Thyroid irAEs Common With PD-L1 Inhibitors

The following article features coverage from the American Thyroid Association (ATA) 2018 meeting. Click here to read more of Cancer Therapy Advisor‘s conference coverage.

Thyroid immune-related adverse events (irAEs) are common among patients treated with anti–PD-L1 antibodies, according to a retrospective study presented at the 88th Annual Meeting of the American Thyroid Association in Washington, D.C.¹

PD-L1 inhibitors are associated with an increased risk of developing irAEs. The purpose of this study was to characterize thyroid irAEs to improve detection and management strategies.

The retrospective cohort study included 91 patients who received an anti–PD-L1 inhibitor between 2016 and 2018 at the Mayo Clinic. The median age of the cohort was 68, 52% were male, and the median follow-up was 5 months.

irAEs developed in 46% of patients, of which, 25% were related to the thyroid. Thyroid irAEs included acute thyroiditis (22%), new-onset hypothyroidism (61%), and worsening hypothyroidism (17%). Thyroid irAEs developed after 2 doses of the PD-L1 inhibitor, with a median time to development of 1.4 months.

Patients were managed by observation (52%) or through treatment with  levothyroxine (48%).

At baseline, elevated levels of thyroperoxidase (TPO) antibodies was present in 31% of patients, with 2 patients developing a thyroid irAE. Most patients who developed a thyroid irAE demonstrated a diffusely elevated FDG thyroid uptake on PET (P = .001).

Patients who developed a thyroid irAE had an overall survival of 12 months compared with 9.9 months among patients who did not experience a thyroid irAE (P = .03). The authors note, however, that additional studies are needed to determine if a thyroid irAE is a marker of antitumor response.

The authors concluded that thyroiditis is the most common endocrine irAE associated with PD-L1 inhibition. They stated that “diffuse thyroid uptake on FDG-PET [fluorodeoxyglucose-positron emission tomography] scan, but not elevated TPO antibodies, appears to identify patients at risk for thyroiditis/hypothyroidism.”

Read more of Cancer Therapy Advisor‘s coverage of the ATA 2018 meeting by visiting the conference page.

Reference

1. Kotwal A, Kottschade L, Ryder M. Programmed cell death protein ligand-1 inhibitor-associated thyroiditis: a retrospective comprehensive review at Mayo Clinic. Presented at: the 88th Annual Meeting of the American Thyroid Association; Washington, D.C.: October 3-7, 2018. Abstract clinical oral 12.