The main objective is to evaluate the outcome of olaparib plus bevacizumab combination maintenance therapy by proportion of patients alive and progression free at 1 year (1-yr PFSrate) We hypothesize that olaparib plus bevacizumab maintenance therapy could be beneficial for tBRCAwt high-grade serous ovarian cancer (HGSOC) patients who are treated with platinum-based first-line chemotherapy.~The secondary objectives are to evaluate the outcomes of olaparib plus bevacizumab maintenance therapy by: 1) 2-yr PFS rate; 2) median PFS; 3) median Time to First Subsequent Therapy or death (mTFST) ; 4) post-progression treatment after first progression; 5) reason for olaparib plus bevacizumab dose adjustment, dose interruptions, and dose discontinuations; 6) Reason for use of concomitant therapy.
Four phase III trials in ovarian cancer consistently showed that front-line poly(ADP-ribose) polymerase (PARP) inhibition can significantly improve progression-free survival. Based on these findings, current clinical guidelines recommend the olaparib plus bevacizumab combination as a maintenance therapy for ovarian cancer patients with BRCA1/2 wild-type or unknown mutation status who have a complete response (CR)/ partial response (PR) after completing bevacizumab-containing first-line therapy. However, bevacizumab is not a NATIONAL MEDICAL PRODUCTS ADMINSTRATION（ NMPA） -approved agent for ovarian cancer patients. In this setting, there is no olaparib plus bevacizumab maintenance therapy RWS data amongst 1st tBRCAwt patients in China, while this treatment regimen has been used in Chinese clinical practise by some doctors based on above-mentioned data.