Reversible hypopituitarism after interferonalfa therapy

Hypophysitis in the era of immune checkpoint inhibitors and immunoglobulin G4-related disease

INTRODUCTION

Hypophysitis is a rare disorder, defined as inflammation of the pituitary gland that may result in pituitary enlargement and varying anterior and posterior pituitary hormonal deficits. It involves different histopathological subtypes and variable etiologies, with considerable overlap between classification systems. Histopathology is the gold standard diagnostic approach.

AREAS COVERED

In this article, we will review the major histopathological subtypes of hypophysitis with a special focus on immunoglobulin G4 (IgG4)-related hypophysitis and immune checkpoint inhibitor-induced hypophysitis, given their recent appearance and increasing incidence. We will summarize the similarities and differences between the different subtypes as it relates to epidemiology, pathogenesis, presentation, diagnosis, and management.

EXPERT OPINION

Hypophysitis is a heterogeneous and wide term used to describe different, possibly distinct diseases often with poorly understood pathogenesis. It involves a wide range of subtypes with certain differences in incidence rates, pathogenesis, and management. Management usually focuses on relieving the mass effect symptoms and replacing the deficient pituitary hormones. Spontaneous recovery is possible but recurrence is not uncommon.

Hypophysitis: Evaluation and Management

Hypophysitis is the acute or chronic inflammation of the pituitary gland. The spectrum of hypophysitis has expanded in recent years with the addition of two histologic subtypes and recognition as a complication of treatment with immune checkpoint inhibitors. Despite the increased number of published cases, the pathogenesis of hypophysitis is poorly understood, and treatment strategies are diverse and controversial. The diagnosis of hypophysitis generally requires histopathologic confirmation. The presentation and clinical course of hypophysitis varies. Hypophysitis can resolve spontaneously, relapse may occur, and some cases can be refractory to treatment.

Immunotherapy and hypophysitis: clinical presentation, treatment, and biologic insights

INTRODUCTION

Advances in immunotherapy have transformed the management of metastatic melanoma and generated encouraging results in the treatment of other malignancies. Autoimmune side effects from these agents, termed immune-related adverse events (IRAEs), are diverse and can include multiple endocrinopathies. Ipilimumab-induced hypophysitis (IH) is a recently recognized endocrine IRAE.

METHODS

This review summarizes published data and experience from our center on the incidence, presentation and management, and proposed mechanisms for immunotherapy-related hypophysitis, with a focus on patients treated with ipilimumab (Ipi).

CONCLUSION

Hypophysitis occurs in a significant minority of patients treated with Ipi, in contrast to the relative rarity of idiopathic autoimmune hypophysitis or hypophysitis after treatment with other immunotherapies. Recently published cohorts have described the clinical presentation and management of IH and longitudinal outcomes in these patients. Additional studies with Ipi and other emerging agents have helped identify potential risk factors for the development of immunotherapy-related hypophysitis and possible underlying mechanisms for IH. Clarification of the mechanism(s) for IH may enhance our understanding of idiopathic autoimmune hypophysitis and could have potential therapeutic applications.

Endocrine side-effects of anti-cancer drugs: mAbs and pituitary dysfunction: clinical evidence and pathogenic hypotheses

mAbs are established targeted therapies for several diseases, including hematological and solid malignancies. These agents have shown a favorable toxicity profile, but, despite their high selectivity, new typical side-effects have emerged. In cancer patients, pituitary dysfunction may be mainly due to brain metastases or primary tumors and to related surgery and radiotherapy. Anticancer agents may induce hypopituitarism in patients cured for childhood cancers. These agents infrequently affect pituitary function in adult cancer patients. Notably, hypophysitis, a previously very rare disease, has emerged as a distinctive side-effect of ipilimumab and tremelimumab, two mAbs inhibiting the cytotoxic T-lymphocyte antigen-4 receptor, being occasionally seen with nivolumab, another immune checkpoint inhibitor. Enhanced antitumor immunity is the suggested mechanism of action of these drugs and autoimmunity the presumptive mechanism of their toxicity. Recently, ipilimumab has been licensed for the treatment of patients affected by metastatic melanoma. With the expanding use of these drugs, hypophysitis will be progressively encountered by oncologists and endocrinologists in clinical practice. The optimal management of this potentially life-threatening adverse event needs a rapid and timely diagnostic and therapeutic intervention. Hypopituitarism caused by these agents is rarely reversible, requiring prolonged or lifelong substitutive hormonal treatment. Further studies are needed to clarify several clinical and pathogenic aspects of this new form of secondary pituitary dysfunction.

