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Draft guidelines for the clinical evaluation of drugs for ulcerative colitis.

Ulcerative colitis is a chronic, idiopathic inflammatory disease of the colon characterized by diffuse, continuous, superficial, acute, and chronic inflammation beginning at the anal verge and extending proximal to a variable extent in individual patients. The inflammatory features remain superficial (above the lamina propria) except in the most severe situations in which the inflammation extends through the muscle layers, producing toxic megacolon. Within the involved segment of colon the inflammatory features are uniform, although healing may occur in a patchy distribution. Pathologic features include a spectrum of inflammatory changes ranging from normal-appearing colonic mucosa proximal to the demarcation of inflammation to crypt distortion without acute inflammatory cells (polymorphonuclear leukocytes), excess chronic inflammatory infiltrate (generally lymphocytes), invasion of crypt epithelium by polymorphonuclear leukocytes, extrusion of pol ymorphonuclear leukocytes into crypts (crypt abscesses), and total disruption of the epithelial lining (mucosal ulceration). Healing of acute inflammation is first manifest by a reduction in the acute inflammatory infiltrate (polymorphonuclear leukocytes), regenerative changes within the crypt epithelium, and a gradual repletion of mucocytes, although the grandular architecture may remain distorted with irregular or branching glands in the absence of acute or excessive chronic inflammation. Dysplastic changes must be differentiated from the effects of active inflammation or regeneration. The spectrum of endoscopic changes corresponds to the underlying inflammatory reaction. Proximal to the demarcation of inflammation the colonic mucosa is intact, glistening, with a normal branching, submucosal, vascular pattern. In healed ulcerative colitis, the mucosa remains intact, although the vascular pattern may appear distorted with irregular submucosal vessels. Progressive inflammatory features include mucosal edema obscuring the submucosal vessels, erythema corresponding to mucosal capillary dilatation, fine to coarse granularity and friability (hemorrhage that may be either induced or spontaneous), and pinpoint to extensive mucosal ulceration. Extrusion of mucopus may be absent, patchy, or confluent. Similar to the histologic features, within a segment of ulcerative colitis the endoscopic features are relatively constant, although in the healing phase the mucosa may regenerate in an irregular distribution. Postinflammatory (pseudo) polyps may persist amid regenerated mucosa and do not correlate with adjacent histologic healing. The clinical features of ulcerative colitis vary according to the spectra of severity of acute inflammation and proximal extent of mucosal involvement. The passage of blood and/or mucus, in general, corresponds to the degree of rectal inflammation. Other associated clinical features of distal inflammation include tenesmus, abdominal cramping, and incontinence. Diarrhea is a subjective complaint that must be defined objectively (e.g., trips to the toilet, number of bowel movements or evacuations, evacuation of stool, liquidity of stool, fecal volume, etc.). The number of bowel movements may depend on the degree of inflammation within the rectum, rectal compliance, or proximal extent of inflammation. (For example, patients with mild, distal proctitis may be constipated, but pass blood with each bowel movement, whereas patients with extensive colitis may have liquid stool without bleeding). Abdominal cramping is a common symptom, although abdominal pain (and tenderness) is an uncommon complaint suggesting transmural extension. Ulcerative colitis may be accompanied by systemic manifestations including fever, tachycardia, orthostasis, nausea, and vomiting in the presence of more severe or extensive inflammatory changes. Extraintestinal features include occular inflammation, central or peripheral arthropathies, a spectrum of hepatic inflammatory changes that do not uniformly correspond to the degree of colonic inflammation. In children, growth retardation, delayed sexual development, arthritis, or fever of undetermined origin may be presenting features. Ulcerative colitis must be distinguished from other inflammatory conditions of the colon. Crohn’s disease of the colon is distinguished from ulcerative colitis by the presence of focal, asymmetric inflammatory changes inducing aphthoid ulcers, linear ulcerations, fissures and fistula, hemorrhoids, small intestinal inflammation, and transmural and/or granulomatous pathologic changes.