IgG4関連疾患市場 - 市場の洞察、疫学、市場予測：2034年

主なハイライト

• IgG4-RDは、膵臓、胆管、唾液腺、涙腺、眼窩、腎臓、肺、後腹膜など、事実上あらゆる臓器に発症する可能性があります。
• IgG4-RDの真の有病率は不明です。IgG4-RDの発見が比較的最近であること、広く認識されていないこと、およびしばしば緩徐に発現することから、認知度および報告度が低いと考えられます。男性優位であり、大規模コホートにおける診断時の平均年齢は30歳代から50歳代です。しかし、古典的な症例は小児患者にも観察されています。
• 2024年に主要7ヶ国で診断されたIgG4-RDの有病者数は約14万8,970人でした。このうち、米国がIgG4-RDと診断された有病者数が最も多いです。
• 米国、EU4ヶ国、英国のシナリオとは対照的に、日本では診断有病率を示す複数の研究が実施されています。したがって、2015年から2018年にかけてのIgG4関連疾患の診断の激増に関する証拠とともに、日本のナショナルデータベースからの10年間の累積診断有病率推定に基づくと、2024年の日本における診断有病数は～3万8,690例となります。
• IgG4と診断された患者のほぼ20～30％は全身療法別治療を受けず、手術を選択するか、経過を観察しています。
• IgG4-RDは病態生理が不明確であるため、特異的な治療薬はなく、承認された治療法もありません。主な治療はプレドニゾンなどの副腎皮質ステロイド薬別炎症と症状の管理です。再発したり効果がない場合は、ステロイド依存性を軽減するためにアザチオプリンやメトトレキサートなどの免疫抑制剤が使用されます。抗CD20モノクローナル抗体であるリツキシマブも炎症を抑制し、病気の進行を遅らせる効果があります。グルココルチコイドは依然として第一選択薬です。
• 現在の制約のあるパイプラインには、3つの新しい治療薬：アップリズナ（Amgen）、オベキセリマブ（Zenas BioPharma、Bristol Myers Squibb）、リルザブルチニブ（Sanofi）です。これらの新興治療薬のうち、アップリズナとオベキセリマブは互いに強く競合すると予想されます。
• 2025年4月に承認されると予想されるアップジルナは、IgG4-RD市場を一変させ、この十分な治療を受けていない疾患に対して初めて承認された治療薬となります。それは、治療の展望を再定義し、より高い診断率を促進し、価格設定と医師の採用を通じて商業力学を形成すると思われます。しかし、市場教育、実臨床での検証、将来の競合が、長期的な影響に影響を及ぼすとみられています。
• リルザブルチニブは第Ⅱ相の治療薬であり、B細胞シグナル伝達経路を標的とする有望な経口治療薬です。承認されれば、より簡便な自己投与の選択肢を提供することで、点滴／SC生物学的製剤市場を混乱させる可能性があります。
• 2024年、主要7ヶ国におけるIgG4-RDの総市場規模は約1億7,000万米ドルでした。この市場規模は、パイプラインにある潜在的な新興治療薬が承認された後、大幅な成長が見込まれます。

当レポートでは、IgG4関連疾患市場について調査し、米国、EU4ヶ国（ドイツ、フランス、イタリア、スペイン）、英国、日本の市場動向とともに、過去の疫学と予測について詳細な理解を提供します。現在の治療法、新薬、個々の治療法の市場シェア、2020年から2034年までの現在および予測主要7ヶ国市場規模を提供します。また、現在の治療法/アルゴリズム、アンメットメディカルニーズも網羅し、最良の機会を発掘し、市場の可能性を評価します。

IgG4-RDは、血漿中IgG4濃度の上昇の有無にかかわらず、罹患組織におけるIgG4陽性形質細胞の密集浸潤を特徴とする全身性の線維性炎症性疾患です。慢性線維性炎症性疾患であり、様々な臓器に影響を及ぼします。血清IgG4濃度の上昇およびIgG4発現形質細胞の豊富な浸潤は、この自己免疫疾患の主要な診断的特徴です。IgG4-RDの一般的な臓器病変は唾液腺、膵臓および胆管であるが、肝病変はあまり確立されていないです。

IgG4-RDは、Mikulicz病、自己免疫性膵炎、甲状腺機能低下症、Riedel甲状腺炎、間質性肺炎、間質性腎炎、前立腺炎、リンパ節腫脹、後腹膜線維症、炎症性大動脈瘤、および炎症性偽腫瘍を含む様々な疾患を有する患者の一定割合に認められることがあります。

IgG4-RDは同時に複数の臓器に罹患する可能性があるため、診断が難しいです。診断には、臨床検査、内視鏡検査、X線検査、血清学的検査を行い、臓器病変や末端臓器障害（ホルモンバランスの乱れなど）を調べる必要があります。組織診断には、皮膚を含む罹患臓器組織の生検が必要です。血液検査で血清IgG4濃度の上昇と末梢好酸球増多が認められることがあります。

血清IgG4濃度は最も重要なバイオマーカーであり、患者の最大90％で高値が認められるが、これにはばらつきがあります。IgG4濃度の低下は治療効果を示すことが多いが、長期間生存する形質細胞のため、寛解期であっても正常値に戻らないことがあります。IgG4の上昇は他の疾患でも起こりうるため、その価値はより広い臨床的背景の中で考慮されなければならないです。IgG1、IgE、好酸球増多、補体レベル（C3およびC4）などのその他のバイオマーカーも疾患活動性を反映することがあり、IgG4関連腎疾患では低補体血症が顕著にみられます。

IgG4-RDの場合、治療は必ずしも必須ではなく、無症状の場合は注意深く待つことが適切な場合もあります。一方、IgG4-RDは主要な臓器の機能不全や障害を引き起こす可能性があるため、重要な臓器が関与している場合、または患者が症状を示した場合には、迅速な治療が必要となります。

