Complete Response to PD-1 Inhibitor in Primary Hepatocellular Carcinoma Patients Post-Progression on Bi-Specific Antibody Conjugated CIK Cell Treatment: A Report of Two Cases

BACKGROUND: Programmed death receptor-1 (PD-1) immune checkpoint inhibitors (ICIs) have produced encouraging results in hepatocellular carcinoma (HCC) patients. Cytokine-induced killer (CIK) cells treatment can specifically identify tumor-associated antigens and has encouraging preliminary efficacy for HCC. This study reported two cases of HCC patients achieved complete response (CR) by anti-PD-1 antibody therapy post-progression on bi-specific antibody conjugated CIK immunotherapy. CASE PRESENTATION: Case one, a 75-year-old male, was diagnosed with the intrahepatic cholangiocarcinoma (ICC) in October 2017. After interventional, CIK, ablation and other comprehensive therapy, ICC was gradually cured. When new occurrence of HCC, he was treated with anti-PD-1 antibody therapy and achieved CR. Case two, a 65-year-old female, was diagnosed with HCC in July 2016. After progression on several ablation treatments, she received 8 cycles of CIK treatment and achieved stable disease (SD). After disease progressed on CIK treatment, she received 4 cycles of anti-PD-1 antibody therapy, finally achieved CR. CONCLUSION: Anti-PD-1 antibody therapy after prior progression on bi-specific antibody conjugated CIK immunotherapy may be efficacy and safety for HCC patients.