# Section 2B: Disease-Area Market & Epidemiology Context

*A market report needs the market. This section sizes the three anchor
indications — type 1 diabetes, celiac disease, and eosinophilic esophagitis —
on prevalence, current standard of care, treatment burden, and commercial scale,
to frame where an antigen-specific tolerance therapy would compete.*

---

## 2B.1 Type 1 diabetes (T1D) — the proving ground

- **Prevalence:** ~1.3–1.8 million people in the US; ~9 million worldwide.
  Incidence rising ~2–4%/year. Roughly **90% of new cases have no family
  history**, which is why family-history-limited screening misses most future
  patients — the single most important structural fact behind Tzield's uptake
  problem.
- **Standard of care:** lifelong exogenous insulin (pumps, pens, closed-loop
  systems), continuous glucose monitoring. Highly effective at survival but a
  relentless daily-management burden; no approved therapy halts the underlying
  autoimmunity except Tzield's delay-of-onset indication.
- **Market scale:** the T1D drug market is large and growing; GlobalData projects
  the 7-major-market T1D drug market to reach **~$9.9 billion by 2033**, within
  which Tzield could become a top product (~$4.8B forecast) *if* screening
  scales.
- **Why it led:** defined autoantigens (insulin, GAD65, IA-2, ZnT8), a
  measurable biomarker (C-peptide), a mature at-risk-screening research
  infrastructure (TrialNet), and deep-pocketed advocacy (JDRF/Breakthrough T1D).
  Every ingredient an antigen-specific program wants.

## 2B.2 Celiac disease — the cleanest antigen, the hardest endpoint

- **Prevalence:** ~1% of the population (US ~2–3 million diagnosed; many more
  undiagnosed). Strongly HLA-linked: **~90–95% carry HLA-DQ2.5**, the rest
  mostly HLA-DQ8 — an unusually clean genetic-restriction picture.
- **Standard of care:** a **lifelong strict gluten-free diet (GFD)** — the only
  management option. But the GFD is incompletely protective (inadvertent
  exposure is common), socially burdensome, and does not fully heal the mucosa in
  a substantial fraction of patients. This unmet need is precisely what the
  antigen-specific programs target.
- **Market scale:** no approved drug exists for celiac disease — the entire
  therapeutic market is greenfield. Multiple mechanisms compete (tolerance
  vaccines, gluten-degrading enzymes, tight-junction modulators, IL-15 and other
  biologics). A first-approved non-dietary therapy would define the category.
- **Why it led, and why it's hard:** one antigen (gluten), one dominant
  restriction element, one measurable T-cell response — ideal for antigen-specific
  design. But the clinical endpoint (symptom protection under gluten challenge)
  proved treacherous, as Nexvax2 showed.

## 2B.3 Eosinophilic esophagitis (EoE) — the target indication

- **Prevalence:** rising rapidly; current estimates ~1 in 2,000 people
  (~0.5–1 per 1,000), with higher rates in children, males, and atopic
  individuals. Incidence and prevalence have climbed steeply over two decades —
  partly true increase, partly recognition.
- **Standard of care:** three pillars, none curative — (i) **proton-pump
  inhibitors**; (ii) **swallowed topical corticosteroids** (budesonide oral
  suspension approved); (iii) **dietary elimination** (empiric 6-food or targeted
  elimination — itself a major quality-of-life burden); and now (iv)
  **dupilumab** (anti-IL-4Rα, approved for EoE in 2022) and emerging IL-5/IL-13
  biologics. All require **indefinite** administration; stopping typically
  relapses.
- **Treatment burden:** repeated **endoscopy with biopsy** for monitoring
  (invasive, requires sedation), the social and nutritional toll of elimination
  diets, the fear of **food impaction** (acute obstruction requiring emergency
  removal), and progression to **fibrostenosis** — irreversible esophageal
  narrowing — if inadequately controlled.
- **Market scale:** the EoE therapeutics market is expanding quickly on the back
  of dupilumab's approval and a crowded biologic pipeline, but every entrant so
  far is an **anti-inflammatory requiring chronic dosing**. There is **no
  antigen-specific / tolerance-inducing therapy** — the differentiated whitespace.
- **Why EoE is the hardest antigen problem in this report:** the drivers are
  **food allergens** that vary by patient (milk, wheat, egg, soy most common),
  often multiple simultaneously, with a mixed Th2/allergic mechanism distinct
  from the Th1-dominated celiac/T1D biology. A pMHC tolerance vaccine must solve
  antigen selection first — the direct link to this program's omics and
  pMHC/HLA analysis streams.

---

## 2B.4 Comparative snapshot

| Dimension | Type 1 diabetes | Celiac disease | Eosinophilic esophagitis |
|---|---|---|---|
| Driving antigen | Self (insulin, GAD65, IA-2, ZnT8) | Gluten (dietary) | Food allergens (milk, wheat, egg, soy) — plural, variable |
| HLA restriction | HLA-DR3/DR4-DQ2/DQ8 | HLA-DQ2.5 (~90%) / DQ8 | HLA associations weaker/less defined |
| Immune polarity | Th1 / cytotoxic | Th1 (DQ2.5-restricted CD4) | Th2 / allergic (eosinophilic) |
| Biomarker | C-peptide, autoantibodies | Anti-tTG, gluten-specific T cells | Esophageal eosinophil count (histology) |
| Standard of care | Insulin (lifelong) | Gluten-free diet (only option) | PPI / steroids / diet / dupilumab (all chronic) |
| Approved tolerance therapy | Tzield (delay only; nonspecific) | None | None |
| Antigen-specific opportunity | Proven modality entry | Greenfield, active pipeline | **Greenfield + no competitor = whitespace** |

The pattern is clear: **EoE combines the strongest commercial whitespace with the
hardest antigen-selection problem.** Solving antigen selection — the project's
core scientific task — is what converts the whitespace into a program.