Endocrine side effects induced by immune checkpoint inhibitors

CONTEXT

In recent years, progress has been made in cancer immunotherapy by the development of drugs acting as modulators of immune checkpoint proteins, such as the cytotoxic T-lymphocyte antigen-4 (CTLA4) and programmed death-1 (PD-1), two co-inhibitory receptors that are expressed on T cells upon activation. These molecules play crucial roles in maintaining immune homeostasis by down-regulating T-cell signaling, thereby preventing unbridled T-cell proliferation while maintaining tolerance to self-antigens, such as tumor-associated antigens. CTLA4 blockade through systemic administration of the CTLA4-blocking antibody ipilimumab was shown to confer significant survival benefit and prolonged stable disease in patients affected by advanced cutaneous melanoma. Other immune checkpoint inhibitors are under clinical evaluation. However, immune checkpoint blockade can lead to the breaking of immune self-tolerance, thereby inducing a novel syndrome of autoimmune/autoinflammatory side effects, designated as "immune-related adverse events," mainly including rash, colitis, hepatitis, and endocrinopathies.

DATA ACQUISITION

We searched the medical literature using the words "hypophysitis," "hypopituitarism," "thyroid," "adrenal insufficiency," and "endocrine adverse events" in association with "immune checkpoint inhibitors," "ipilimumab," "tremelimumab," "PD-1," and "PD-1-L."

EVIDENCE SYNTHESIS

The spectrum of endocrine disease experienced by patients treated with ipilimumab includes most commonly hypophysitis, more rarely thyroid disease or abnormalities in thyroid function tests, and occasionally primary adrenal insufficiency. Hypophysitis has emerged as a distinctive side effect of CTLA4-blocking antibodies, establishing a new form of autoimmune pituitary disease. This condition, if not promptly recognized, may be life-threatening (due to secondary hypoadrenalism). Hypopituitarism caused by these agents is rarely reversible, and prolonged or lifelong substitutive hormonal treatment is often required. The precise mechanism of injury to the endocrine system triggered by these drugs is yet to be fully elucidated.

CONCLUSIONS

Although reports of endocrine side effects caused by cancer immune therapy are abundant, their exact prevalence and mechanism are unclear. Well-designed correlative studies oriented to finding and validating predictive factors of autoimmune toxicity are urgently needed.

Hypophysitis induced by monoclonal antibodies to cytotoxic T lymphocyte antigen 4: challenges from a new cause of a rare disease

Specific human monoclonal antibodies antagonize cytotoxic T-lymphocyte antigen 4 (anti-CTLA-4 mAbs), a negative regulator of the immune system, inducing unrestrained T-cell activation. In patients with advanced or metastatic melanoma, one of these agents, ipilimumab, produced considerable disease control rates and, for the first time, a clear improvement in overall survival outcomes. However, accumulating clinical experience with anti-CTLA-4 mAbs identified a novel syndrome of autoimmune and autoinflammatory side effects, designated as "immune-related adverse events," including mainly rash, colitis, and hepatitis. Autoimmune hypophysitis has emerged as a distinctive side effect induced by anti-CTLA-4 mAbs. This condition may be life threatening because of adrenal insufficiency if not promptly recognized, but it may easily be diagnosed and treated if clinically suspected. Hypopituitarism caused by these agents is rarely reversible and prolonged or life-long substitutive hormonal treatment is often required. The precise mechanism of injury to the pituitary triggered by anti-CTLA-4 mAbs is yet to be fully elucidated.

