Safety and efficacy of immune checkpoint inhibitors in non-small cell lung cancer patients with preexisting antinuclear antibodies: a retrospective cohort study

Background: Antinuclear antibodies (ANAs) predicting the safety and efficacy of patients with advanced non-small cell lung cancer (NSCLC) treated with immune checkpoint inhibitors (ICIs) are still a matter of debate considering previous studies showed quite different results based on different ANA cut-off values. Thus, we investigated the associations between different ANA titers and the safety and efficacy of ICIs. Moreover, we also briefly discussed the effects of anti-thyroglobulin (ATG) and anti-thyroid peroxidase (ATPO) on the safety of ICIs. Methods: A total of 159 Chinese patients confirmed to have locally-advanced or metastatic NSCLC given ICIs or chemoimmunotherapy in Peking Union Medical College Hospital from January 2015 to December 2020 were analyzed retrospectively and were followed up until December 2020 or death or loss to followup. Patients' characteristics were retrieved from medical records. ANAs were detected by the indirect immunofluorescence assay, ATG and ATPO by the electrochemiluminescence immunoassay. The severity of immune-related adverse events (irAEs) was graded according to the Common Terminology Criteria for Adverse Events (CTCAE 5.0) and the efficacy was evaluated by the Response Evaluation Criteria in Solid Tumors (RECIST 1.1). Results: The incidence of irAEs, median progression-free survival (mPFS) of the ANA negative and positive groups were 26.0% vs. 31.4% (P=0.457), 17.7 vs. 10 months (P=0.603) for the cut-off value of 1:80; 26.2% vs. 33.9% (P=0.305), 11.9 vs. 10.6 months (P=0.957) for 1:160; and 25.9% vs. 45.8% (P=0.047), and 11.9 vs. 7.7 months (P=0.471) for 1:320, separately. Besides, ANA titer >= 1:320 was associated with irAEs [odds ratio (OR) =4.9, 95% confidence interval (CI): 1.45-16.52, P=0.01] and the incidence of adverse skin reactions differed greatly between the negative and positive groups (9.7% vs. 32%, P=0.003). Moreover, a total of 52 out of 159 patients were tested for ATG and ATPO. 46 patients were negative and 6 were positive, with the incidence of abnormal thyroid function being 4.3% vs. 50% (P=0.005), respectively. Conclusions: Preexisting ANAs may not correlate with the clinical benefit of immunotherapy in patients with NSCLC but may be associated with adverse skin reactions. Besides, ATG or ATPO has the potential to predict thyroid dysfunction.