The PROSPER trial has shown a clinically and statistically significant improvement in metastasis-free survival ( hazard ratio, HR=0.292 [ 95% CI 0.241, 0.352 ], p less than 0.0001 ) with Enzalutamide ( Xtandi; n = 933 ) versus placebo ( n = 468 ) in asymptomatic men with non-metastatic castration-resistant prostate cancer ( nmCRPC ) and prostate-specific antigen doubling time less than or equal to 10 months.
All men without prior orchiectomy continued androgen deprivation therapy.
Researchers have assessed the impact of Enzalutamide on prostate cancer symptoms and health-related quality of life ( HRQoL ).
Prostate cancer symptoms and HRQoL were assessed at baseline and subsequently every 16 weeks, using the EORTC Quality of Life Questionnaire-Prostate 25 ( QLQ-PR25 ) and the EuroQol 5-domain 5-level ( EQ-5D-5L ).
Clinically meaningful symptom worsening in prostate cancer symptoms scores was defined using thresholds derived as 1/2 standard deviation at baseline.
Clinically meaningful deterioration in EQ-5D-5L visual analogue scale was defined using the pre-established threshold of 7.
Time to first confirmed ( at two consecutive visits ) and unconfirmed ( one visit ) deterioration in QLQ-PR25 and EQ-5D-5L scores were assessed using Kaplan-Meier estimates and Cox models.
Completion rates were high for patients remaining on study ( more than 85% for all visits ).
Baseline scores were similar between arms and showed low symptom burden ( including urinary and bowel symptoms ) and high HRQoL.
The proportion of patients reporting either no change or improvement in HRQoL and prostate cancer symptoms scores at week 49 was higher with Enzalutamide ( 67 − 87% ) than placebo ( 62 − 81% ).
Over the course of treatment, Enzalutamide significantly delayed worsening of symptoms including urinary and bowel symptoms / function.
In contrast, Enzalutamide significantly increased the risk of worsening of hormonal treatment related symptoms compared to placebo.
In conclusion, in addition to delayed disease progression in the PROSPER trial, Enzalutamide prolonged urinary and bowel symptom control and delayed decline in HRQoL scores versus placebo. ( Xagena )
Source: European Society of Medical Oncology - ESMO Congress, 2018