A Pediatric Case of Relapsing Eosinophilic Granulomatosis with Polyangiitis Successfully Treated with Mepolizumab

Anti-IL-5 Pathway Agents in Eosinophilic-Associated Disorders Across the Lifespan

Monoclonal antibodies targeting interleukin (IL)-5 pathways have revolutionized the treatment expectations for eosinophilic-associated conditions, particularly in patients with respiratory involvement. Mepolizumab (IL-5 antagonist monoclonal antibody), benralizumab (IL-5 receptor blocker monoclonal antibody), and reslizumab (IL-5 antagonist monoclonal antibody) have collectively contributed to the overall improvement of the disease burden in various conditions. Eosinophilic asthma currently boasts the most robust evidence across all age groups: all three biologics are approved for adults (aged ≥18 years); mepolizumab is approved by the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA) also in children (aged ≥ 6 years), while bernalizumab was recently approved by the FDA for patients aged ≥6 years in the USA. In chronic rhinosinusitis with nasal polyps, subcutaneous mepolizumab is the only anti-IL-5 therapy approved so far and can be used in adult patients (aged ≥18 years). For eosinophilic esophagitis, conflicting evidence surrounds both mepolizumab, reslizumab, and benralizumab, leading to non-approval of these agents by the FDA/EMA. Recently, mepolizumab was approved for eosinophilic granulomatosis with polyangiitis patients aged ≥6 years or older and for hypereosinophilic syndrome adult patients. A phase III trial proving noninferiority of benralizumab versus mepolizumab in eosinophilic granulomatosis with polyangiitis has been recently published, while evidence on reslizumab is scant. Overall, current evidence on anti-IL-5 biologics for eosinophilic-associated disorders is mostly focused on adults, whereas data for individuals aged under 18 years and over 65 years are scarce, resulting in a lack of evidence, particularly regarding efficacy, for the use of anti-IL-5 agents in these specific patient populations. This review addresses high-quality evidence from randomized controlled trials and real-world post-marketing studies regarding the use of anti-IL-5 therapies for eosinophilic-associated disorders across all age groups, spanning childhood, adulthood, and older age.

Therapeutic Advances in Eosinophilic Granulomatosis with Polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA) is an eosinophilic vasculitis that affects a variety of organ systems. Historically, glucocorticoids and a variety of other immunosuppressants were used to abrogate the inflammation and tissue injury associated with EGPA. The management of EGPA has evolved greatly during the last decade with the development of novel targeted therapeutics that have resulted in significantly improved outcomes for these patients, with many more novel targeted therapies emerging.

Long-term mepolizumab treatment reduces relapse rates in super-responders with eosinophilic granulomatosis with polyangiitis

BACKGROUND

The mainstay of treatment for eosinophilic granulomatosis with polyangiitis (EGPA) is systemic corticosteroid therapy; some patients also receive intravenous immunoglobulins, other immunosuppressive agents, and biologics. Mepolizumab, an anti-interleukin-5 monoclonal antibody, induces remission and decreases the daily corticosteroid dose; however, the clinical efficacy of mepolizumab in EGPA and the prognosis with long-term treatment with this drug are unknown.

METHODS

Seventy-one EGPA patients were treated at Hiratsuka City Hospital, Japan, between April 2018 and March 2022. We administered mepolizumab for a mean of 2.8 ± 1.7 years to 43 patients in whom remission could not be induced by conventional treatment. After excluding 18 patients who had received mepolizumab for less than 3 years, we classified 15 patients into a "super-responder group" (the daily dose of corticosteroids or other immunosuppressant could be decreased, or the interval between IVIG treatments could be prolonged) and 10 patients into a "responder group" (neither of these changes was achievable). Eosinophil numbers, serum IgG levels, daily doses of corticosteroids and other immunosuppressants, Birmingham Vasculitis Activity Score (BVAS), and relapse frequency before and after mepolizumab initiation were determined.

RESULTS

Blood eosinophil count at diagnosis and the lowest serum IgG level before mepolizumab treatment were significantly higher in super-responders than in responders (p < 0.05). In super-responders, the prednisolone dose at last visit on mepolizumab treatment was lower than that before treatment (p < 0.01) and lower than that at last visit in the responders (p < 0.01). In both groups, peripheral blood eosinophil numbers and BVAS were lower after starting mepolizumab than before (p < 0.01). BVAS before mepolizumab (p < 0.05) and at last visit (p < 0.01) were lower in super-responders than in responders. Relapse rates every year after the start of mepolizumab were lower in super-responders than in responder groups (p < 0.01). In super-responders, relapse rates were lower during the 3 years following mepolizumab initiation (p < 0.01) and at last visit (p < 0.01) were significantly lower than after 1 year of treatment.

