Abstract 715P
Background
In the treatment of lung cancer with immune checkpoint inhibitors (ICI), there is a need for predictive therapeutic biomarkers that can be measured noninvasively. Various autoantibodies have been detected in cancer patient sera, among which anti-p53 antibodies are associated with p53 gene mutations. p53 gene mutations have been reported to be associated with efficacy of ICI, however, it is unclear whether anti-p53 antibodies affect the antitumor effect of ICI.
Methods
Participants were patients with advanced non-small cell lung cancer who received ICI at our hospital from November 2018 to May 2022. Blood samples were obtained before and after treatment with ICI and serum anti-p53 antibody levels were measured. The relationship between serum anti-p53 antibody and treatment response (response, progression-free survival, and overall survival) to ICI was investigated.
Results
A total of 166 patients were enrolled. Median age was 69.4 (range, 43-90), 30.1% (50/166) were females. PD-L1 TPS ≥50%/1-49%/<1%/unknown included 54 (32.5%)/45 (27.1%)/34 (20.5%)/33 (19.9%), respectively. Serum anti-p53 antibody positive rate (p53+) before treatment was 17.5% (29/166). No significant differences in patient characteristics between p53+ and p53- groups. Patients in the p53+ group tended to have shorter PFS (HR 1.37, 95%CI 0.83-2.3, p=0.215) than those in the p53- group. 16 patients in the p53+ group had a decrease in p53 antibody levels after treatment with ICI ± chemotherapy. Serum anti-p53 antibody levels varied with treatment with ICI ± chemotherapy. Patients with decrease in p53 antibody levels after treatment had significantly longer PFS (HR 5.03, 95%CI 1.92-13.24, p=0.001) than those with not decrease.
Conclusions
We believe serum p53 antibody could be useful as a predictor of therapeutic efficacy of ICI for advanced non-small cell lung cancer.
Clinical trial identification
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.