IgG4-RDの治療に関する国際的なコンセンサス・ステートメントによると、グルココルチコイドは膵臓および膵臓外疾患のほとんどの症例で劇的な臨床効果をもたらすため、第一選択薬です。そのため、様々なグルココルチコイドを温存する薬剤が、寛解維持薬として様々な解剖学的領域で使用されており（例えば、アザチオプリン、ミコフェノール酸モフェチル、メトトレキサート、シクロホスファミド、ボルテゾミブ）、その結果は様々です。

アザチオプリン、ミコフェノール酸モフェチル、メトトレキサートなどのステロイド温存薬の使用は、グルココルチコイドの副作用を軽減し、寛解を持続させるために用いられるが、その有効性の証明は不十分です。リツキシマブ療法は、より最近の有望な代替療法です。CD20陽性の形質芽細胞前駆体を枯渇させる。形質芽細胞が減少すると、IgG4合成は減少します。

グルココルチコイド治療に対する迅速な反応が特徴的な所見として指摘されたAIPの初期の記述以来、グルココルチコイドはIgG4-RDの第一選択治療とみなされてきました。発表されたIgG4-RDの管理に関するコンセンサス・ステートメントによれば、IgG4-RDの専門家の大多数は、活動性の未治療疾患に対する第一選択薬はグルココルチコイドであると考え続けています。プレドニゾンは寛解導入の第一段階として頻繁に使用されます。ほとんどの患者は数日から数週間以内にグルココルチコイド治療に反応し、その大部分は数ヵ月以内に寛解に達します。

• 2024年、米国におけるIgG4-RD有病者総数は約5万6,800例で、予測期間中（2025年～2034年）に増加すると予測されます。
• 2024年、米国における性別ごとの診断有病者数は、男性が約3万9,100人、女性が約17,700人でした。
• EU4ヶ国と英国における2024年のIgG4-RD診断有病者総数は約5万3,550人でした。男性は約3万8,850例、女性は1万4,750例でした。
• 年齢層の分類は6つの年齢グループ、すなわち0～17歳、18～29歳、30～44歳、45～64歳、65～74歳、75歳以上を考慮しました。我々の分析別と、日本では75歳以上の年齢層で診断された有病者の割合が高いことが観察されました。2024年、日本におけるIgG4-RDの年齢別診断有病者数は、75歳以上で約1万2,800人でした。予測期間中（2025年～2034年）、症例は増加します。

オベクセリマブ（XmAb5871）：Zenas BioPharmaとBristol Myers Squibb

オベキセリマブ（XmAb5871）は、B細胞系に広く存在するCD19とFcRIIbの両方に結合するように設計された二機能性モノクローナル抗体で、多くの自己免疫疾患に関与する細胞の活性を枯渇させることなく阻害します。このユニークな作用機序と自己投与可能なSC注射レジメンは、慢性自己免疫疾患におけるB細胞系列の病原的役割に広範かつ効果的に対処する可能性があります。

現在、Zenas社は、IgG4-RD、多発性硬化症、全身性エリテマトーデス、温熱性自己免疫性溶血性貧血を含むいくつかの自己免疫疾患において、オベキセリマブの複数の第II相および第III相臨床試験を実施しています。2023年8月、Lancet Rheumatology誌は、IgG4-RD患者の治療に対するオベキセリマブを評価した第II相試験の結果を発表しました。これらの結果に基づき、IgG4-RD患者を対象とした第III相試験が進行中であり、オベキセリマブをSC注射剤として投与した場合の有効性と安全性をさらに検討しています。

アップリズナ（イネビリズマブ）：Amgen

UPLIZNAはヒト化モノクローナル抗体で、基礎疾患プロセスに寄与する主要な細胞（形質芽細胞や一部の形質細胞を含む自己抗体を産生するCD19+B細胞）を標的として持続的に枯渇させる。初回注入を2回行った後、患者は6カ月ごとにアップリズナを1回投与する必要があります。アップリズナは現在、視神経脊髄炎の治療薬として承認されています。現在、同剤は第III相試験を終了しており、FDAはPDUFA発効日を2025年4月3日としています。

アップリズナは、IgG4-RDの現在の治療選択肢における重大なギャップを解決すると同時に、患者に大きな利益を提供し、この複雑でしばしば衰弱する症状を管理するための、初めて承認された基幹治療薬になると期待されています。将来的には、オベキセリマブが承認され、二機能性標的薬として競合する可能性があります。

現在のIgG4-RDの新薬状況には3つの薬剤しかありません。その中で、CD-19を標的とするのはオベキセリマブ（二機能性）とアップリズナです。B細胞に存在するタンパク質であるCD19を標的とする治療は、IgG4-RDの発症に関与すると考えられているB細胞を減少させることにより、IgG4-RDの治療薬として有望です。具体的には、CD19を標的とする抗体であるアップリズナは、IgG4-RD患者の再燃を抑え、寛解を達成する有効性を実証しています。

IgG4-RDの病因は不明であり、現在も研究中であるため、特定の薬剤で治癒することはできません。IgG4-RD患者に対しては、現時点では承認された治療薬は市販されていないです。IgG4-RDの管理および治療に関する国際的なコンセンサス・ガイダンス・ステートメント"によって最近発表されたガイドラインには、IgG4レベルによって引き起こされる疾患を特定するための基準および患者の治療に関する推奨事項が詳述されています。

活動性あるいは未治療のIgG4-RD患者は通常、第一選択薬としてグルココルチコイドを投与されます。病態の重症度や緊急性にもよりますが、寛解導入にはプレドニゾン30～40mg/日、あるいは体重調整量として0.6mg/kgを毎日投与することが多いです。

