Outcomes of First-line Olaparib Mono-maintenance therapy-a Multicenter, Retrospective Study Using Data From Real-world Clinical Setting

Outcomes of First-line Olaparib Mono-maintenance Therapy in Newly Diagnosed Ovarian Cancer Patients With tBRCA Wild-type Tumors: a Realworld Study

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 + 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, olaparib mono-maintenance therapy has been implemented among patients with BRCA-wild type tumors in clinical practice in China.

The main objective is to evaluate the outcome of olaparib-based maintenance therapy by proportion of patients alive and progression free at 1 year (1-yr PFS rate) We hypothesize that olaparib monotherapy 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-based 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 dose adjustment, dose interruptions, and dose discontinuations; 6) Reason for use of concomitant therapy.

The exploratory objective is to evaluate the status quo of genetic testing, R0 resection and related outcomes.

Inclusion Criteria:

Patients are eligible to be included in the study only if they met all the following criteria:

• Female Patients must be ≥18 years old at diagnosis.
• Patients with newly diagnosed, histologically confirmed, advanced (FIGO stage III-IV) ovarian cancer, primary peritoneal cancer and / or fallopian-tube cancer and received olaparib from Aug 2018 up to Dec 2020 (the time range could be extended in order to recruit enough eligible subjects as required).
• Patients must have a tumor BRCA testing result which is tBRCAwt, defined as tumor BRCA wild type (patients without evidence of BRCA 1 and/or BRCA 2 deleterious or suspected deleterious mutations).
• Patients who have completed first-line platinum-based chemotherapy and were in clinical complete response (CR) or in partial response (PR).
• Patients who were still in CR or PR before receiving maintenance therapy.
• Patients who received at least one dose of olaparib tablets monotherapy as maintenance therapy within three months after platinum-based chemotherapy and without disease progression.

Exclusion Criteria:

Patients are excluded if any of the following factors were present:

• Patient with multiple primary cancers as reported in EMR.
• Concomitant any anti- cancer therapy (chemotherapy, immunotherapy, hormonal therapy (Hormone replacement therapy (HRT) is acceptable), radiotherapy, biological therapy or other novel agent) during Olaparib maintenance.
• Any previous treatment with PARP inhibitor.
• Patients with myelodysplastic syndrome/acute myeloid leukaemia or with features suggestive of MDS/AML.
• Patients with symptomatic uncontrolled brain metastases.
• Any other concerns related to decreased efficacy and safety of maintenance therapy.