290MO - Efficacy and safety of topical sintilimab administration in conjunction with CRT and Californium-252 neutron brachytherapy in first-line advanced gynecological squamous cell carcinoma patients

Background

Exploring enhanced tumor control, we studied concurrent chemoradiotherapy (CRT) with PD-1 blockade, including Californium-252 neutron brachytherapy for advanced gynecological tumors. This trial investigates the combination of local sintilimab injection with this approach to augment treatment outcomes in first-line advanced gynecological squamous cell carcinoma patients.

Methods

A phase II trial was conducted on these patients who underwent CRT and Californium-252 brachytherapy. Concurrently, they received local sintilimab injections (100mg Q3W, 4 cycles). During each procedure, 4-6 hysteroscopy-guided injections were administered to the cervix. Primary endpoints: Objective Response Rate (ORR) and Progression-Free Survival (PFS). Secondary objectives: Duration of Response (DOR), Disease Control Rate (DCR), Overall Survival (OS), and Adverse Events (CTCAE 5.0).

Results

By June 30, 2023, 20 patients were included (median age: 57.5; 19 with cervical and 1 with vaginal carcinoma). With a median follow-up of 24 months (39-76 months range), ORR reached 100%, and PFS is still undetermined. Treatment AEs were seen in 15% (3/20) of patients, grade 3 AEs in 5% (1/20). All AEs were thyroid dysfunctions (2 at grade 2, 1 at grade 3). One death occurred due to cardiovascular-related heart failure.

Conclusions

This is the first evaluation of combined CRT, Californium-252 brachytherapy, and local sintilimab for gynecological tumors. Preliminary results highlight substantial anti-tumor potential and a favorable safety profile. Further research with a larger cohort is warranted.

Clinical trial identification

CHICTR2300074868.

Editorial acknowledgement

Legal entity responsible for the study

The authors.

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.