MCRPC: SRE rates top 34% in PREVAIL and AFFIRM studies

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Takeaway
  • Over a third of patients with metastatic castration-resistant prostate cancer (mCRPC) in the PREVAIL and AFFIRM trials experienced skeletal-related events (SREs). 
  • First SREs was significantly associated with functional decline and reduced health-related QoL (HRQoL). 
  • Spinal cord compression had the largest effect on HRQoL.

Why this matters

  • Delaying SREs is an important treatment goal in patients with mCRPC without major cancer-related symptoms in the chemotherapy-naïve setting.

Key results

  • In PREVAIL, 587 (34.2%) patients experienced ≥1 SRE. 
  • First SREs caused clinically meaningful declines in EQ-5D utility index
  • Spinal cord compression had the largest effect on utility index (trajectory-adjusted mean change [TAMC], −0.24) and Functional Assessment of Cancer Therapy-Prostate (FACT-P) total score (TAMC, –16.95). 
  • In AFFIRM, 421 (35.1%) experienced ≥1 SRE. 
  • There were clinically meaningful and statistically significant declines in FACT-P and FACT-General total scores after any SRE (TAMC, –6.94 and –5.46, respectively), and clinically meaningful declines in FACT-P prostate cancer subscale for spinal cord compression only (TAMC, –2.66).

Study design

  • Secondary endpoint data from PREVAIL and AFFIRM trials. 
  • Funding: Astellas Pharma and Medivation.

Limitations

  • HRQoL available for more enzalutamide than placebo patients in both trials.