A Systematic Review and Meta-Analysis of Endocrine-Related Adverse Events Associated with Immune Checkpoint Inhibitors

Monoclonal antibodies targeting cytotoxic T-lymphocyte antigen-4 (CTLA-4), programed cell death 1 (PD-1), or its ligand (PD-L1) have become the mainstay for advanced malignancies. The incidence of endocrine adverse events provoked by these immune checkpoint inhibitors (ICI) is based on data from randomized controlled trials, which have their drawbacks. PubMed was searched through August 22nd, 2017, by 2 reviewers independently (J.d.F. and C.E.A.). Early phase I/II, phase III experimental trials, prospective and retrospective observational studies were included. The weighted incidence and risk ratio were estimated for hypophysitis, primary thyroid disease, primary adrenal insufficiency, and diabetes mellitus. Their management is discussed in a systematic review. A total of 101 studies involving 19 922 patients were included. Ipilimumab-treated patients experienced hypophysitis in 5.6% (95% CI, 3.9-8.1), which was higher than nivolumab (0.5%; 95% CI, 0.2-1.2) and pembrolizumab (1.1%; 95% CI, 0.5-2.6). PD-1/PD-L1 inhibitors had a higher incidence of thyroid dysfunction - particularly hypothyroidism (nivolumab, 8.0%; 95% CI, 6.4-9.8; pembrolizumab, 8.5%; 95% CI, 7.5-9.7; PD-L1, 5.5%; 95% CI, 4.4-6.8; ipilimumab, 3.8%; 95% CI, 2.6-5.5). Combination therapy was associated with a high incidence of hypothyroidism (10.2-16.4%), hyperthyroidism (9.4-10.4%), hypophysitis (8.8-10.5%), and primary adrenal insufficiency (5.2-7.6%). Diabetes mellitus and primary adrenal insufficiency were less frequent findings on monotherapy. Our meta-analysis shows a high incidence of endocrine adverse events provoked by single agent checkpoint blockade, further reinforced by combined treatment.

Successful Pretreatment Using Plasma Exchange before Thyroidectomy in a Patient with Amiodarone-Induced Thyrotoxicosis

INTRODUCTION

Amiodarone, used for the management of tachyarrhythmias, is associated with both hypothyroidism and thyrotoxicosis. Total thyroidectomy is an effective procedure for promptly reducing circulating thyroid hormone levels. It has been proposed in patients who have severe amiodarone-induced thyrotoxicosis (AIT) or are refractory to medical therapy, or when such therapy is contraindicated. Therapeutic plasma exchange (TPE) may be considered as a pretreatment for restoring a euthyroid state preoperatively, thereby reducing a patient's symptoms and the potential perioperative risk associated with thyrotoxicosis.

CASE REPORT

We describe the case of a 62-year-old man with type 2 AIT who presented with severe unremitting thyrotoxicosis after 8 weeks of medical therapy with glucocorticosteroids, thiamazole, and potassium perchlorate. Given the severity of his presentation, a total thyroidectomy was indicated. TPE was performed preoperatively and was successful in rapidly restoring euthyroidism. This dramatically improved the patient's symptoms which had been suggestive of ischemic heart disease. Subsequently, the patient underwent total thyroidectomy under general anesthesia without any major complications.

CONCLUSION

TPE is successful in rapidly restoring a clinical and biochemical euthyroid state, and may be used to decrease the perioperative risks associated with thyroidectomy in patients with life-threatening thyrotoxicosis or in cases refractory to medical treatment.

Incidence of Thyroid-Related Adverse Events in Melanoma Patients Treated With Pembrolizumab

CONTEXT

Immune checkpoint blockade is associated with endocrine-related adverse events. Thyroid dysfunction during pembrolizumab therapy, an anti-programmed cell death 1 (PD-1) receptor monoclonal antibody, remains to be fully characterized.

OBJECTIVE

To assess the incidence and characteristics of pembrolizumab-associated thyroid dysfunction.

DESIGN AND SETTING

Thyroid function was monitored prospectively in melanoma patients who initiated pembrolizumab within an expanded access program at a referral oncology center. 18Fluorodeoxyglucose uptake on positron emission tomography/computed tomography (18FDG-PET/CT) was reviewed in cases compatible with inflammatory thyroiditis.

PATIENTS

Ninety-nine patients with advanced melanoma (age, 26.3-93.6 years; 63.6% females) who received at least one administration of pembrolizumab.

MAIN OUTCOME MEASURES

Patient characteristics, thyroid function (TSH, free T4), thyroid autoantibodies, and 18FDG-PET/CT.

RESULTS

Eighteen adverse events of thyroid dysfunction were observed in 17 patients. Thyrotoxicosis occurred in 12 patients, of which nine evolved to hypothyroidism. Isolated hypothyroidism was present in six patients. Levothyroxine therapy was required in 10 of 15 hypothyroid patients. Thyroid autoantibodies were elevated during thyroid dysfunction in four of 10 cases. Diffuse increased 18FDG uptake by the thyroid gland was observed in all seven thyrotoxic patients who progressed to hypothyroidism.

CONCLUSIONS

Thyroid dysfunction is common in melanoma patients treated with pembrolizumab. Hypothyroidism and thyrotoxicosis related to inflammatory thyroiditis are the most frequent presentations. Serial measurements of thyroid function tests are indicated during anti-PD-1 monoclonal antibody therapy. Thyrotoxicosis compatible with inflammatory thyroiditis was associated with diffuse increased 18FDG uptake by the thyroid gland. The prospective role of thyroid autoantibodies should be further investigated, together with the histopathological correlates.