1624P - Total and regional changes in body composition in metastatic hormone-sensitive prostate cancer (mHSPC) patients randomized to receive androgen deprivation + enzalutamide +/- zoledronic acid: The BonEnza study

Background

In patients with mHSPC, next-generation hormonal agents (NHGAs) are now the standard of care. Androgen deprivation therapy (ADT) is notoriously responsible for the reduction of lean body mass (LBM) and increase of fat body mass (FBM), leading to an increased risk of sarcopenic obesity, strictly associated with cardiovascular events, diabetes and metabolic syndrome. The additional effects of NHGAs associated to ADT have been poorly investigated.

Methods

BonEnza (NCT03336983) is a prospective phase II trial in which mHSPC patients were randomized to receive ADT plus enzalutamide with (EZ ARM) or without (E ARM) the addition of zoledronic acid. FBM and LBM were evaluated in different body regions by dual-energy x-ray absorptiometry (DEXA) scan at baseline and after 18 months of therapy.

Results

Among the 126 patients recruited, 89 patients (46 from EZ arm and 43 from E arm), had paired DEXA evaluation at both timepoints. After 18 months of therapy, FBM increased by +22.8% (p<0.001), LBM reduced by -6.7% (p<0.001) and Appendicular Mass Index (ALMI) decreased by -9.2% (p<0.001). Subgroup analysis showed that these changes significantly differed according to patients' age. There was no statistical difference in body composition changes between the two arms. None of the patients met the criteria for sarcopenic obesity¹, however after 18 months of treatment 11,76% of patients had %FBM >40.8 and 3,5% ALMI <5.5 and the ALMI/FBM ratio decreased by -23.9% (p<0.001). FBM increase considerably varies according to body districts: from +36.1% in the right arms (p<0.001) to +3.7% in the head (p<0.01). Similarly, LBM decrease ranged from -9.4% (p<0.001) in the right arm to -6.4% (p<0.001) in the trunk.

Conclusions

Body composition changes in patients with prostate cancer have more than doubled when Enzalutamide is added to ADT. The observed significant differences based on body districts can be used as a guide for supervised physical exercise which is required to prevent the high risk of sarcopenic obesity, 'especially in younger patients. 1. Donini LM et al. Clin Nutr. 2022 Apr;41(4):990-1000.

Clinical trial identification

NCT03336983.

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.