Nimotuzumab in combination with radiotherapy for elderly patients with locally advanced cervical squamous cell carcinoma: Results from a prospective, multicenter, open-label, single-arm trial.

5527 Background: Locally advanced cervical squamous cell carcinoma (LACSCC) is associated with poor survival, and elderly patients generally have fewer treatment options due to chemotherapy intolerance. Nimotuzumab is a humanized monoclonal antibody that has demonstrated therapeutic activity in many tumors. We conducted a single-arm trial to investigate the efficacy and safety of combining nimotuzumab and radiotherapy for elderly patients with LACSCC. Methods: In this prospective, multicenter, open-label, and single-arm trial, patients with LACSCC were registered (NCT04976478) and enrolled from Nov 2021 to Jan 2023. All patients were ≥ 65 years old, had ECOG of 0-2, histological diagnosis of cervical squamous cell carcinoma, clinical stage IB3-IVA (FIGO 2018), intolerant to chemotherapy, or refused chemotherapy. The regimen was nimotuzumab (200 mg once in a week for 6 weeks) combined with radiotherapy. The radiotherapy scheme contained intensity-modulated radiotherapy (IMRT)/volumetric intensity-modulated arc therapy (VMAT) with pelvic/extended field irradiation (45-50.4Gy, 1.8-2.0Gy/f, 25-28f), and brachytherapy (HR-CTV D90, 80-85Gy), of which brachytherapy plus external beam radiotherapy was completed in 8 weeks. The primary endpoints were overall survival (OS) and disease-free survival (DFS). Other assessed endpoints were objective response rate (ORR), disease control rate (DCR) and complete response rate (CRR). All adverse events were monitored and recorded. Results: As of Jan 2023, 119 elderly patients have been enrolled and all patients were included in the efficacy and safety analysis. The median follow-up was 16.16 months (95% CI: 13.14-17.45). Nimotuzumab combined with radiotherapy resulted in favorable OS (1 year-OS: 96.03%, 95% CI: 89.75-98.50; 2 year-OS: 90.21%, 95% CI: 78.98-95.60), and DFS (1 year-DFS: 85.71%, 95% CI: 76.98-91.31; 2 year-DFS: 78.31%, 95% CI: 66.67-86.29). The ORR was 89.92%, DCR was 93.28%, and CRR was 52.94%. A total of seven patients died, of which three were due to disease progression and two were of unknown causes. The most common Grade 3-5 adverse events (AEs) mainly included leukopenia (3.36%), anemia (2.52%), and neutropenia (1.68%). None of the patients developed severe AEs or deaths. So far, this trial is still ongoing. Conclusions: Among elderly LACSCC patients, adding nimotuzumab to radiotherapy indicated promising efficacy and appeared to have manageable toxicity. Nimotuzumab plus radiotherapy could represent a novel treatment strategy for this population. Clinical trial information: NCT04976478 .