Abstract 801P
Background
Between 17 to 25% of recurrent or metastatic endometrial carcinoma (EC) are MSI-H which results in improved response to immune checkpoint inhibitors (ICI). However, little is known regarding chemotherapy sensitivity in MSI-H EC, especially response to first-line platinum-based treatment.
Methods
We performed an academic multicentric retrospective study to determine the response to 1st line platinum based chemotherapy in MSI-H EC patients. Main endpoints were objective response rate (oRR) and disease control rate (DCR) at 6 months. Progression-free survival (PFS) and overall survival (OS) were estimated by the Kaplan-Meier method.
Results
Overall, 97 patients with advanced or recurrent MSI-H EC not eligible for curative local treatment from 8 centers were identified: 78 patients treated with 1st line platinum-based chemotherapy in metastatic setting were selected. Patients treated with other 1st line as chemotherapy, hormonal or / immune-therapy were excluded. Overall, 69 (88.4%) received carboplatin plus paclitaxel and 9 (11.5%) doublet platinum chemotherapy with doxorubicin pegylated or gemcitabine or carboplatin as monotherapy. Median age was 62 (42-90) years. Histology was endometrioid in 88% (69/78), serous 5.7% (4/78) or mixed 4% (3/78); 52% of patients had received prior adjuvant radiotherapy, but only 17% adjuvant platinum. ORR and DCR with 1st line platinum based chemotherapy were 50% and 68%, respectively. With a median follow up of 2.9 years (min: 0.04; max 11.3), median PFS and OS was 7.8 months (95% CI: 6.0-9.0) and 3.8 years (95% CI: 3.0-NE), respectively. Overall, 47 pts received ICIs post-platinum in second-line (n=31) or beyond (n=18). Median PFS and OS under ICI were 10.7 months (95% CI: 6.5, NE) and 2.7 years (95% CI: 1.2, NE) respectively.
Conclusions
The ORR and PFS in metastatic MSI-H EC receiving a 1st line platinum chemotherapy was reported for the 1st time. Platinum based chemotherapy efficacy in first-line for metastatic MSI-H EC seems consistent with efficacy reported in an all comers metastatic EC population. Whether ICI may improve outcomes in 1st line for MSI-H EC is under investigation and merit further studies.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Has not received any funding.
Disclosure
E. Colomba: Financial Interests, Personal, Invited Speaker: BMS; Financial Interests, Personal, Advisory Board: Ipsen; Financial Interests, Personal, Advisory Board: MSD; Financial Interests, Personal, Advisory Board: Pfizer; Financial Interests, Personal, Advisory Board: GSK; Financial Interests, Personal, Advisory Board: Tesaro. I.L. Ray-Coquard: Financial Interests, Personal, Invited Speaker: MSD; Financial Interests, Personal, Invited Speaker: Clovis; Financial Interests, Personal, Advisory Board: Tesaro; Financial Interests, Personal, Invited Speaker: GSK. F. Joly: Financial Interests, Personal, Advisory Board: MSD; Financial Interests, Personal, Invited Speaker: Tesaro. P. Pautier: Financial Interests, Personal, Invited Speaker: Tesaro; Financial Interests, Personal, Advisory Board: GSK; Financial Interests, Institutional, Principal Investigator: MSD. J. Frenel: Financial Interests, Personal, Invited Speaker: Amgen; Financial Interests, Personal, Invited Speaker: AstraZeneca; Financial Interests, Personal, Invited Speaker: Daiichi; Financial Interests, Personal, Invited Speaker: GSK; Financial Interests, Personal, Advisory Board: Clovis; Financial Interests, Personal, Advisory Board: MSD; Financial Interests, Personal, Advisory Board: Lilly. A. Leary: Financial Interests, Institutional, Invited Speaker: GSK; Financial Interests, Institutional, Invited Speaker: MSD; Financial Interests, Institutional, Invited Speaker: Tesaro; Financial Interests, Institutional, Invited Speaker: Roche; Financial Interests, Institutional, Principal Investigator: BMS. All other authors have declared no conflicts of interest.