Evaluation of an Oral Anti-TNF Antibody in Patients With Active Ulcerative Colitis

There is a significant unmet medical need for effective oral pharmacologic therapies for
inflammatory bowel diseases such as ulcerative colitis. Current anti-TNF therapies,
including infliximab and adalimumab, are effective treatments for these conditions, but they
must be administered by intravenous or subcutaneous injection. The major safety concerns
associated with the use of injectable anti-TNF therapies are infection, demyelinating
disease, and lymphoma, all of which are the result of systemic exposure. These uncommon but
serious side effects have limited the use of systemic anti-TNF antibody therapy to patients
with severe disease that have failed to respond to first-line treatments.

AVX-470 is purified immunoglobulin (Ig) from the colostrum (early milk) of cows immunized
with recombinant human tumor necrosis factor (rhTNF). AVX-470 is formulated in
delayed-release enteric-coated capsules designed to protect the capsule contents from
gastric acids following oral administration and to provide localized delivery to sites of
inflammation in the distal intestine. Prior clinical experience with bovine Ig therapies in
other human diseases suggests that AVX-470 will not be absorbed to any significant extent,
meaning that systemic exposure could be minimized. The development of oral anti-TNF therapy
targeting local intestinal disease activity might reduce the risks associated with
injectable anti-TNF therapy and allow the convenience of oral dosing.

The present study is a first-in-human, Phase 1 clinical study. It is primarily intended to
evaluate the safety and tolerability of multiple doses of AVX-470 administered orally to
patients with active ulcerative colitis.

Animal models of ulcerative colitis using a mouse-specific TNF antibody derived from bovine
colostrum demonstrated a 50% or more reduction in tissue TNF, TNF-messenger ribonucleic acid
(mRNA), interleukin (IL)-6 mRNA, and myeloperoxidase and lowering of colonic inflammatory
activity. Twenty-eight-day toxicology studies demonstrated no clinical or histologic
findings in exposures above the intended clinical dose range.

Inclusion Criteria:

- Men or women aged 18 75, inclusive

- Established diagnosis of ulcerative colitis involving the sigmoid colon or proximal
segments of bowel

- Total Mayo score between 5-12, inclusive, with endoscopic subscore of the Mayo score
≥ 2 and > 15 cm of involvement beyond the anal verge

Exclusion Criteria:

- Women with a positive pregnancy test, who are breastfeeding, or who intend to become
pregnant during the course of the study

- Diagnosis of Crohn's disease, microscopic colitis or indeterminate colitis

- Presence of ileostomy or colostomy, or history of prior colon resection

- Patients with planned hospitalization or surgery during the course of the study

- Known allergy to milk proteins, red meat or cornstarch

- Stools positive for enteric infection, including parasitic, or C. difficile toxin
within 28 days of screening

- Documented presence of Hetatitis B (HBsAg), Hepatitis C (HCV), or HIV

- Presence of dysplasia of any grade on colonoscopic biopsies

- Treatment for cancer (excluding non-melanomatous cancer of the skin or cervical
carcinoma in situ) or lymphoproliferative disorder (including lymphoma) within 5
years

- History of tuberculosis (TB) or Listeria infection, or known exposure to another
person with active TB disease within 12 weeks of screening; or history of past or
current infection with different opportunistic infections

- History of TNF inhibitor (infliximab, adalimumab or certolizumab pegol) use with
primary treatment failure. Secondary treatment failures due to intolerance, allergic
reaction, or loss of response will not constitute a basis for exclusion. Oral
immunosuppressives, mesalamine, and corticosteroids (up to 20mg of prednisone per
day) will be permitted so long as these medications are stable for defined periods of
time before study participation commences.