場合によっては、IgG4-RDの治療に従来の「疾患修飾性抗リウマチ薬」（DMARDs）が使用されます。形質芽細胞は、あらゆるリウマチ性疾患において有効なバイオマーカーとなる最初の細胞であり、B細胞におけるテーラーメイド治療は、疾患活動性を追跡するために総形質芽細胞濃度を用います。

IgG4-RDを管理するために数多くの潜在的治療法が研究されていることから、予測期間中に治療領域が大きく再構成されることは間違いありません。しかし、価格設定と償還に伴う課題が、これらすべてのパイプライン治療薬の運命と、それらが全体的な収益に与える影響を決定することになります。

Zenas BioPharma、Amgen、Sanofiといった主な開発企業は、それぞれ異なる臨床開発段階でリード候補を評価しています。これらの企業は、IgG4-RDを治療するために自社製品を調査することを目指しています。

当レポートでは、主要7ヶ国におけるIgG4関連疾患市場について調査し、市場の概要とともに、疫学、患者動向、新たな治療法、2034年までの市場規模予測、および医療のアンメットニーズなどを提供しています。

目次

第1章 重要な洞察

第2章 報告書のイントロダクション

第3章 エグゼクティブサマリー

第4章 主要な出来事

第5章 疫学と市場予測の調査手法

第6章 IgG4-RD市場概要

• IgG4-RD治療薬市場シェア（％）分布、2024年
• IgG4-RD治療薬市場シェア（％）分布、2034年

第7章 疾患の背景と概要

• イントロダクション
• 臨床表現型
• IgG4-RDに関連する組織学
• IgG4-RDに関連する病態
• 疾患のサブタイプと臨床症状
• IgG4-RDに関連する兆候と症状
• IgG4-RDの診断評価
• IgG4-RDの治療と管理
• IgG4-RDのガイドライン、推奨事項、および管理

第8章 主要7ヶ国におけるIgG4-RDの疫学と患者人口

• 主な調査結果
• 仮定と根拠
• 主要7ヶ国におけるIgG4-RDの診断された有病症例の総数
• 米国
• EU4ヶ国と英国
• 日本

第9章 患者動向

第10章 新興薬剤

• キークロス競合
• オベセリマブ（XmAb5871）：Zenas BioPharmaとBristol Myers Squibb
• UPLIZNA（イネビリズマブ）：Amgen
• リルザブルチニブ（PRN1008/SAR444671）：Sanofi

第11章 IgG4-RD：主要7ヶ国市場分析

• 主な調査結果
• 市場見通し
• 主要な市場予測の前提条件
• コンジョイント分析
• 主要7ヶ国におけるIgG4-RDの総市場規模
• 主要7ヶ国におけるIgG4-RDの市場規模（治療法別）
• 米国
• EU4ヶ国と英国
• 日本

第12章 アンメットニーズ

第13章 SWOT分析

第14章 KOLの見解

第15章 市場アクセスと償還

• 米国
• EU4ヶ国と英国
• 日本
• IgG4-RDの償還

第16章 付録

第17章 DelveInsightのサービス内容

第18章 免責事項

第19章 DelveInsightについて

List of Tables

• Table 1: Summary of IgG4-RD Market and Epidemiology (2020-2034)
• Table 2: Differential Diagnosis of IgG4-RD, by Body Region or Organ
• Table 3: International Consensus Guidance Statements on the Treatment IgG4-RD, Voting Agreement, Level of Evidence, and Citations
• Table 4: The 2020 Revised Comprehensive Diagnostic (RCD) Criteria for IgG4-RD
• Table 5: The 2019 American College of Rheumatology/European League Against Rheumatism Classification Criteria for IgG4-RD
• Table 6: Diagnosis of Definitive and Probable Type 1 AIP Using ICDC
• Table 7: Level 1 and Level 2 Criteria for Type 1 AIP
• Table 8: Total Diagnosed Prevalent Cases of IgG4-RD in the 7MM (2020-2034)
• Table 9: Total Diagnosed Prevalent Cases of IgG4-RD in the United States (2020-2034)
• Table 10: Gender-specific Diagnosed Prevalent Cases of IgG4-RD in the United States (2020-2034)
• Table 11: Age-specific Diagnosed Prevalent Cases of IgG4-RD in the United States (2020-2034)
• Table 12: Total Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK (2020-2034)
• Table 13: Gender-specific Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK (2020-2034)
• Table 14: Age-specific Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK (2020-2034)
• Table 15: Total Diagnosed Prevalent Cases of IgG4-RD in Japan (2020-2034)
• Table 16: Gender-specific Diagnosed Prevalent Cases of IgG4-RD in the Japan (2020-2034)
• Table 17: Age-specific Diagnosed Prevalent Cases of IgG4-RD in the Japan (2020-2034)
• Table 18: Comparison of Emerging Drugs Under Development
• Table 19: Obexelimab (XmAb5871), Clinical Trial Description, 2025
• Table 20: UPLIZNA, Clinical Trial Description, 2025
• Table 21: Rilzabrutinib (PRN1008/SAR444671), Clinical Trial Description, 2025
• Table 22: Key Market Forecast Assumption of Current Treatment Options of IgG4-RD in the 7MM
• Table 23: Key Market Forecast Assumption of IgG4-RD in the US
• Table 24: Key Market Forecast Assumption of IgG4-RD in EU4 and the UK
• Table 25: Key Market Forecast Assumption of IgG4-RD in Japan
• Table 26: Total Market Size of IgG4-RD in the 7MM, in USD Million (2020-2034)
• Table 27: Market Size of IgG4-RD by Therapies in the 7MM, in USD Million (2020-2034)
• Table 28: Total Market Size of IgG4-RD in the US, in USD Million (2020-2034)
• Table 29: Market Size of IgG4-RD by Therapies in the US, in USD Million (2020-2034)
• Table 30: Total Market Size of IgG4-RD in EU4 and the UK, in USD Million (2020-2034)
• Table 31: Market Size of IgG4-RD by Therapies in EU4 and the UK, in USD Million (2020-2034)
• Table 32: Total Market Size of IgG4-RD in Japan, in USD Million (2020-2034)
• Table 33: Market Size of IgG4-RD by Therapies in Japan, in USD Million (2020-2034)

