Management of Thyrotoxicosis Induced by PD1 or PD-L1 Blockade

Clinical significance of thyroid autoantibodies in differential diagnosis and predicting the course of programmed cell death protein-1 inhibitor-induced thyroid dysfunction

BACKGROUND

Thyroid immune-related thyrotoxicosis is one of the most common adverse effects in patients treated with programmed cell death protein-1 (PD-1) inhibitors. We investigated the significance of levels of serum anti-thyroglobulin antibodies (TgAbs), anti-thyroid peroxidase antibodies (TPOAbs), and TSH receptor antibodies (TRAbs) in the identification of anti-PD-1-induced thyroid thyrotoxicosis.

METHODS

We divided 161 patients with thyroid dysfunction who received PD-1 inhibitors at our hospital between January 2022 and June 2024 into three groups: primary hypothyroidism group, primary hyperthyroidism group, and destructive thyroiditis group. The characteristics of the three groups were determined, and the positivity rates of serum TgAbs, TPOAbs, and TRAbs were assessed. An additional 42 patients diagnosed with Hashimoto's thyroiditis were selected as the control group for PD-1 inhibition-induced destructive thyroiditis. Age, sex, and time of transition from thyrotoxicosis to hypothyroidism in the two groups were compared.

RESULTS

In the primary hypothyroidism group, only one case was TPOAbs-positive (1/1%). In the destructive thyroiditis group, the positivity rate for TPOAbs or TgAbs was 92.9%, and TPOAbs and TgAbs were negative in the primary hyperthyroidism group. TRAbs were undetectable in all three groups. There were statistically significant differences in age, sex, and time from thyrotoxicosis to hypothyroidism in the PD-1 induced destructive thyroiditis and Hashimoto's thyroiditis groups.

CONCLUSIONS

In patients with thyrotoxicosis caused by PD-1 inhibitors, serum TgAb and TPOAb levels can be used to distinguish between primary hyperthyroidism and destructive thyroiditis. This study provides insights into novel treatment targets and effective management strategies for PD-1-induced thyrotoxicosis.

The Price of Success: Immune-Related Adverse Events from Immunotherapy in Lung Cancer

Cancer immunotherapy has the goal of enhancing a patient’s intrinsic immune processes in order to mount a successful immune response against tumor cells. Cancer cells actively employ tactics to evade, delay, alter, or attenuate the anti-tumor immune response. Immune checkpoint inhibitors (ICIs) modulate endogenous regulatory immune mechanisms to enhance immune system activation, and have become the mainstay of therapy in many cancer types. This activation occurs broadly and as a result, activation is supraphysiologic and relatively non-specific, which can lead to immune-related adverse events (irAEs), the frequency of which depends on the patient, the cancer type, and the specific ICI antibody. Careful assessment of patients for irAEs through history taking, physical exam, and routine laboratory assessments are key to identifying irAEs at early stages, when they can potentially be managed more easily and before progressing to higher grades or more serious effects. Generally, most patients with low grade irAEs are eligible for re-challenge with ICIs, and the use of corticosteroids to address an irAE is not associated with poorer patient outcomes. This paper reviews immune checkpoint inhibitors (ICIs) including their mechanisms of action, usage, associated irAEs, and their management.