CTLA4 and hyperthyroidism: In particular, a meta-analysis of 28 studies, which included more than 7,500 patients, showed an incidence of hyperthyroidism and hypothyroidism, under combined anti-CTLA4/anti-PD1 treatment, of 8% and 13.2% versus 3.2% and 3.9% in the course of an anti-PD1 treatment, respectively (8).