List of Figures

• Figure 1: Immunopathological Differences Among Four Clinical Phenotypes of IgG4-RD
• Figure 2: Pathophysiology of IgG4-RD
• Figure 3: Overview of Clinical Phenotypes in IgG4-RD
• Figure 4: Diagnosis Algorithm
• Figure 5: Treatment Algorithm in a Patient With IgG4-RD
• Figure 6: Diagnostic Algorithm Performance for Comprehensive Diagnostic Criteria for IgG4-RD
• Figure 7: Total Diagnosed Prevalent Cases of IgG4-RD in the 7MM (2020-2034)
• Figure 8: Total Diagnosed Prevalent Cases of IgG4-RD in the United States (2020-2034)
• Figure 9: Gender-specific Diagnosed Prevalent Cases of IgG4-RD in the United States (2020-2034)
• Figure 10: Age-specific Diagnosed Prevalent Cases of IgG4-RD in the United States (2020-2034)
• Figure 11: Total Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK (2020-2034)
• Figure 12: Gender-specific Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK (2020-2034)
• Figure 13: Age-specific Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK (2020-2034)
• Figure 14: Total Diagnosed Prevalent Cases of IgG4-RD in Japan (2020-2034)
• Figure 15: Gender-specific Diagnosed Prevalent Cases of IgG4-RD in Japan (2020-2034)
• Figure 16: Age-specific Diagnosed Prevalent Cases of IgG4-RD in Japan (2020-2034)
• Figure 17: Total Market Size of IgG4-RD in the 7MM, in USD Million (2020-2034)
• Figure 18: Market Size of IgG4-RD by Therapies in the 7MM, in USD Million (2020-2034)
• Figure 19: Total Market Size of IgG4-RD in the US, in USD Million (2020-2034)
• Figure 20: Market Size of IgG4-RD by Therapies in the US, in USD Million (2020-2034)
• Figure 21: Total Market Size of IgG4-RD in EU4 and the UK, in USD Million (2020-2034)
• Figure 22: Market Size of IgG4-RD by Therapies in EU4 and the UK, in USD Million (2020-2034)
• Figure 23: Total Market Size of IgG4-RD in Japan, in USD Million (2020-2034)
• Figure 24: Market Size of IgG4-RD by Therapies in Japan, in USD Million (2020-2034)
• Figure 25: Health Technology Assessment
• Figure 26: Reimbursement Process in Germany
• Figure 27: Reimbursement Process in France
• Figure 28: Reimbursement Process in Italy
• Figure 29: Reimbursement Process in Spain
• Figure 30: Reimbursement Process in the United Kingdom
• Figure 31: Reimbursement Process in Japan

Key Highlights:

• IgG4-RD can affect virtually any organ, with common presentations including the pancreas, bile ducts, salivary glands, lacrimal glands, orbits, kidneys, lungs, and retroperitoneum.
• The true prevalence of IgG4-RD is unknown. Given its relatively recent discovery, lack of widespread recognition, and frequently indolent presentation, it is likely that it is underrecognized and underreported. There is a male predominance, and the average age at diagnosis in large cohorts is in the thirties to fifties. However, classic cases have been observed in pediatric patients as well.
• There were nearly 148,970 diagnosed prevalent cases of IgG4-RD in 7MM in 2024. Among these, the US accounted for the highest number of diagnosed prevalent cases of IgG4-RD.
• Contrary to the scenario in the US and EU4, and the UK, there have been multiple studies conducted in Japan stating the diagnosed prevalence; therefore, based on 10-year cumulative diagnosed prevalence estimates from the National Database in Japan, along with evidence around drastic increase in the diagnosis of IgG4 related disease from 2015-2018, there were ~38,690 diagnosed cases in 2024 in Japan.
• Almost 20-30% of the diagnosed IgG4 patients do not undergo any treatment by systemic therapies, as they opt for either surgery or are under a watchful waiting strategy.
• There are no specific drugs to cure IgG4-RD due to unclear pathophysiology completely, and no approved therapies are available. The main treatment is corticosteroids like prednisone to manage inflammation and symptoms. If the disease relapses or doesn't respond, immunosuppressants like azathioprine or methotrexate may be used to reduce steroid dependence. Rituximab, an anti-CD20 monoclonal antibody, has also shown effectiveness in controlling inflammation and slowing disease progression. Glucocorticoids remain the first-line therapy.
• The current constrained pipeline features three emerging therapies: UPLIZNA (Amgen), obexelimab (Zenas BioPharma and Bristol Myers Squibb), and rilzabrutinib (Sanofi). Among these emerging therapies, UPLIZNA and obexelimab are expected to compete with each other strongly.
• The anticipated April 2025 approval of UPZILNA will transform the IgG4-RD market, marking the first-ever approved therapy for this underserved condition. It will redefine the treatment landscape, drive higher diagnosis rates, and shape commercial dynamics through pricing and physician adoption. However, market education, real-world validation, and future competition will influence its long-term impact.
• Rilzabrutinib, a Phase II therapy, represents a promising oral therapy targeting B-cell signaling pathways. If approved, it could disrupt the IV/SC biologic market by offering a more convenient, self-administered alternative.
• In 2024, the total market size of IgG4-RD in 7MM was nearly USD 170 million. The market size is expected to observe significant growth after the approval of potential emerging therapies in the pipeline.

