Fulminant Colitis Following Rituximab Therapy.

Abstract

Rituximab (RTX; Rituxan, Genentech) is the clinical formulation of a murine immunoglobulin G (IgG) 1 monoclonal anti-CD20 antibody and is widely used in the initial treatment of CD20-positive hematologic malignancies and a variety of autoimmune disorders. Rarely, fulminant colitis has been reported with the use of RTX (Table).1-7 We report a patient who developed 2 episodes of fulminant colitis after 2 infusions with RTX for the treatment of disseminated B-cell marginal lymphoma. The first episode of colitis required subtotal colectomy, and the second episode required completion proctectomy. Table. Cases of RTX and Colitis A 62-year-old woman presented in October 2002 with a left lower abdominal wall mass. The patient’s peripheral blood smear showed atypical lymphocytes. After an excisional biopsy and histologic and flow cytometry, the patient was diagnosed with marginal zone B-cell lymphoma. The patient was offered a combination treatment of CHOP chemotherapy with RTX or RTX alone. The patient decided to undergo therapy with RTX alone. After receiving several cycles of RTX therapy from 2002 to 2005 and another 4 doses in September 2005, the patient developed severe abdominal pain and diarrhea. Her stool studies were negative for an infectious etiology. A computed tomography scan showed diffuse wall thickening and distention of the entire colon with areas of pneumatosis. The patient’s condition deteriorated and required a subtotal colectomy with ileostomy. Three months later, the ileostomy was closed. In September 2010, after receiving a second course of 4 cycles of RTX therapy for recurrent lymphoma, the patient developed severe abdominal pain and diarrhea. Her stool studies were again negative for an infectious source. Diffuse severe colitis was noted on a sigmoidoscopy. The biopsies revealed severely inflamed tissue (Figure). The patient’s clinical course worsened later, requiring a proctectomy. Figure. Colonic mucosa, submucosa, and muscularis propria on the left show the lateral edge of an ulcer on the right that undermines residual mucosa and submucosa. Ulceration extends to the level of the muscularis propria with partial penetration of the ulcer ...