Understanding the Factors Related to Early Discontinuation of Lutetium-177 Vipivotide Treatment in Men With Metastatic Castration-Resistant Prostate Cancer at a Single Institution.

Background Lutetium-177 vipivotide tetraxetan (Lu-177 vipivotide) is a radiopharmaceutical treatment for metastatic castration-resistant prostate cancer (mCRPC). Understanding the factors that hinder treatment completion with Lu-177 vipivotide may enable clinicians to predict treatment tolerability. This retrospective review evaluates the factors associated with incomplete treatment or early discontinuation of Lu-177 vipivotide in patients with mCRPC. Methodology Patients with mCRPC who had progressed on androgen deprivation therapy and taxane chemotherapy with positive uptake on prostate-specific membrane antigen positron emission tomography imaging were treated with Lu-177 vipivotide. Initial laboratory tests included a white cell count, platelet count, hemoglobin, total bilirubin, aspartate aminotransferase, alanine aminotransferase, and creatinine. The ability to perform tasks independently was assessed using the Karnofsky Performance Scale (KPS) score. Electronic medical records were reviewed, and patients were prescribed Lu-177 vipivotide 200 mCi, administered once every six weeks, for a total of six infusions. To evaluate the original KPS, the Mann-Whitney U test was utilized. For other variables, Student's t-tests were used. Results In total, 23 patients received Lu-177 vipivotide therapy. Overall, 10 patients completed therapy, while 13 patients did not, with a median of three cycles completed. A significant difference was found between the initial mean hemoglobin for those who did not complete treatment (12.22 g/dL) and the initial mean hemoglobin for those who completed all six cycles (9.53 g/dL, p = 0.006). A significant difference was found between the median KPS score in those who completed treatment and those with early discontinuation (80 vs. 70, p = 0.005). Neither the initial platelet count (272.90 K/cumm vs. 219.15 K/cumm) (p = 0.280) nor the mean age (72.4 years vs. 75.5 years, p = 0.321) was statistically correlated with treatment completion for those who completed treatment compared to those who did not. Conclusions Low KPS score and low hemoglobin were significantly associated with those who had incomplete Lu-177 vipivotide therapy.