DelveInsight's "IgG4-Related Disease (IgG4-RD) - Market Insights, Epidemiology and Market Forecast - 2034" report delivers an in-depth understanding of historical and forecasted epidemiology as well as market trends in the United States, EU4 (Germany, France, Italy, Spain) and the United Kingdom, and Japan. IgG4-RD market report provides current treatment practices, emerging drugs, market share of individual therapies, and current and forecasted 7MM market size from 2020 to 2034. The report also covers current treatment practices/algorithms and unmet medical needs to curate the best opportunities and assess the market's potential.

Geography Covered:

• The United States
• EU4 (Germany, France, Italy, and Spain) and the United Kingdom
• Japan

Study Period: 2020-2034

IgG4-RD Understanding and Treatment

IgG4-RD Overview

IgG4-RD is a systemic fibro inflammatory disease characterized by dense infiltration of IgG4-positive plasma cells in the affected tissue(s) with or without elevated plasma levels of IgG4. It is a chronic fibroinflammatory disorder affecting a wide range of organs. Elevation of serum IgG4 concentrations and abundant infiltration of IgG4-expressing plasma cells are key diagnostic features of this autoimmune disease. Although common organ involvement of IgG4-RD includes the salivary glands, pancreas, and bile duct, hepatic involvement is less well established.

IgG4-RD may be present in a certain proportion of patients with a wide variety of diseases, including Mikulicz's disease, autoimmune pancreatitis, hypophysitis, Riedel thyroiditis, interstitial pneumonitis, interstitial nephritis, prostatitis, lymphadenopathy, retroperitoneal fibrosis, inflammatory aortic aneurysm, and inflammatory pseudotumor.

IgG4-RD Diagnosis

IgG4-RD is challenging to diagnose since it may simultaneously affect several organs. Clinical, endoscopic, radiographic, and serological testing are required to diagnose the illness to examine organ involvement and end-organ damage (such as hormonal imbalances). A biopsy of the afflicted organ tissues, including the skin, is necessary for tissue diagnosis. Blood testing may reveal elevated serum IgG4 levels and peripheral eosinophilia.

Serum IgG4 concentration is the most important biomarker, with elevated levels found in up to 90% of patients, though this can vary. While a drop in IgG4 levels often signals treatment response, it may never return to normal, even in remission, due to long-lived plasma cells. Elevated IgG4 can also occur in other conditions, so its value must be considered within the broader clinical context. Other biomarkers, such as IgG1, IgE, eosinophilia, and complement levels (C3 and C4), can also reflect disease activity, with hypocomplementemia notably seen in IgG4-related kidney disease.

IgG4-RD Treatment

In individuals with IgG4-RD, treatment is not always essential, and in some asymptomatic instances, attentive waiting is appropriate. IgG4-RD, on the other hand, can induce major organ malfunction and failure, necessitating prompt therapy when essential organs are implicated or individuals exhibit symptoms.

According to the International Consensus Statement on the treatment of IgG4-RD, glucocorticoids represent the first-line therapy because they lead to dramatic clinical responses in most cases with pancreatic and extra-pancreatic diseases. Thus, a variety of glucocorticoid-sparing agents have been employed in different anatomical districts as remission-maintenance drugs (e.g., azathioprine, mycophenolate mofetil, methotrexate, cyclophosphamide, and bortezomib), with alternate results.

The use of steroid-sparing medications such as azathioprine, mycophenolate mofetil, and methotrexate are used to alleviate the adverse effects of glucocorticoids and to sustain remission; however, there is insufficient proof of their efficacy. Rituximab therapy is a more recent, promising alternative; it depletes CD20-positive plasmablast precursors; as there are fewer plasmablasts, IgG4 synthesis declines.

Since the earliest description of AIP, when a quick response to glucocorticoid treatment was noted as a distinctive finding, glucocorticoids have been regarded as the first-line therapy in IgG4-RD. The majority of IgG4-RD experts continue to believe that glucocorticoid is the first-line therapy for an active, untreated illness, according to the published consensus statement on the management of IgG4-RD. Prednisone is frequently used as the first step in remission induction. Most patients have a response to glucocorticoid treatment within a few days or weeks, and the majority of them reach remission within a few months.

IgG4-RD Epidemiology

As the market is derived using a patient-based model, the IgG4-RD epidemiology chapter in the report provides historical as well as forecasted epidemiology segmented by total diagnosed prevalent cases of IgG4-RD, gender-specific diagnosed prevalent cases of IgG4-RD, and age-specific diagnosed prevalent cases of IgG4-RD in the 7MM covering the United States, EU4 countries (Germany, France, Italy, Spain) and the United Kingdom, and Japan from 2020 to 2034.

• In 2024, the total diagnosed prevalent cases of IgG4-RD in the United States were approximately 56,800 cases, projected to increase during the forecast period (2025-2034).
• In 2024, gender-specific diagnosed prevalent cases accounted for approximately 39,100 and 17,700 cases for males and females, respectively, in the US.
• The total diagnosed prevalent cases of IgG4-RD in EU4 and the UK were approximately 53,550 in 2024. Males accounted for approximately 38,850 cases, and 14,750 cases in females.
• We have considered six age groups for the categorization of age groups, i.e., 0-17 years, 18-29 years, 30-44 years, 45-64 years, 65-74 years, and =75 years. As per our analysis, a higher percentage of diagnosed prevalent cases was observed in the age group =75 years in Japan. In 2024, the age-specific diagnosed prevalent cases of IgG4-RD in Japan were approximately 12,800 cases in the age group =75 years. The cases will increase during the forecast period (2025-2034).

