The phase III SPARTAN study evaluated Apalutamide ( Erleada ) vs Placebo in patients with non-metastatic castration-resistant prostate cancer ( nmCRPC ) who had prostate-specific antigen doubling time of less than or equal to 10 months and were receiving ongoing androgen deprivation therapy ( ADT ).
At primary analysis, Apalutamide significantly improved metastasis-free survival ( MFS ) and extended time to metastasis, progression-free survival ( PFS ), and time to symptomatic progression versus Placebo ( Smith NEJM 2018 ) while preserving health-related quality of life ( HRQoL ) ( Saad Lancet Oncol 2018 ).
At final analysis, Apalutamide significantly improved overall survival ( OS ) and time to chemotherapy versus Placebo ( Small ASCO 2020 ).
Researchers have evaluated HRQoL in SPARTAN after longer follow-up.
1207 nmCRPC patients were randomized 2:1 to Apalutamide ( 240 mg daily [ QD ] ) or Placebo.
HRQoL was assessed using Functional Assessment of Cancer Therapy-Prostate ( FACT-P ) and EQ-5D-3L at baseline and Day 1 of: cycle 1 ( pre-dose ), cycles 2-6, every 2 cycles from 7 to 13, and every 4 cycles thereafter during treatment, end of treatment, and every 4 months post progression for up to 1 year.
Each cycle was 28 days.
With 52 months follow-up, median treatment durations were 32.9 months ( Apalutamide ) and 11.5 months ( Placebo ).
Patients were minimally symptomatic, with good HRQoL at baseline.
At each cycle, more than 90% of patients in each group completed questionnaires.
Per LSM-MMRM, change in FACT-P total score from baseline to cycles 21 and 25 significantly favored Apalutamide vs Placebo ( p = 0.0138 and 0.0009, respectively ).
The Apalutamide group generally maintained favorable scores for FACT-P ( total and subscales ) and EQ-5D-3L, while Placebo group scores tended to decline over time ( separation between Apalutamide and Placebo started at cycles 11-15 and was more pronounced by cycles 21-25 ).
Of note, responses to individual items on FACT-P indicated most patients were not at all bothered by side effects and bother did not increase over time with Apalutamide or Placebo.
In conclusion, longer term SPARTAN data confirmed Apalutamide + androgen deprivation therapy improved metastasis-free survival and overall survival in patients with non-metastatic castration-resistant prostate cancer while preserving HRQoL, whereas HRQoL of patients receiving Placebo + androgen deprivation therapy declined after approximately 1 year. ( Xagena )
Source: European Society for Medical Oncology ( ESMO ) Virtual Meeting, 2020