Efficacy and Safety of Re-Challenging PD-1 Inhibitors in Second-Line Treatment in Metastatic Nasopharyngeal Carcinoma Previously Treated with Chemotherapy and PD-1 Inhibitors

Weixin Bei,1,2,* Shuhui Dong,1,2,* Guoying Liu,1,3,4,* Lanfeng Lin,2,5,* Yaofei Jiang,1,2 Nian Lu,1,2 Wangzhong Li,1,2 Hu Liang,1,2 Yanqun Xiang,1,2 Weixiong Xia1,2 1Department of Nasopharyngeal Carcinoma, Sun Yat-Sen University Cancer Center, Guangzhou, People’s Republic of China; 2State Key Laboratory of Oncology in South China, Guangdong Key Laboratory of Nasopharyngeal Carcinoma Diagnosis and Therapy, Guangdong Provincial Clinical Research Center for Cancer, Sun Yat-sen University Cancer Center, Guangzhou, People’s Republic of China; 3Guangdong Provincial Key Laboratory of Malignant Tumor Epigenetics and Gene Regulation, Medical Research Center, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, People’s Republic of China; 4Department of Radiation Oncology, Sun Yat-Sen Memorial Hospital, Sun Yat-Sen University, Guangzhou, People’s Republic of China; 5Department of Radiation Oncology, Sun Yat-Sen University Cancer Center, Guangzhou, People’s Republic of China*These authors contributed equally to this workCorrespondence: Yanqun Xiang; Weixiong Xia, Department of Nasopharyngeal Carcinoma, Sun Yat-sen University Cancer Center, 651 Dongfeng Road East, Guangzhou, 510060, People’s Republic of China, Tel +86-20-87343643, Fax +86-20-87343392, Email xiangyq@sysucc.org.cn; xiawx@sysucc.org.cnBackground: We aim to evaluate the efficacy and safety of anti-PD1 rechallenge in combination with chemotherapy in patients with metastatic nasopharyngeal carcinoma (mNPC) who have progressed on prior anti-PD1 therapy.Patients and Methods: We enrolled patients with mNPC who received chemotherapy combined with PD-1 immune-checkpoint inhibitors (ICIs) or chemotherapy alone after prior progression of anti-PD1 therapy. The primary endpoint was progress-free survival (PFS), and the secondary endpoints included overall survival (OS), disease control rate (DCR) and objective response rate (ORR).Results: A total of 96 patients were eligible between January 2015 and December 2020. Thirty-seven (38.5%) were in the PD-1 ICIs re-challenge group, while the remaining 59 patients (61.5%) were in the chemotherapy group. The ORR and DCR of PD-1 ICIs group and chemotherapy group were 37.8% vs 23.7% and 86.5% vs.74.5%, respectively. After a median follow-up period of 21.1 months (IQR 16.1– 28.7), the log-rank analysis demonstrated a significantly improved PFS in the PD-1 ICIs re-challenge group compared to the chemotherapy group (8.4 months [95% CI 4.3– 14.0] vs 5.0 months [95% CI 2.8– 7.2], P = 0.03). However, no significant difference in OS was observed between the two groups (28.3 vs 24.1 months, P = 0.09). The two groups had similar adverse reactions, but the incidence of grade 3 or 4 thrombocytopenia was significantly higher in the PD-1 ICIs re-challenge group (18.9% vs 3.4%, P = 0.025).Conclusion: mNPC patients who progressed from prior anti-PD1 therapy could benefit from the anti-PD1 rechallenge in combination with chemotherapy. However, further validation is needed.Keywords: metastatic nasopharyngeal carcinoma, chemotherapy, PD-1 immune checkpoint inhibitors, second-line treatment strategies