CONCLUSION

Mepolizumab treatment of super-responders sustainably reduced the relapse rate.

The role of anti-eosinophilic therapies in eosinophilic granulomatosis with polyangiitis: a systematic review

Eosinophilic granulomatosis with polyangiitis (EGPA) is an antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis, mostly affecting small-sized arteries and usually occurring in patients with an allergic background. Eosinophils seem to play a significant role in the pathogenesis of the disease and, therefore, biologics targeting interleukin 5 (IL5), a cytokine tightly linked to eosinophils, have emerged as a promising therapeutic tool. A systematic review of Medline was conducted from 2007 to 2022 to search for data regarding the use of anti-IL5 therapies in patients with EGPA. Ongoing or unpublished trials were also searched in ClinicalTrials.gov and the World Health Organization trials portal. The efficacy and safety of mepolizumab, an anti-IL5 monoclonal antibody (mAb), was confirmed by a randomized controlled trial (RCT), although a significant proportion of patients did not respond to this treatment. Other studies showed that both doses of 100 mg and 300 mg of mepolizumab are almost equally effective in EGPA. Benralizumab, an anti-IL5 receptor mAb has preliminary promising results and an RCT is planned to be conducted. Apart from their clinical efficacy in EGPA, anti-IL5 therapies may have steroid-sparing properties. Anti-IL5 therapies seem to be effective and safe in patients with refractory/relapsing EGPA and can be used as a steroid-sparing treatment. Nevertheless, more research is needed to clarify the pathophysiology of the disease; this may potentially lead to the identification of biomarkers to pinpoint patients most likely to respond to anti-IL5-blockade.

Mepolizumab: Therapeutic strategy for a pediatric patient with eosinophilic granulomatosis with polyangiitis

Eosinophilic granulomatosis with polyangiitis (EGPA; formerly known as Churg-Strauss syndrome) is classified as an antineutrophil cytoplasmic antibody (ANCA)-associated small vessel vasculitis. It is a multisystem disorder and can affect every organ system. EGPA is a rare disease, with an estimated prevalence of 1/70,000-100,000 in Europe. As its onset usually occurs in adulthood, data from pediatric patients are limited. We present here a very rare practical EGPA clinical case involving a pediatric patient. Presently, data on mepolizumab usage in pediatric patients are limited, with only a few case reports published.

Safety and effectiveness of mepolizumab therapy in remission induction therapy for eosinophilic granulomatosis with polyangiitis: a retrospective study

OBJECTIVES

To investigate the safety and effectiveness of mepolizumab (MPZ), an anti-interleukin-5 antibody, as remission induction therapy for severe eosinophilic granulomatosis with polyangiitis (EGPA).

METHODS

The clinical courses of patients with severe EGPA over 6 months were retrospectively investigated and compared between patients treated with high-dose corticosteroid (CS) plus MPZ therapy (MPZ group, n = 7) and those treated with high-dose CS plus intravenous cyclophosphamide (IVCY) pulse therapy (IVCY group, n = 13). The primary endpoints were the MPZ retention rate and the IVCY completion rate. The secondary endpoints were adverse events and changes in the Birmingham Vasculitis Activity Score (BVAS), Vascular Damage Index (VDI), eosinophil counts, and concomitant CS doses, and the extent and rates of these changes were compared between the MPZ and IVCY groups.

RESULTS

Regarding the primary endpoints, the MPZ retention rate was 100%, and the IVCY completion rate was 61.5%. Regarding the secondary endpoints, adverse events were detected in 2/7 patients (28.6%) in the MPZ group and 7/13 patients (53.8%) in the IVCY group. BVAS and eosinophil counts significantly decreased in both groups at and after month 1, but there was no significant difference in the magnitude of changes between the two groups. VDI scores did not significantly increase in either group, and the degree of changes did not significantly differ between the two groups. Although concomitant CS doses significantly decreased at and after month 1 in both groups, the rates of decrease in CS doses at and after month 3 were significantly higher in the MPZ group.

CONCLUSIONS

This study suggested that the use of MPZ as remission induction therapy for severe EGPA might be safe and effective for controlling disease activity and reducing CS doses.