Endocrine complications of human immunodeficiency virus infection: hypogonadism, bone disease and tenofovir-related toxicity

Treatment with highly active antiretroviral therapy (HAART) has revolutionized care of patients with HIV infection. The cost of increased survival has been antiretroviral toxicity and increasing age-related co-morbidities that include significant metabolic issues. Hypogonadism was first described in the setting of advanced AIDS and can be primary or secondary. Data regarding treatment largely concern patients with wasting. Varied syndromes involving bone have been described in patients with HIV including osteonecrosis, low bone mineral density (BMD) and osteoporosis, and rarely osteomalacia. Low BMD leading to osteoporosis is the most common bone pathology and may be as a result of HIV infection, drug toxicity or co-morbidities. However, increasingly fragility fractures are reported in HIV-infected patients, suggesting bone demineralization in this population is of clinical relevance. Further research is required to understand its pathogenesis and determine effective management; however, initiation of antiretroviral therapy seems to accelerate (in the short-term) bone demineralization. One particular antiretroviral agent, tenofovir is widely used and is potentially implicated as having a greater role in long-term bone and renal dysfunction. As this population ages, screening for low BMD will become increasingly more important.

Histopathologic findings of autoimmunity in thyroid, pituitary, and adrenal diseases in chronic hepatitis C postmortem cases

OBJECTIVE

To assess the histologic prevalence of immune-mediated thyroid, pituitary, and adrenal diseases in postmortem cases with hepatitis C.

METHODS

We reviewed 108 consecutive cases of chronic hepatitis C in patients in whom a complete postmortem examination was performed. All microscopic and histologic slides of the thyroid, pituitary, and adrenal reports were reviewed and assessed for evidence of autoimmune diseases. These were compared with a control group of 100 postmortem cases without hepatitis C.

RESULTS

In chronic hepatitis C infection, there is a heightened immune response resulting in many autoimmune diseases. The commonest endocrinopathy in association with this chronic infection is thyroid disease, a finding confirmed in our current study. Among the 108 postmortem cases of hepatitis C, there were 14 cases (13%) with evidence of thyroiditis. No cases of pituitary or adrenal disease were found. The mean age of the patients was 52 years (range, 29 to 68). This frequency compared with 7 cases of thyroid disease (7%) in the control group (no significant difference between the 2 groups).

CONCLUSION

On the basis of our postmortem data, thyroid disease was the only major endocrinopathy associated with hepatitis C infection, with a prevalence of 13%. This was comparable with other serologic and nonhistologic antemortem findings. There was no evidence of pituitary or adrenal involvement.

Advance in the relationship between thyroid function and liver diseases

Numerous researches have showed that thyroid diseases affect liver function and progression of liver diseases; conversely, liver diseases, especially severe liver disease, can also affect thyroid function. Thyroid function may have changes in patients with chronic viral hepatitis treated with interferon. So physicians should pay more attention to the relationship between thyroid and liver diseases during the course of diagnosis and treatment.

Autoimmune hypophysitis of SJL mice: clinical insights from a new animal model

Autoimmune hypophysitis (AH) is a rare but increasingly recognized disease of the pituitary gland. Its autoantigens are unknown, and the management is difficult because it is often misdiagnosed as a nonsecreting adenoma. By immunizing female SJL/J mice with mouse pituitary extracts, we established a new mouse model of experimental AH. Immunized mice developed severe lymphocytic infiltration in the anterior pituitary that closely mimicked the human pathology. In the early phase of experimental AH, the pituitary enlarged, consistent with the compression symptoms reported by hypophysitis patients at presentation. In the florid phase, adrenal insufficiency and pituitary antibodies developed, in strong correlation with the pituitary pathology. In the late phase, hypothyroidism ensued, and the pituitary gland became atrophic. Using immune sera as probes in a two-dimensional immunoblotting screen followed by mass spectrometry, we identified several proteins that could function as pituitary autoantigens. These findings provide new insights into the pathogenesis of AH, and establish a platform for developing novel diagnostic biomarkers and therapeutics.