Drug Chapters

The drug chapter segment of the IgG4-RD report encloses a detailed analysis of IgG4-RD marketed drugs and late-stage (Phase III and Phase II) pipeline drugs. It also helps understand the IgG4-RD clinical trial details, expressive pharmacological action, agreements and collaborations, approval and patent details, advantages and disadvantages of each included drug and the latest news and press releases.

Emerging Drugs

Obexelimab (XmAb5871): Zenas BioPharma and Bristol Myers Squibb

Obexelimab (XmAb5871) is a bifunctional monoclonal antibody designed to bind both CD19 and Fc?RIIb, which are broadly present across B-cell lineage, to inhibit the activity of cells that are implicated in many autoimmune diseases without depleting them. This unique mechanism of action and self-administered SC injection regimen may broadly and effectively address the pathogenic role of B-cell lineage in chronic autoimmune disease.

Currently, Zenas is conducting multiple Phase II and Phase III trials of obexelimab in several autoimmune diseases, including IgG4-RD, multiple sclerosis, systemic lupus erythematosus, and warm autoimmune hemolytic anemia. In August 2023, The Lancet Rheumatology published findings from a Phase II study evaluating obexelimab for the treatment of patients with IgG4-RD. Based on these results, a Phase III study in patients with IgG4-RD is ongoing to investigate further the efficacy and safety of obexelimab administered as an SC injection.

UPLIZNA (inebilizumab): Amgen

UPLIZNA is a humanized monoclonal antibody that causes targeted and sustained depletion of key cells that contribute to the underlying disease process (autoantibody-producing CD19+ B cells, including plasmablasts and some plasma cells). After two initial infusions, patients need one dose of UPLIZNA every 6 months. UPLIZNA is currently approved for the treatment of Neuromyelitis Optica. Currently, the drug has completed its Phase III results, and the FDA has granted a PDUFA action date of April 3, 2025.

UPLIZNA is anticipated to be the first approved cornerstone therapy for managing this complex and often debilitating condition, providing significant benefits to patients while addressing a critical gap in current treatment options for IgG4-RD. In the future, the drug could face competition with the approval of obexelimab, which operates through a bifunctional targeting mechanism of action.

Drug Class Insights

The current IgG4-RD emerging landscape has only three drugs. Among them, obexelimab (bifunctionally) and UPLIZNA target CD-19. Targeting CD19, a protein found in B cells, shows promise as a treatment for IgG4-RD by depleting B cells, which are thought to play a role in the disease's pathogenesis. Specifically, UPLIZNA, a CD19-targeted antibody, has demonstrated efficacy in reducing flares and achieving remission in IgG4-RD patients.

Market Outlook

As the etiology of IgG4-RD is unclear and still being studied, no particular medications can cure the disease. For people with IgG4-RD, there are no approved treatments on the market at this time. The criteria for identifying the disease caused by IgG4 levels and patient treatment recommendations were recently detailed in the guidelines released by the "International Consensus Guidance Statement on the Management and Treatment of IgG4-RD."

Patients with IgG4-RD that are active or untreated typically get glucocorticoids as their first line of therapy. Depending on the severity of the condition and the urgency of the situation, remission induction is frequently started with 30-40 mg/day of prednisone or a weight-adjusted dosage of 0.6 mg/kg of body weight each day.

In certain instances, conventional "Disease-Modifying Anti-Rheumatic Drugs" (DMARDs) are utilized to treat IgG4-RD. Plasmablasts are the first cell in any rheumatologic disorder to serve as an effective biomarker, and tailored therapy in B-cell employs total plasmablast concentration to track disease activity.

As numerous potential therapies are being investigated to manage IgG4-RD, it is safe to predict that the treatment space will experience significant reconstitution during the forecast period. However, the challenges of pricing and reimbursement accompanied by will decide the fate of all these pipeline therapies and the impact they will have on overall revenue generation.

Key players such as Zenas Biopharma, Amgen, and Sanofi are evaluating their lead candidates in different stages of clinical development, respectively. They aim to investigate their products to treat IgG4-RD.

• In 2024, the US captured the highest market share, i.e., nearly USD 90 million out of all the 7MM countries.
• EU4 and the UK accounted for nearly USD 80 million of the market share, and Germany accounted for the highest share in Europe in 2024.
• In Japan, the IgG4-RD market size accounted for nearly USD 6 million and is expected to increase at a significant CAGR during the forecast period (2025-2034).
• The lack of an established regulatory precedent and standardized endpoints for IgG4-RD trials poses approval risks. Additionally, payer resistance to high-cost biologics may slow adoption, especially if off-label rituximab remains a cost-effective alternative. However this will not be an issue in Japan as rituximab is not yet permitted for use to treat IgG4-RD in Japan due to Japanese medical insurance reasons.

Key Updates

• In November 2024, Zenas BioPharma announced the completion of its targeted enrollment for the Phase III INDIGO trial of its lead product candidate, obexelimab, for the treatment of patients with IgG4-RD.
• In November 2024, Zenas BioPharma announced that the company anticipates reporting topline results for the INDIGO trial by the end of 2025.
• In August 2024, Amgen announced that the US FDA had granted Breakthrough Therapy Designation (BTD) to UPLIZNA for the treatment of IgG4-RD based on data from the MITIGATE study.
• In February 2025, Amgen announced that the FDA had accepted the regulatory submission for the Phase III MITIGATE study under priority review, with a PDUFA action date of April 3, 2025.

IgG4-RD Drugs Uptake

This section focuses on the uptake rate of potential drugs expected to be launched in the market during 2020-2034. The landscape of IgG4-RD treatment has experienced a profound transformation with the uptake of novel drugs. These innovative therapies are redefining standards of care. Furthermore, the increased uptake of these transformative drugs is a testament to the unwavering dedication of physicians, oncology professionals, and the entire healthcare community in their tireless pursuit of advancing cancer care. This momentous shift in treatment paradigms is a testament to the power of research, collaboration, and human resilience.

