinetics and organ dosimetry of 177Lu-PSMA-617 in Chinese participants with progressive metastatic castration-resistant prostate cancer were consistent with those previously reported. The cumulative absorbed dose, corresponding to six cycles of treatment, was consistent with published literature. This analysis was conducted as part of a phase II study registered as NCT05670106 at ClinicalTrials.gov on November 7, 2022.