Granulomatous Adenohypophysitis after Interferon and Ribavirin Therapy

OBJECTIVE

To describe a case of granulomatous hypophysitis occurring after treatment with interferon alfa-2b and ribavirin for hepatitis C.

METHODS

Clinical, radiologic, laboratory, and pathologic assessments of a woman with granulomatous hypophysitis and interferon-induced thyroiditis are presented.

RESULTS

A 42-year-old woman with hepatitis C was treated with interferon alfa-2b and ribavirin for 5 months. She was referred after symptoms of thyrotoxicosis developed, in conjunction with laboratory and radiographic evidence of thyroiditis. During the initial evaluation, she was weak and hypotensive; biochemical evaluation showed undetectable plasma cortisol and corticotropin concentrations. Magnetic resonance imaging revealed diffuse enlargement of the pituitary gland, which encroached on but did not compress the optic chiasm. Treatment with supraphysiologic doses of prednisone resulted in clinical and radiographic improvement. Once physiologic doses of glucocorticoids were instituted, however, follow-up magnetic resonance imaging showed substantial progression of the diffuse pituitary enlargement and mild compression of the optic chiasm. Surgical debulking of the mass and histologic evaluation showed chronic, noncaseating granulomatous hypophysitis. An extensive evaluation for secondary causes of granulomatous inflammation of the pituitary revealed only an elevated angiotensin-converting enzyme level; no organisms were identified. After 2 courses of high-dose glucocorticoids, she had radiographic evidence of decreased size of the pituitary lesion but continued to have multiple anterior pituitary hormone deficiencies.

CONCLUSION

Granulomatous hypophysitis and sarcoidosis of the pituitary are rare disorders. Hypophysitis should be considered in patients receiving interferon and ribavirin therapy who have symptoms consistent with pituitary dysfunction.

Side effects of interferon-alpha therapy

AIM

Interferon-alpha (IFN-alpha) has been extensively explored for its efficacy in various disease conditions and is currently used as a standard treatment in several of these. Its use is accompanied by a wide variety of possible side effects. These side-effects may hamper reaching and maintaining the dose needed for maximal therapeutic effect while their occurrence can outweigh clinical benefit of IFN-alpha treatment. This review addresses the toxicity profile of IFN-alpha, the presumed pathophysiology of the different side effects and the strategies to handle these.

METHODS

Computerized searches were used and cross-references of articles and books were checked.

RESULTS

Adverse effects due to IFN-alpha have been described in almost every organ system. Many side-effects are clearly dose-dependent. Taken together, occurrence of flu-like symptoms, hematological toxicity, elevated transaminases, nausea, fatigue, and psychiatric sequelae are the most frequently encountered. Although insight in the mechanisms accounting for IFN-alpha-related toxicities has improved in recent years, much remains to be elucidated. Guidelines on the management of these untoward sequelae are mostly based on clinical experience, while many side-effects can only be adequately handled by dose adjustment or cessation of treatment.

CONCLUSION

Further research on the mechanisms underlying both therapeutic effects and adverse events is warranted. Hopefully, this will lead to better identification of those patients who are likely to benefit from treatment without experiencing severe toxicities.

Diagnosis and treatment of androgen deficiency in human immunodeficiency virus-infected men and women

Androgen deficiency is a common endocrine abnormality among men and women with human immunodeficiency virus (HIV) infection. Low testosterone concentrations are associated with lower CD4 cell count, advanced stage of illness, medication use, and weight loss. Signs and symptoms may be nonspecific. The most useful laboratory indicator is the serum bioavailable (free) testosterone concentration. A number of different testosterone preparations for treatment of androgen deficiency in HIV-infected men now exist. Administration of im testosterone significantly increases weight and lean body mass, energy, quality of life, and depression scores in HIV-infected men with low testosterone levels. Newer transdermal and gel preparations provide more-consistent steady-state dosing but are not as well tested, and sufficient testosterone concentrations may not be achieved with their use. Androgen deficiency is also common among HIV-infected women. Preliminary studies suggest that use of physiological testosterone administration, to achieve testosterone levels within the normal range, is of benefit in HIV-infected women, but further studies are necessary to define the therapeutic role of androgen therapy in this population.

