Category: Thyroid

Monitor: 12

12 - ATEZOLIZUMAB-INDUCED AUTOIMMUNE THYROIDITIS

Friday, Apr 26
11:30 AM – 12:00 PM

Objective :

Atezolizumab is an immune checkpoint inhibitor used in the treatment of metastatic non-small cell lung cancer (NSCLC) and bladder cancer. It has been associated with immune-related endocrinopathies (IrAEs), such as thyroid dysfunctions, hypophysitis, adrenal insufficiency, and type 1 diabetes mellitus. Thyroid dysfunction is expressed as hypothyroidism, hyperthyroidism, and thyroiditis, mostly described around week 12 after the start of therapy. Thyroid disorders have been more commonly reported with the PD1 inhibitors Nivolumab and Pembrolizumab.  


Methods : We report a case of thyroiditis with the anti-PD-L1 antibody, Atezolizumab.


Results :


Case Presentation: A 64-year-old man with stage 3A NSCLC status post right bilobectomy with metastases to lymph nodes was evaluated. 6 weeks after the initiation of Atezolizumab (1200mg IV x1, q 3 weeks) the patient was found to have TSH  0.0240 uIU/mL (0.55-4.78), Free T4 2.34 ng/dL (0.66-1.73), Total T3 176.10 ng/dL (60-181), Anti-TG igG 1618 U/mL (ref < 60), and Anti-TPO IgG 1612 U/mL (ref < 60). Physical exam showed a mildly enlarged non-tender and firm thyroid. Patient was started on low dose beta blocker. 12 weeks after initiation of Atezolizumab, labs revealed primary hypothyroidism with a TSH of 55.75 µIU/mL and a FT4 of 0.22 ng/dL. The pretreatment antibody levels were not available. Levothyroxine was started and the patient showed laboratory and clinical improvement.


Discussion :

Atezolizumab is a humanized kappa immunoglobulin(Ig) G1 monoclonal antibody. It acts as an immunomodulator by targeting human PD-L1 and inhibiting its interaction with its receptors, programmed death−1 (PD-1) which can provide inhibitory signals to T cells. IrAE are common and can include thyroiditis, primary and secondary hypothyroidism and hyperthyroidism. Autoimmune thyroiditis is the most common thyroiditis described in patients with NSCLC during treatment with immune checkpoints inhibitors. The clinical course of thyroiditis is characterized by a transient hyperthyroid phase of a destructive thyroiditis with progression to eventual overt, permanent hypothyroidism. The diagnosis of these cases is made difficult with symptoms that can mimic the progression of cancer, and underscores that early recognition and management can improve symptoms and is imperative. 


Conclusion : Immune checkpoint inhibitors have become new standard treatment for many different types of malignancies. Since the number of patients treated with Atezolizumab is expected to increase, this case should increase awareness of this form of thyroid dysfunction. It is important to recognize autoimmune thyroiditis as one of the important IrAEs.

SHORT URL FUNCTION-->

Jien Shim

Endocrinology Fellow
University of California, Los Angeles
Los Angeles, California

I am a second year fellow at UCLA. I am interested in general endocrinology.

Shalini Bhat

Assistant Professor of Medicine, David Geffen School of Medicine at UCLA
Division of Endocrinology, Diabetes and Hypertension, Department of Medicine, David Geffen School of Medicine at UCLA and VA Greater Los Angeles Healthcare Systems, Los Angeles, CA

Assistant Professor of Medicine, David Geffen School of Medicine at UCLA

Jien Shim

Endocrinology Fellow
University of California, Los Angeles
Los Angeles, California

I am a second year fellow at UCLA. I am interested in general endocrinology.