IgG4-RD Pipeline Development Activities

The report provides insights into different therapeutic candidates in Phase III, Phase II/III, Phase II, Phase I/II, and Phase I. It also analyzes key players involved in developing targeted therapeutics.

Pipeline Development Activities

The report covers detailed information on collaborations, acquisitions and mergers, licensing, and patent details for IgG4-RD emerging therapies.

KOL Views

To keep up with current market trends, we take KOLs and SMEs' opinions working in the domain through primary research to fill the data gaps and validate our secondary research. Some of the leaders like MD, PhD, Research Project Manager, Director, and others. Their opinion helps to understand and validate current and emerging therapies and treatment patterns or IgG4-RD market trends. This will support the clients in potential upcoming novel treatments by identifying the overall scenario of the market and the unmet needs.

Delveinsight's analysts connected with 20+ KOLs to gather insights; however, interviews were conducted with 10+ KOLs in the 7MM. Centers such as the Massachusetts General Hospital, Hopital La Timone, Harvard Medical School, Hospital Universitari Vall d'Hebron, Tokyo Metropolitan Cancer and Infectious Diseases Center Komagome Hospital, etc., were contacted. Their opinion helps understand and validate IgG4-RD epidemiology and market trends.

Qualitative Analysis

We perform qualitative and market Intelligence analysis using various approaches, such as SWOT and conjoint analysis. In the SWOT analysis, strengths, weaknesses, opportunities, and threats in terms of disease diagnosis, patient awareness, patient burden, competitive landscape, cost-effectiveness, and geographical accessibility of therapies are provided. These pointers are based on the analyst's discretion and assessment of the patient burden, cost analysis, and existing and evolving treatment landscape.

The analyst analyzes multiple emerging therapies based on relevant attributes such as safety, efficacy, frequency of administration, route of administration, and order of entry.

In efficacy, the trial's primary and secondary outcome measures are evaluated.

Further, the therapies' safety is evaluated wherein the acceptability, tolerability, and adverse events are majorly observed, and it sets a clear understanding of the side effects posed by the drug in the trials.

Market Access and Reimbursement

The cost of newly approved medications is usually high, and because of it, patients escape from proper treatment or opt for off-label and cheap medications. It affects market access to newly launched medications, and reimbursement is crucial. The decision to reimburse often comes down to the drug's price relative to the benefit it produces in treated patients. Market access and reimbursement options can differ depending on regulatory status, target population size, the setting of care, unmet needs, the magnitude of incremental benefit claims, and costs.

The report further provides detailed insights on the country-wise accessibility and reimbursement scenarios, cost-effectiveness scenario of approved therapies, programs making accessibility easier and out-of-pocket costs more affordable, insights on patients insured under federal or state government prescription drug programs, etc.

Scope of the Report:

• The report covers a descriptive overview of IgG4-RD, explaining its causes, signs and symptoms, pathogenesis, and currently available therapies.
• Comprehensive insight has been provided into IgG4-RD epidemiology and treatment.
• Additionally, an all-inclusive account of both the current and emerging therapies for IgG4-RD is provided, along with the assessment of new therapies which will have an impact on the current treatment landscape.
• A detailed review of the IgG4-RD market, historical and forecasted, is included in the report, covering the 7MM drug outreach.
• The report provides an edge while developing business strategies by understanding trends shaping and driving the 7MM IgG4-RD market.

IgG4-RD Report Insights

• Patient population
• Therapeutic approaches
• IgG4-RD pipeline analysis
• IgG4-RD market size and trends
• Market opportunities
• Impact of upcoming therapies

IgG4-RD Report Key Strengths

• Ten years forecast
• 7MM coverage
• IgG4-RD epidemiology segmentation
• Key cross competition
• Highly analyzed market
• Drugs uptake

IgG4-RD Report Assessment

• Current treatment practices
• Unmet needs
• Pipeline product profiles
• Market attractiveness
• Qualitative analysis (SWOT and conjoint analysis)

FAQs:

• What was the IgG4-RD market share (%) distribution in 2020, and what would it look like in 2034?
• What would be the IgG4-RD total market size as well as market size by therapies across the 7MM during the study period (2020-2034)?
• Which country will have the largest IgG4-RD market size during the study period (2020-2034)?
• What are the disease risks, burdens, and unmet needs of IgG4-RD?
• What is the historical IgG4-RD patient pool in the United States, EU4 (Germany, France, Italy, and Spain) and the UK and Japan?
• What will be the growth opportunities across the 7MM concerning the patient population of IgG4-RD?
• How many emerging therapies are in the mid-stage and late stage of development for the treatment of IgG4-RD?
• What are the key collaborations (Industry-Industry, Industry-Academia), Mergers and acquisitions, and licensing activities related to IgG4-RD therapies?
• What are the recent novel therapies, targets, mechanisms of action, and technologies developed to overcome the limitations of existing therapies?
• What are the clinical studies going on for IgG4-RD and their status?
• What are the key designations that have been granted for the emerging therapies for IgG4-RD?

Reasons to Buy:

• The report will help in developing business strategies by understanding trends shaping and driving IgG4-RD.
• To understand the future market competition in the IgG4-RD market and an Insightful review of the SWOT analysis of IgG4-RD.
• Organize sales and marketing efforts by identifying the best opportunities for IgG4-RD in the US, EU4 (Germany, France, Italy, and Spain), the United Kingdom, and Japan.
• Identification of strong upcoming players in the market will help in devising strategies that will help in getting ahead of competitors.
• Organize sales and marketing efforts by identifying the best opportunities for the IgG4-RD market.
• To understand the future market competition in the IgG4-RD market.

