890P - Stereotactic body radiation therapy combined with chemotherapy and tislelizumab in metastatic nasopharyngeal carcinoma: A prospective, single-arm, phase II study

Background

There is an unmet need for more effective treatments in metastatic nasopharyngeal carcinoma (NPC) after chemo- and immune-therapy. The study aims to evaluate the outcomes of stereotactic body radiation therapy (SBRT) combined with chemotherapy and tislelizumab in treatment of metastatic NPC.

Methods

This is a single-centre, open-label, single-arm, phase II trial (NCT05652192). Patients(pts) should have at least one lesion eligible for SBRT (GTV 50Gy/5f). Then they received gemcitabine (1000 mg/m², d1/8) or nab-paclitaxel (240 mg/m², d1), cisplatin (80 mg/m², d1), tislelizumab (200 mg, d1) every 3 weeks for four to six cycles. Tislelizumab was administrated on Day1 every 3 weeks until disease progression (PD), intolerable toxicity, up to 35 cycles (two years), death, or withdrawal of consent. The primary endpoint was progression-free survival (PFS). The secondary endpoint is objective response rate (ORR) per RECIST 1.1 and safety/tolerability per CTCAE v5.0 criteria.

Results

Between Oct 2022 and Jan 2024, 36 pts were enrolled (median age: 52 years old, range:29-72; male: 80.6%). At the data cutoff date on January 31, 2024, 47 metastatic leisions of 28 patients were eligible for the evaluation of tumor response. 97.9% of the lesions (46 of 47) had a response with complete response 91.5%(n=43) and partial response 6.4% (n=3). one patient was evaluated as stable disease. Grade 3-4 adverse reactions occurred in 11.1% patients (4 of 36 patients) and no fatal adverse events occurred.

Conclusions

This preliminary analysis indicated that metastatic NPC patients could get high response from metastases-directed SBRT in combination with tislelizumab. Ongoing analysis of predictive biomarker on efficacy and safety will be available in the future meeting.

Clinical trial identification

NCT05652192.

Editorial acknowledgement

Funding

Has not received any funding.

Disclosure

All authors have declared no conflicts of interest.