Dose Escalation Study to Evaluate an Experimental New Treatment (CALY-002) in Healthy Subjects and Subjects With Celiac Disease and Eosinophilic Esophagitis

Inclusion Criteria:

• Part A. Healthy Subjects:

1. Male or female aged between 18 and 50 years (both inclusive)
2. Must be healthy on the basis of the physical examination findings, clinicallaboratory tests, medical history, vital signs, and cardiac monitoring (normal 12lead electrocardiogram [ECG] results) performed at screening, in the opinion ofthe investigator

• Part B. Subjects with Celiac Disease (CeD):

1. Male or female ≥ 18 years of age.
2. Diagnosis of CeD by intestinal biopsy at least 12 months prior to screening asconfirmed by medical records.
3. No histological signs of active CeD at screening
4. Gluten-free diet (GFD) for at least 12 consecutive months prior to screening
5. Willing to undertake a gluten challenge (intake of approximately 3 g of glutendaily) for 56 consecutive days
6. Must be healthy on the basis of physical examination findings, clinicallaboratory tests, medical history, vital signs, and cardiac monitoring (normal 12lead ECG results) performed at screening, in the opinion of the investigator.

• Part C. Subjects with Eosinophilic Esophagitis (EoE):

1. Male or female ≥ 18 years of age.
2. Must have endoscopically confirmed and documented diagnosis of EoE
3. Should exhibit active symptoms of dysphagia with more than 3 episodes ofdysphagia during a period of 2 weeks during screening.
4. Must have clinically active disease
5. Must have had a relapsed EoE or did not respond after first line therapy
6. Subject must be healthy on the basis of physical examination findings, clinicallaboratory tests, medical history, vital signs, and cardiac monitoring (normal 12lead ECG results) performed at screening, in the opinion of the investigator.

Exclusion Criteria:

• Part A. Healthy Subjects excluded:

1. Any significant medical condition, laboratory abnormality, or psychiatric illness
2. Any condition that confounds the ability to interpret data from the study.
3. Currently receiving or has been previously treated with a biologic agent.
4. History of anaphylactic reactions to protein therapeutics.
5. Has current or recent (within 4 weeks prior to screening) signs or symptoms ofinfection that require parenteral antibiotic administration.
6. Has evidence of SARS-CoV-2 infection and/or subject Is deemed at risk for thecoronavirus disease (COVID-19)
7. Has had major surgery (including joint surgery) within 8 weeks prior to screeningand hospitalisation for a clinically relevant event within the 4 weeks prior toscreening.

• Part B. Subjects with Celiac Disease (CeD) excluded:

1. A concurrent active autoimmune disease (other than CeD) that requires systematictreatment with immunosuppressants.
2. Has severe complication of CeD such as refractory CeD.
3. Has active (microscopic) colitis with clinical signs of diarrhoea and abdominalpain.
4. Is currently receiving or has been previously treated with a biologic agent.
5. Has a history of anaphylactic reactions to protein therapeutics.
6. Subject has evidence of SARS-CoV-2 infection and/or subject is deemed at risk forthe coronavirus disease (COVID-19).

• Part C: Subjects with Eosinophilic Esophagitis (EoE) excluded:

1. Has a hyper-eosinophilic syndrome.
2. Has a concurrent active autoimmune disease (other than EoE) that requirestreatment with immunosuppressants.
3. Has active (microscopic) colitis with clinical signs of diarrhoea and abdominalpain.
4. Currently receiving or has been previously treated with a biologic agent.
5. Has a history of anaphylactic reactions to protein therapeutics.
6. Subject has evidence of SARS-CoV-2 infection and/or subject is deemed at risk forthe coronavirus disease (COVID-19).