A phase I study of visilizumab, a humanized anti-CD3 monoclonal antibody, in severe steroid-refractory ulcerative colitis.
ABSTRACT To evaluate the safety and biological activity of visilizumab (a humanized anti-CD3 monoclonal antibody) and to determine a maximum tolerated dose in patients with severe ulcerative colitis that had not responded to 5 days of treatment with intravenous corticosteroids.
In this open-label phase 1 study, 32 subjects received visilizumab at a dose of 10 or 15 microg/kg, administered intravenously on 2 consecutive days. Clinical response was defined as a Modified Truelove and Witts Severity Index <10 with a minimum decrease of 3 points; remission was <4 points. Endoscopic remission was a Mayo endoscopic subscore of 0 or 1.
Eight patients received 15 microg/kg visilizumab. Because of dose-limiting toxicities (T-cell recovery >30 days in 2 of 8 patients), the dose was reduced to 10 microg/kg in 24 patients. On day 30, 84% of patients demonstrated a clinical response, 41% achieved clinical remission, and 44% achieved endoscopic remission. Forty-five percent of patients did not require salvage therapies or colectomy during the first year postdose. Mild to moderate symptoms of cytokine release occurred in 100% and 83% of patients in the 15- and 10-microg/kg dose groups, respectively. All patients exhibited a rapid decrease in circulating CD4(+) T-cell counts, which returned to baseline values by day 30 in 26 of 30 evaluable patients (86%). There were no serious infections.
Visilizumab had an acceptable safety profile at the 10-microg/kg dose level and may be clinically beneficial in patients with severe intravenous corticosteroid-refractory ulcerative colitis.
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ABSTRACT: OKT3, a mouse monoclonal antibody (Ab) specific for the human CD3 complex on T cells, is a potent immunosuppressive agent used for the treatment of acute allograft rejection. The utility of the drug has been limited by a neutralizing anti-mouse Ab response and adverse side effects resulting from T cell activation and systemic cytokine release. T cell activation is caused by OKT3-mediated cross-linking of T cells and Fc receptor-bearing cells. Studies in the mouse model have shown that global T cell activation is not necessary for immunosuppression, as Fc receptor-nonbinding anti-CD3 Abs can suppress graft rejection in the absence of the activation effects seen with Fc receptor-binding Abs. Thus, a humanized anti-CD3 antibody with a low affinity for Fc receptors might improve immunosuppressive therapy by reducing the side effects associated with OKT3. We developed a mouse monoclonal Ab, M291, which competes with OKT3 for binding to T cells. Humanized, complementary-determining region-grafted versions of M291 featuring various Fc were engineered, including a previously described IgG2 mutant deficient in Fc receptor binding (HuM291). Compared with OKT3 and HuM291-IgG1, HuM291 was significantly less mitogenic to T cells in vitro and induced the release of much lower levels of the cytokines tumor necrosis factor-alpha, interferon-gamma, and interleukin-10. Despite this reduction in T cell activation, HuM291 retained the ability to modulate the CD3 complex and inhibit the mixed lymphocyte reaction. When evaluated in vivo, HuM291 may be an immunosuppressive agent associated with less of the acute toxicity and immunogenicity seen with OKT3 therapy.Transplantation 09/1999; 68(4):563-71. · 3.78 Impact Factor
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ABSTRACT: Infliximab, a chimeric monoclonal antibody directed against tumor necrosis factor alpha, is an established treatment for Crohn's disease but not ulcerative colitis. Two randomized, double-blind, placebo-controlled studies--the Active Ulcerative Colitis Trials 1 and 2 (ACT 1 and ACT 2, respectively)--evaluated the efficacy of infliximab for induction and maintenance therapy in adults with ulcerative colitis. In each study, 364 patients with moderate-to-severe active ulcerative colitis despite treatment with concurrent medications received placebo or infliximab (5 mg or 10 mg per kilogram of body weight) intravenously at weeks 0, 2, and 6 and then every eight weeks through week 46 (in ACT 1) or week 22 (in ACT 2). Patients were followed for 54 weeks in ACT 1 and 30 weeks in ACT 2. In ACT 1, 69 percent of patients who received 5 mg of infliximab and 61 percent of those who received 10 mg had a clinical response at week 8, as compared with 37 percent of those who received placebo (P<0.001 for both comparisons with placebo). A response was defined as a decrease in the Mayo score of at least 3 points and at least 30 percent, with an accompanying decrease in the subscore for rectal bleeding of at least 1 point or an absolute rectal-bleeding subscore of 0 or 1. In ACT 2, 64 percent of patients who received 5 mg of infliximab and 69 percent of those who received 10 mg had a clinical response at week 8, as compared with 29 percent of those who received placebo (P<0.001 for both comparisons with placebo). In both studies, patients who received infliximab were more likely to have a clinical response at week 30 (P< or =0.002 for all comparisons). In ACT 1, more patients who received 5 mg or 10 mg of infliximab had a clinical response at week 54 (45 percent and 44 percent, respectively) than did those who received placebo (20 percent, P<0.001 for both comparisons). Patients with moderate-to-severe active ulcerative colitis treated with infliximab at weeks 0, 2, and 6 and every eight weeks thereafter were more likely to have a clinical response at weeks 8, 30, and 54 than were those receiving placebo. (ClinicalTrials.gov numbers, NCT00036439 and NCT00096655.)New England Journal of Medicine 01/2006; 353(23):2462-76. · 51.66 Impact Factor
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ABSTRACT: Despite treatment with corticosteroids, severe to moderately severe attacks of ulcerative colitis have a high colectomy rate. We intended to find a rescue therapy other than cyclosporin A, which imposes a high risk of side effects and cyclosporine-related mortality. This was a randomized double-blind trial of infliximab or placebo in severe to moderately severe ulcerative colitis not responding to conventional treatment. Patients were randomized to infliximab/placebo either on day 4 after the initiation of corticosteroid treatment if they fulfilled the index criteria for fulminant ulcerative colitis on day 3 or on day 6-8 if they fulfilled index criteria on day 5-7 for a severe or moderately severe acute attack of ulcerative colitis. Results were analyzed according to the intention-to-treat principle. The primary end point was colectomy or death 3 months after randomization. Secondary end points were clinical and endoscopic remission at that time in patients who did not undergo operation. Forty-five patients were included (24 infliximab and 21 placebo). No patient died. Seven patients in the infliximab group and 14 in the placebo group had a colectomy (P = .017; odds ratio, 4.9; 95% confidence interval, 1.4-17) within 3 months after randomization. No serious side effects occurred. Three patients in the placebo group required operation for septic complications. Infliximab 4-5 mg/kg is an effective and safe rescue therapy in patients experiencing an acute severe or moderately severe attack of ulcerative colitis not responding to conventional treatment.Gastroenterology 07/2005; 128(7):1805-11. · 12.82 Impact Factor