Impact of prior local therapy on efficacy of first-line apalutamide for nonmetastatic castrate-resistant prostate cancer: secondary analysis of SPARTAN

Preclinical studies suggest that exposure to prostate-directed local therapy (radical prostatectomy, radiotherapy, or both) may influence the efficacy or subsequent systemic therapy. A secondary analysis of the randomized SPARTAN trial (first-line apalutamide plus ADT versus placebo plus ADT for nonmetastatic castration-resistant prostated cancer; nmCRPC) evaluated the impact of prior local therapy on efficacy of apalutamide. In this analysis of 1179 nmCRPC patients a differential treatment effect of apalutamide on metastasis-free survival (MFS) was seen between patients with and without prior local therapy, with greater MFS benefit among those with prior local therapy. There was no difference in treatment effect on overall survival between the two subgroups. The authors conclude that although these findings are hypothesis generating, they indicate a possible synergy between local therapy and apalutamide in patients with nmCRPC.