An Open-Label Trial of Losartan Potassium in Participants With Eosinophilic Esophagitis (EoE)

The purpose of this research study is to test the safety of Losartan potassium to see what
effects (good and bad) it has on participants and their Eosinophilic Esophagitis (EoE). If a
subject has Connective Tissue Disease (CTD) the researchers want to see what effects (good or
bad) Losartan has on EoE.

EoE is an inflammatory disease in the esophagus (the tube leading from the mouth to the
stomach) that is typically triggered by exposure to certain things in food. Connective Tissue
Disorders (CTDs) are disorders that affect the connective tissues in the body, such as fat,
bone, and cartilage.

Eosinophils release a protein called TGF-beta. Losartan may decrease the amount of the
protein and therefore help EoE and CTD.

Losartan is a drug that is approved by the United States Food and Drug Administration (FDA)
for use in adults and children over 6 years of age who have high blood pressure. This
medication has not been studied in people with EoE.

Inclusion Criteria:

- Written informed consent/assent

- confirmed, active EoE (at Screening or within 12 weeks prior to enrollment)

- does or does not have diagnosis of a connective tissue disorder (CTD)

- has been on a high dose of proton pump inhibitor (PPI) for at least 8 weeks prior to a
diagnostic endoscopy of EoE without histologic resolution (i.e., ≥ 15
eosinophils/HPF).

- maintain the same diet, swallowed steroid and PPI therapies throughout the duration of
the study

- female participants must be either:

1. of non-childbearing potential (pre-menarchal or surgically sterile with
documentation). OR

2. have a negative urine pregnancy test at screening and at each monthly study
visit.

Exclusion Criteria:

- Any past or planned cardiac surgery.

- An aortic root Z-score ≥ 3.0 on a previous echocardiogram.

- Intolerance to losartan

- A mean blood pressure measurement (both systolic and diastolic) at screening that is
below the 2nd percentile for his/her age

- Renal dysfunction

- Another disorder that causes esophageal eosinophilia (e.g., hypereosinophilic
syndrome, Churg Strauss vasculitis, eosinophilic granuloma, or a parasitic infection).

- A diagnosis of hepatic insufficiency (e.g., liver failure, history of liver
transplantation or persistent liver transaminase elevation).

- A history of abnormal gastric or duodenal biopsy or documented gastrointestinal
disorders (e.g., Celiac Disease, Crohn's disease or Helicobacter pylori infection),
not including chronic gastritis, chronic duodenitis, mucosal eosinophilia or other
eosinophilic gastrointestinal disorders (EGIDs).

- Use of anti-IgE monoclonal antibody (mAb), anti-tumor necrosis factor [TNF] mAb,
anti-IL-5 agents, or anti-IL-13 within 6 months prior to study entry

- Use of methotrexate, cyclosporine, interferon α, or other systemic immunosuppressive
or immunomodulating agents within 3 months prior to the screening visit.

- A stricture during endoscopy procedure that prevents passage of the endoscope

- Taking or is planning to take an angiotensin receptor blocker (ARB),
angiotensin-converting enzyme inhibitor (ACEI), beta blocker (BB), or calcium-channel
blocker therapy at the screening visit or at any time during the study or has been
taking any of these medications for 3 months prior to the screening visit.

- Taking or planning to take hydrochlorothiazide, digoxin, warfarin, cimetidine,
phenobarbital, rifampin, or fluconazole.

- taking or planning to take potassium supplements or salt substitutes containing
potassium.

- A female participant who is pregnant or nursing or, if of childbearing potential, is
not using a medically accepted, effective method of birth control (e.g., condom,
oral/injectable/subcutaneous contraceptive, intrauterine device, or sexual
abstinence).

- Participated/participating in any investigative drug or device study within 30 days
prior to study entry.

- Participated/participating in any investigative biologics study within 3 months prior
to study entry.

- Unable to be confirmed, active EoE (at Screening or within 12 weeks prior to
enrollment)