Background: Treatment options for mCSPC patients include adding novel hormonal therapy (NHT) with/without docetaxel (DOC) to androgen deprivation therapy (ADT). Uptake of these agents has been slow, and safety concerns may contribute to therapeutic inertia. This study aims to understand the RW occurrence of prespecified AEs among pts with mCSPC in the US. Methods: Claims from the PharMetrics Plus database (IQVIA, Durham, NC) were used to retrospectively estimate the proportion of pts with AEs among those with mCSPC from Jan 2014 through Jun 2021. Common AEs (≥10%) specified in FDA labels of treatments of interest or clinical trials ≥2% more prevalent than ADT alone were included in the study. Results of four clinically important AEs (fatigue, hot flash, sexual function and gastrointestinal [GI] AEs) are reported here. The proportions of pts with each of these AEs at specific timepoints plus 95% confidence intervals (CI) were estimated from cumulative hazard plots. Results were adjusted using inverse probability of treatment weighting across ADT alone, ADT+ nonsteroidal antiandrogen (NSAA), ADT+DOC and ADT+NHT. Results: The mean age of the overall study population (N=4145) was 66 years. At baseline, common sites of metastasis were bone only (n=1886, 45.5%) and node only (n=1237, 29.8%); the most common medications used were for pain (n=2182, 52.6%) and corticosteroids (n=1213, 29.3%). The reference group for all comparisons of AEs was ADT alone. For the entire study period, GI AEs and fatigue were significantly higher only in the ADT+DOC group (P<0.001). Hot flash was higher in ADT+NHT (P=0.05) and the ADT+DOC groups (P<0.001). No statistically significant differences in sexual function AEs in the groups was noted. The table shows the proportions of pts with specified AEs. Conclusions: In this large RW study, all groups, including ADT alone, showed an increase in AE reporting over time. Most AE rates with ADT+NHT were comparable to ADT alone and ADT+NSAA, while ADT+DOC showed an increase in GI AEs, fatigue and hot flash.

NA, Not applicable. *Erectile/sexual dysfunction, decreased erections, impotence, decreased/loss of libido, testicular atrophy. ^#Constipation, diarrhea, GI disorder, nausea.