PURPOSE This phase III trial aimed to explore the efficacy and safety of fuzuloparib (formerly fluzoparib) versus placebo as a maintenance treatment after response to second- or later-line platinum-based chemotherapy in patients with high-grade, platinum-sensitive, recurrent ovarian cancer. PATIENTS AND METHODS Patients with platinum-sensitive, recurrent ovarian cancer previously treated with at least two platinum-based regimens were assigned (2:1) to receive fuzuloparib (150 mg, twice daily) or matching placebo for 28-day cycles. The primary end points were progression-free survival (PFS) assessed by blinded independent review committee (BIRC) in the overall population and PFS by BIRC in the subpopulation with germline BRCA 1/2 mutation. RESULTS Between April 30, 2019, and January 10, 2020, 252 patients were randomly assigned to the fuzuloparib (n = 167) or placebo (n = 85). As of July 1, 2020, the median PFS per BIRC assessment in the overall population was significantly improved with fuzuloparib treatment (hazard ratio [HR], 0.25; 95% CI, 0.17 to 0.36; one-sided P < .0001) compared with that with placebo. The HR derived from a prespecified subgroup analysis showed a consistent trend of benefit in patients with germline BRCA 1/2 mutations (HR, 0.14; 95% CI, 0.07 to 0.28) or in those without mutations (HR, 0.46; 95% CI, 0.29 to 0.74). The most common grade ≥ 3 treatment-emergent adverse events reported in the fuzuloparib group were anemia (25.1%), decreased platelet count (16.8%), and decreased neutrophil count (12.6%). Only one patient (0.6%) discontinued fuzuloparib because of treatment-related toxicity (concurrent decreased white blood cell count and neutrophil count). CONCLUSION Fuzuloparib as maintenance therapy achieved a statistically significant and clinically meaningful improvement in PFS for patients with platinum-sensitive, recurrent ovarian cancer versus placebo, regardless of germline BRCA 1/2 mutation, and showed a manageable safety profile.