Abstract 824P
Background
PARPi maintenance after Pt-based chemotherapy (CT) significantly improves progression-free survival (PFS) and PFS to subsequent (ssq) chemotherapy (PFS2) in relapsed HGSOC. However, crossed mechanisms of action and resistance between PARPi and Pt cast doubts on the benefit from ssq Pt after PARPi progression. We provide RWD on this issue.
Methods
We included HGSOC p treated with ssq CT after progression to maintenance PARPi until 31st Dec 2019 in 3 large hospitals. Endpoints were overall response rate (ORR), median (m) PFS and overall survival (mOS) to ssq Pt after PARPi. Analysis were also performed according to 3 populations: p who received ssq non-Pt CT, p with Pt-free interval (PFI) 6-12 months (mo) and p with PFI >12 mo.
Results
54 p were identified (57.4 % BRCAmut). 4p (7.4%) received PARPi after 1st line CT, 25 (46.3%) after 2nd line, and 25 (46.3%) after ≥3rd line. 34p (63%) received olaparib and 20 (37%) niraparib. mPFS of PARPi as maintenance in the recurrent setting was 7.5 mo and PFS2 15.4 mo. Distribution of ssq CT schemes and their best responses are shown in the table. ORR to ssq Pt was 33.3%, and progression disease (PD) 28.6%. ORR in p who received ssq Pt-free CT, p with PFI 6-12 mo, and p with PFI >12 mo were 28.6%, 22.7% and 45%, respectively. The 4 identified complete responses (CR) occurred among BRCAmut p receiving PARPi in the recurrent setting and PFI>12. Survival endpoints of ssq CT are shown in the table. mPFS and mOS were significantly longer in the PFI >12 subgroup versus the others. Survival did not change when excluding the 4p who received PARPi as 1st line (Table). Table: 824P
| Non Pt-CTN=9 | Pt-CT | p | ||
| PFI 6-12 mo N=24 | PFI >12 mo N=21 | |||
| BRCAmut (n, %) | 5 (55.6) | 12 (50) | 14 (66.7) | 0.055 |
| From ssq CT after PARPi: | ||||
| Best responses (n, %)* | 0.010 | |||
| CR | 0 | 0 | 4 (20) | |
| Partial response | 2 (28.6) | 5 (22.7) | 5 (25) | |
| Stable disease | 2 (28.6) | 6 (27.3) | 10 (50) | |
| PD | 3 (42.9) | 11 (50.0) | 1 (5) | |
| mPFS (mo, 95%CI) | 5.1(3.2-) | 5.1 (4.0-9.0) | 9.4 (6.7-14.0) | 0.055 |
| mOS (mo, 95%CI) | 6.8 (3.12-) | 14.2 (9.4-) | 28.2 (11.9-) | 0.018 |
*Evaluable p (n=49).
Conclusions
Higher benefit from ssq Pt after PARPi was observed in the PFI>12 subgroup. Benefit from ssq Pt after PARPi in the PFI 6-12 subgroup was similar to benefit from CT in the non-Pt subgroup. The role of ssq Pt after PARPi in the PFI 6-12 subgroup warrants further research.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
A. Plaja Salarich: Travel/Accommodation/Expenses: Angelini; Travel/Accommodation/Expenses: Roche. B. Pardo Burdalo: Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Roche; Speaker Bureau/Expert testimony: AstraZeneca; Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: MSD; Travel/Accommodation/Expenses: GSK. M. Gil-Martin: Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Roche; Speaker Bureau/Expert testimony: AstraZeneca; Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: PharmaMar; Travel/Accommodation/Expenses: MSD. J.M. Piulats: Advisory/Consultancy: Clovis; Advisory/Consultancy, Research grant/Funding (institution): AstraZeneca; Advisory/Consultancy, Research grant/Funding (institution): MSD; Advisory/Consultancy, Research grant/Funding (institution): BeiGene. C. Fina Planas: Travel/Accommodation/Expenses: Roche; Travel/Accommodation/Expenses: MSD; Travel/Accommodation/Expenses: Pfizer; Travel/Accommodation/Expenses: Bristol-Myers. M.P. Barretina Ginesta: Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: AstraZeneca; Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: GSK; Advisory/Consultancy, Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: Roche; Speaker Bureau/Expert testimony, Travel/Accommodation/Expenses: PharmaMar; Advisory/Consultancy, Speaker Bureau/Expert testimony: Clovis Oncology. M. Romeo Marin: Advisory/Consultancy: AstraZeneca; Advisory/Consultancy: Tesaro; Travel/Accommodation/Expenses: Pfizer. All other authors have declared no conflicts of interest.