Table of Contents

1. Key Insights

2. Report Introduction

3. Executive Summary

4. Key Events

5. Epidemiology and Market Forecast Methodology

6. IgG4-RD Market Overview at a Glance

• 6.1. Market Share (%) Distribution by Therapies of IgG4-RD in 2024
• 6.2. Market Share (%) Distribution by Therapies of IgG4-RD in 2034

7. Disease Background and Overview

• 7.1. Introduction
• 7.2. Clinical Phenotype
• 7.3. Histology Related to IgG4-RD
• 7.4. Pathogenesis Related to IgG4-RD
• 7.5. Disease Subtypes and Clinical Manifestations
• 7.6. Signs and Symptoms Related to IgG4-RD
• 7.7. Diagnostic Evaluation of IgG4-RD
  • 7.7.1. Biomarkers of Disease Activity and Damage
  • 7.7.2. Differential Diagnosis
  • 7.7.3. Diagnosis Algorithm
• 7.8. Treatment and Management for IgG4-RD
  • 7.8.1. Treatment and Management Algorithm
• 7.9. Guidelines, Recommendations, and Management for IgG4-RD
  • 7.9.1. International Consensus Guidance Statement on the Management and Treatment of IgG4-RD (2015)
  • 7.9.2. European Guideline on IgG4-related Digestive Disease-UEG and SFG Evidence-based Recommendations (2020)
  • 7.9.3. The 2020 Revised Comprehensive Diagnostic (RCD) Criteria for IgG4-RD (2021)
  • 7.9.4. American College of Rheumatology (ACR) and the European League Against Rheumatism (EULAR) Guidelines for Diagnosis (2020)
  • 7.9.5. Current Approach to the Diagnosis of IgG4-RD: A Combination of Comprehensive Diagnostic and Organ-specific Criteria (2017)

8. Epidemiology and Patient Population of IgG4-RD in the 7MM

• 8.1. Key Findings
• 8.2. Assumptions and Rationales
• 8.3. Total Diagnosed Prevalent Cases of IgG4-RD in the 7MM
• 8.4. The United States
  • 8.4.1. Total Diagnosed Prevalent Cases of IgG4-RD in the United States
  • 8.4.2. Gender-specific Diagnosed Prevalent Cases of IgG4-RD in the United States
  • 8.4.3. Age-specific Diagnosed Prevalent Cases of IgG4-RD in the United States
• 8.5. EU4 and the UK
  • 8.5.1. Total Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK
  • 8.5.2. Gender-specific Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK
  • 8.5.3. Age-specific Diagnosed Prevalent Cases of IgG4-RD in EU4 and the UK
• 8.6. Japan
  • 8.6.1. Total Diagnosed Prevalent Cases of IgG4-RD in Japan
  • 8.6.2. Gender-specific Diagnosed Prevalent Cases of IgG4-RD in Japan
  • 8.6.3. Age-specific Diagnosed Prevalent Cases of IgG4-RD in Japan

9. Patient Journey

10. Emerging Drugs

• 10.1. Key Cross Competition
• 10.2. Obexelimab (XmAb5871): Zenas BioPharma and Bristol Myers Squibb
  • 10.2.1. Product Description
  • 10.2.2. Other Development Activity
  • 10.2.3. Clinical Development
    • 10.2.3.1. Clinical Trial Information
  • 10.2.4. Safety and Efficacy
  • 10.2.5. Analyst Views
• 10.3. UPLIZNA (inebilizumab): Amgen
  • 10.3.1. Product Description
  • 10.3.2. Other Development Activity
  • 10.3.3. Clinical Development
    • 10.3.3.1. Clinical Trial Information
  • 10.3.4. Safety and Efficacy
  • 10.3.5. Analyst View
• 10.4. Rilzabrutinib (PRN1008/SAR444671): Sanofi
  • 10.4.1. Product Description
  • 10.4.2. Other Development Activity
  • 10.4.3. Clinical Development
    • 10.4.3.1. Clinical Trial Information
  • 10.4.4. Analyst View

11. IgG4-RD: Seven Major Market Analysis

• 11.1. Key Findings
• 11.2. Market Outlook
• 11.3. Key Market Forecast Assumptions
  • 11.3.1. Cost Assumptions and Rebate
  • 11.3.2. Pricing Trends
  • 11.3.3. Analogue Assessment
  • 11.3.4. Launch Year and Therapy Uptake
• 11.4. Conjoint Analysis
• 11.5. Total Market Size of IgG4-RD in the 7MM
• 11.6. Market Size of IgG4-RD by Therapies in the 7MM
• 11.7. The United States
  • 11.7.1. Total Market Size of IgG4-RD in the US
  • 11.7.2. Market Size of IgG4-RD by Therapies in the US
• 11.8. EU4 and the UK
  • 11.8.1. Total Market Size of IgG4-RD in the EU4 and the UK
  • 11.8.2. Market Size of IgG4-RD by Therapies in EU4 and the UK
• 11.9. Japan
  • 11.9.1. Total Market Size of IgG4-RD in Japan
  • 11.9.2. The Market Size of IgG4-RD by Therapies in Japan

12. Unmet Needs

13. SWOT Analysis

14. KOL Views

15. Market Access and Reimbursement

• 15.1. United States
  • 15.1.1. Centre for Medicare and Medicaid Services (CMS)
• 15.2. EU4 and the UK
  • 15.2.1. Germany
  • 15.2.2. France
  • 15.2.3. Italy
  • 15.2.4. Spain
  • 15.2.5. United Kingdom
• 15.3. Japan
  • 15.3.1. MHLW
• 15.4. Reimbursement for IgG4-RD

16. Appendix

• 16.1. Bibliography
• 16.2. Report Methodology

17. DelveInsight Capabilities

18. Disclaimer

19. About DelveInsight