Thyroid dysfunction induced by immune checkpoint inhibitors is associated with a better progression-free survival and overall survival in non-small cell lung cancer: an original cohort study

Background The objective of this study was to investigate the association between the onset of TD and treatment efficacy in NSCLC patients who initiated anti-PD-1 blockade (Nivolumab(R)) and to assess the impact of TD severity and subtype on nivolumab efficacy. Materials and methods This study was performed at a referral oncology center between July 20, 2015 and June 30, 2018. Patients with histologically confirmed stage IIIB/IV NSCLC in progression after one or two lines of treatment and who initiated Nivolumab were included. Thyroid function (TSH +/- fT4, fT3) was monitored and patients were classified according to TD status [TD(+) versus TD(-)], severity [moderate thyroid dysfunction: TSH level between 0.1 and 0.4 or 4.0 and 10 mIU/L and severe thyroid dysfunction: TSH <= 0.1 or >= 10mUI/L) and subtype (isolated hypothyroidism, isolated hyperthyroidism and hyperthyroidism then hypothyroidism)]. Clinical endpoints were overall survival (OS) and progression-free survival (PFS). Results Among 194 eligible patients, 134 patients (median age, 63 yo; 70.1% male) were included. Forty (29.9%) patients were classified in TD(+) and had a longer OS of 29.8 months (95% CI 18.8-NR) versus 8.1 months (95% CI 5.5-11.5) in TD(-) group (p < 0.001). PFS was also longer (8.7 months (95% CI 5.3-15.1) in TD(+) versus 1.7 months (95% CI 1.6-1.9) in TD(-) group (p < 0.001). In Cox proportional hazards analysis, TD remained an independent predictive factor of OS/PFS. Severity and subtype of TD were not correlated with OS/PFS. Conclusions This study suggested that TD induced by Nivolumab appears to be an independent predictive factor of survival, irrespective of TD severity and subtype.