Of 91 patients who were treated with a PD-L1 inhibitor, the majority (86, ~95%) had received atezolizumab. The average age of the patients was 67.9 years, 47% were male, and nearly 2/3s of patients were being treated for primary lung cancer. Thyroid problems occurred in 23 subjects (25%); 61% developed hypothyroidism, 22% developed hyperthyroidism and 17% developed worsening of already existing hypothyroidism. Most patients developed the thyroid problem in about 6 weeks after starting the therapy.
On average, patients were followed for 6 months after the onset of the thyroid disease. During this time, 3 patients had spontaneous recovery.
After looking at mortality rate, the researchers found that a lower number of patients who developed thyroid disease died during the study period (43.5% of patients with a thyroid dysfunction versus 79.4% patients who did not developed thyroid disease).
WHAT ARE THE IMPLICATIONS OF THIS STUDY?
In summary, this study showed that 25% of patients who had received a PD-L1 inhibitor drug also developed autoimmune thyroid disease. Interestingly the survival rate of patients who developed this type of side effect was better compared to the rest.
As more immune checkpoint inhibitors enter the market for treatment of cancer, this and similar studies will be instrumental to improve our knowledge about them.
— Shirin Haddady, MD MPH