A Patient with Eosinophilic Granulomatosis with Polyangiitis Successfully Weaned from Corticosteroids Through Remission Induction Therapy with Mepolizumab

The patient was a 74-year-old man who was admitted to our hospital for fever, purpura, abdominal pain, and bilateral numbness. Although the patient tested negative for anti-neutrophil cytoplasmic antibody (ANCA), he presented with an elevated peripheral eosinophil count, increased inflammatory responses, duodenitis, cholecystitis, lung lesions, renal disorder, and peripheral neuropathy. The skin biopsy findings revealed vasculitis. Thus, the patient was diagnosed with eosinophilic granulomatosis with polyangiitis (EGPA). Given the advanced age of the patient, in addition to the poor general condition and hepatic and renal dysfunction, administration of immunosuppressants was considered to pose a high risk. After obtaining informed consent, remission induction therapy was initiated with mepolizumab (300 mg/M) in combination with high-dose corticosteroid therapy (equivalent to 70 mg/day of prednisolone). After treatment initiation, eosinophil counts and inflammatory responses decreased. Moreover, the abdominal pain and purpura resolved, and renal/hepatic dysfunction and peripheral neuropathy also improved. While the corticosteroid dose was subsequently reduced, no relapse was observed. Approximately 2 years later, the corticosteroid was discontinued. After the discontinuation of the corticosteroid, the patient continued treatment with mepolizumab alone and has remained in remission for approximately 6 months. Therefore, mepolizumab may be useful as a remission induction therapy in ANCA-negative EGPA resistant to steroids.

Clinical Features of Patients with Active Eosinophilic Granulomatosis with Polyangiitis Successfully Treated with Mepolizumab

BACKGROUND

In some patients with eosinophilic granulomatosis with polyangiitis (EGPA), remission cannot be induced, despite treatment with corticosteroids and immunosuppressants. We evaluated the clinical features of patients with EGPA in whom mepolizumab was effective.

METHODS

There were 59 EGPA patients treated at Hiratsuka City Hospital, Japan, between April 2018 and September 2020, and 30 of them received mepolizumab. Twenty (66.7%) experienced a "marked effect" (the daily dose of corticosteroid or immunosuppressant could be decreased, or the interval between intravenous immunoglobulin (IVIG) treatments could be prolonged) and 10 (33.3%) experienced a "weak effect" (these measures were not achieved). Eosinophil numbers, serum IgG levels, daily doses of corticosteroids and immunosuppressants, and the interval between IVIG treatments at diagnosis and before and after mepolizumab initiation were determined.

RESULTS

Eosinophil numbers at diagnosis were significantly higher in the marked-effect group than in the weak-effect group (p < 0.05) but not before mepolizumab initiation or at the last visit. Birmingham Vasculitis Activity Scores (BVASs) before mepolizumab initiation (p < 0.05) and at last visit (p < 0.01), and frequency of relapse before treatment initiation (p < 0.05) were significantly higher, and the serum IgG level before mepolizumab treatment was significantly lower in the weak-effect group than in the marked-effect group. The weak-effect group received higher doses of corticosteroids, even if the corticosteroid dose could be reduced for a while after mepolizumab initiation.

CONCLUSION

High peripheral blood eosinophil numbers at EGPA diagnosis were suggestive of a positive clinical response to mepolizumab.

Effectiveness and safety of mepolizumab in combination with corticosteroids in patients with eosinophilic granulomatosis with polyangiitis

Background

Mepolizumab (MPZ), an anti-interleukin-5 antibody, is effective for the treatment of eosinophilic granulomatosis with polyangiitis (EGPA). However, its effectiveness has not been adequately evaluated in real-world clinical practice. In this study, we assessed the effectiveness and safety of MPZ (300 mg) for relapsing/refractory EGPA resistant to corticosteroids (CS) for 1 year in real-world settings.

Methods

We administered MPZ (300 mg) to 16 patients with relapsing/refractory EGPA resistant to CS (Post-MPZ). We also retrospectively collected data from the same patients for the 12 months before the administration of MPZ (Pre-MPZ). The primary endpoint was the 12-month remission rate after MPZ administration and the secondary endpoints were the Birmingham vasculitis activity score (BVAS), vasculitis damage index (VDI), eosinophil counts, changes in concomitant CS doses/concomitant immunosuppressant use, MPZ retention rate, and incidence of adverse events. The clinical course was compared between Pre-MPZ and Post-MPZ.

Results

The 12-month remission rate after the initiation of MPZ was 75%. No change was observed in BVAS, eosinophil count, or concomitant CS dose over time in the Pre-MPZ group, whereas all these parameters were significantly decreased over time in the Post-MPZ group. The number of patients using concomitant immunosuppressant also decreased over time in the Post-MPZ group. VDI did not increase in either group. The MPZ retention rate was 100% and only three patients (18.8%) had infections. Changes in BVAS, eosinophil count, and cumulative concomitant CS dose were significantly lower in the Post-MPZ group than in the Pre-MPZ group. There was no significant difference in the changes in VDI between the groups.

Conclusion

This study demonstrated that MPZ is effective and safe for EGPA. Furthermore, MPZ decreases disease activity, increases remission rate, and has a CS-sparing effect.