Cytoreductive surgery followed by chemotherapy and olaparib maintenance in BRCA 1/2 mutated recurrent ovarian cancer: a retrospective MITO group study

Poly (ADP-ribose) polymerase inhibitors (PARPi) in ovarian cancer: lessons learned and future directions

Poly (ADP-ribose) polymerase inhibitors (PARPi) represent a new standard of care in the upfront treatment of advanced epithelial ovarian cancer to the point that the vast majority of patients now receive a PARPi, alone or in combination with the anti-angiogenic bevacizumab, as part of their first-line maintenance therapy. The clinical benefit of PARPi is well established; however, much has changed since their introduction and several relevant questions have been raised and remain unresolved in the post-PARPi era. The decision-making process regarding the most appropriate first-line maintenance therapy could be challenging in clinical practice, especially in the homologous recombination-proficient setting, and several other factors need to be considered apart from the mutational status. Concerns regarding post-PARPi progression treatment have emerged, highlighting an unmet need to define a valid algorithm strategy. PARPi may not only compromise the response to further platinum due to cross-resistance mechanisms but the impact on subsequent non-platinum chemotherapy and surgery also remains unclear. Definitive results on the role of PARPi rechallenge are awaited, especially in the case of oligoprogression managed with locoregional treatment. Moreover, the updated overall survival data from the recurrent setting warrant caution in using PARPi as single agents for unselected patients. Several PARPi combination regimens are emerging for overcoming PARPi resistance and may become our new therapeutic armamentarium. This review discusses a set of clinically relevant issues in the PARPi era and provides a glimpse of future challenges and opportunities in ovarian cancer treatment.

The value of PET/CT for cytoreductive surgery selection in recurrent ovarian carcinoma

OBJECTIVE

To evaluate the value of positron emission tomography/computed tomography (PET/CT) in predicting no residual disease (NRD) after secondary cytoreductive surgery (SCS) compared with MSK criteria, the iMODEL, and the AGO score.

METHODS

We analyzed 112 patients with platinum-sensitive ovarian carcinoma who underwent SCS. We excluded patients for whom PET/CT was not performed, those without sufficient data, and who received chemotherapy before SCS. Ultimately, 69 patients were included.

RESULTS

Variables that correlated with NRD were peritoneal carcinomatosis index (odds ratio [OR]=0.91; 95% confidence interval [CI]=0.83-0.99; p=0.044), European Cooperative Oncology Group Performance Status (ECOG) 0 (OR=8.0; 95% CI=1.34-47.5; p=0.022), and ≤2 lesions by PET/CT (OR=4.36; 95% CI=1.07-17.7; p=0.039). Of the patients with ≤2 lesions by PET/CT, 48 (92.3%) underwent complete SCS. The sensitivity, positive predictive value, negative predictive value, and accuracy of PET/CT for NRD were 85.7%, 92.3%, 33.3%, and 81.2%, respectively. NRD was achieved after fulfilling the MSK criteria, iMODEL and AGO Score in 89.1%, 88.1% and 85.9%, respectively. The accuracy of the MSK criteria, iMODEL, and AGO score in predicting NRD was 87%, 83.3%, and 77.3%, respectively. The PET/CT findings agreed well with the AGO score and iMODEL. The addition of PET/CT to these models increased the NRD rates (92.2%, 91.8%, and 89.4% for MSK+PET/CT, iMODEL+PET/CT, and AGO+PET/CT, respectively), but lowered their accuracy.

CONCLUSION

We observed NRD in 92.3% of patients with ≤2 lesions by PET/CT, with an accuracy of 81.2%. PET/CT did not increase the accuracy of the MSK criteria, iMODEL, or AGO score models.

Olaparib beyond progression compared with platinum chemotherapy after secondary cytoreductive surgery in patients with recurrent ovarian cancer: phase III randomized, open-label MITO 35b study, a project of the MITO-MANGO groups

Background

Poly (ADP-ribose) polymerase inhibitors have transformed the management landscape for patients with ovarian cancer, demonstrating remarkable improvements in progression-free survival and overall survival. Unfortunately, most relapses are due to an acquired mechanism of resistance to these agents. We hypothesize that secondary cytoreductive surgery, removing resistant clones, might help to overcome the development of resistance to poly (ADP-ribose) polymerase inhibitors, prolonging their therapeutic effect.

Primary Objective

To determine the efficacy of olaparib beyond progression compared with standard platinum-based chemotherapy in patients with recurrent ovarian cancer progressed during or after poly (ADP-ribose) polymerase inhibitor maintenance therapy after secondary cytoreductive surgery.

Study Hypothesis

Olaparib administered beyond progression is more effective in increasing progression-free survival and progression-free survival 2 compared with second-line platinum-based chemotherapy in patients after secondary cytoreductive surgery.

Trial Design

Phase III, randomized, open-label, multicenter trial. Eligible patients will be randomized in a 1:1 ratio to receive olaparib or platinum-based chemotherapy of the investigator’s choice.

Major Eligibility Criteria

Eligible patients must have high-grade serous or endometrioid ovarian cancer progressed during or after first-line poly (ADP-ribose) polymerase inhibitor maintenance therapy and must have undergone secondary cytoreductive surgery.

Primary Endpoint

The dual primary endpoints will include progression-free survival and progression-free survival 2. Progression-free survival is defined by the investigator using Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 as the time between randomization and progression or death from any cause. Progression-free survival 2 is defined by the investigator using RECIST version 1.1 as the time frame from randomization to the second progression or death from any cause after subsequent treatment.

Sample Size

Approximately 200 patients will be enrolled in this study.

Estimated Dates for Completing Accrual and Presenting Results

Enrollment will be completed in 2024. Results will be presented in 2026.

Trial Registration

EudraCT 2021-000245-41 NCT05255471