Introduction/Background The prognosis of women with gynaecologic malignancies which progress after standard oncological treatment remains poor. While immune checkpoint inhibitors targeting the PD1/PDL1 pathway have provided durable responses in various tumour types, their use in gynaecologic oncology is an area of active research.

Methodology We retrospectively analysed data from women with advanced or metastatic ovarian carcinoma, cervical cancer or endometrial cancer treated within a compassionate program with nivolumab or pembrolizumab between March 2015 and January 2019 at Lausanne University Hospital. The efficacy endpoint was best overall response rate by RECIST 1.1.

Results Patients had a mean age of 63 years (range 46–79 years). We included in total 11 patients, with high grade serous ovarian adenocarcinoma (n=4), squamous cell carcinoma of the cervix (n=3), cervical adenocarcinoma (n=1), basal adenoid cervical carcinoma (n=1) endometroid endometrial cancer (n=1) and serous endometrial cancer (n=1). All patients received nivolumab 240 mg every 2 weeks, except one who received pembrolizumab 200 mg every 3 weeks and 20 mg lenvatinib daily. Ovarian cancer patients were treated in fourth line or beyond, cervical cancer and endometrial cancer patients in third line. The mean number of therapy cycles was 7 for ovarian cancer, 9 for cervical cancer and 5 for endometrial cancer.

The best overall response was partial response in cervical cancer (n=3) and ovarian cancer (n=1). Stable disease was found in one patient with cervical and ovarian cancer, respectively. Endometrial cancer patients did not respond.

Conclusion In our small cohort of unselected gynaecologic cancer patients treated with anti-PD1 antibodies after failure of standard of care treatments, response rates were highest among cervical cancer patients. Differences in tumour immunogenicity such as PD-L1 expression, human papilloma virus infection, microsatellite instability and POLE mutations may affect response rates.

Disclosure Nothing to disclose.