Endocrine and neurological adverse effects of the therapeutic interferons

There is experimental evidence that the nervous central and the neuroendocrine systems can influence the immune system, which can in turn influence the brain activity. Endogenous cytokines are known to play a critical role in the pathophysiology of many diseases. The recently acquired experience on the adverse effects of therapeutic cytokines, particularly neurological and endocrine adverse effects, are further illustrative of these interferences. Interferons-alpha have been used in thousands of patients, so that the information accumulated with this group of closely related products is essential to delineate the potential and severity for non-immunological, but largely immune-mediated adverse effects to develop in patients treated with immuno-activating agents.

Long-term interferon-alpha therapy does not affect sex hormones in males with chronic hepatitis C

The effects of interferon-alpha (IFN-alpha), given at a dosage of 6 MU thrice weekly for 12 months, on gonadal function were investigated in 18 males affected by chronic hepatitis C. Periodically, all patients were clinically monitored and questioned about sexual function. Gonadotropin and serum androgen concentrations (follicle-stimulating hormone, luteinizing hormone, total testosterone, free testosterone, androstenedione, dehydroepiandrosterone, dehydroepiandrosterone sulfate, and sex hormone binding globulin) were tested every 3 months. Ten of 18 patients (55%) responded to IFN-alpha therapy. Serum total testosterone and sex hormone binding globulin values decreased slightly at the third month of treatment, then returned to baseline values. Serum free testosterone and other sex hormones remained essentially unchanged during IFN-alpha therapy. Four patients (22.2%) complained of sexual dysfunction (impaired libido, erectile failure, and impaired ejaculation), which was unrelated to any significant hormonal change and resolved after IFN therapy was stopped. Serum sex hormones values did not differ between responders and nonresponders to IFN-alpha. This study indicates that 12 months treatment with 6 MU of IFN-alpha thrice weekly does not significantly affect gonadal function in men with chronic hepatitis C. The sexual dysfunction observed could be ascribed to such other side effects of IFN as asthenia, fatigue, or anxiety, or it could have a psychologic basis.

Case report: interferon induced coma in Sheehan's syndrome

A 54-year-old woman who was being treated with 10 million units (mu) of natural interferon (IFN)-alpha per day for chronic active hepatitis C at a local clinic, developed coma on the fourth day of treatment. On admission to Yamagata University Hospital, she was still in a state of semicoma with severe hyponatraemia (122 mEq/L) and hypochloraemia (89 mEq/L). After the administration of electrolytes, her condition improved remarkably. Endocrinological loading tests showed a hypofunction of the anterior pituitary gland. In consideration of these results, and her past experiences of haemorrhage during childbirth and subsequent amenorrhoea, we diagnosed her illness as a coma as a result of Sheehan's syndrome which had become overt during IFN therapy. She recovered completely after treatment with hydrocortisone and l-thyroxine.

Endocrine implications of human immunodeficiency virus infection

Endocrine abnormalities occur frequently in HIV-infected patients. Although the majority of endocrine disorders reflect chronic infection, stress, and malnutrition, some disorders are characteristic of HIV infection or AIDS and deserve particular clinical attention. Identification of HIV patients at risk of frank endocrine disorders, rapid and correct diagnosis, and appropriate management are essential steps to minimize morbidity and mortality. Finally, increasing evidence from in vitro studies suggests that various hormones may influence HIV replication as well as the course of HIV disease and associated disorders. Future studies on the molecular mechanisms of hormones on HIV action and clinical studies on the effects of hormones as adjunctives to established forms of therapy may stimulate development of novel therapeutic strategies that will benefit HIV-infected patients.