Natalizumab for moderate to severe Crohn's disease in clinical practice: The Mayo Clinic Rochester experience

Background: Not all patients with Crohn's disease (CD) respond or maintain response to anti-tumor necrosis factor (TNF) agents and alternative treatment is necessary. Natalizumab, a monoclonal antibody to alpha-4 integrin approved for CD, has demonstrated efficacy in randomized clinical trials. We describe our experience with natalizumab in clinical practice at Mayo Clinic Rochester. Methods: Consecutive patients prescribed natalizumab for active CD were invited to participate and were followed prospectively. Incidence of infection, hospitalization, neoplasm, or other adverse events were recorded. Clinical activity was assessed using the Harvey-Bradshaw Index at each 30-day infusion visit. Results: Between April 2008 and September 2010, 36 patients were prescribed natalizumab and 30 (83.3%) agreed to participate. Median disease duration was 9 years (range, 3-43). Twenty-three patients had prior exposure to two anti-TNF agents, seven to one agent. All patients experienced at least one adverse event; none of the 13 patients in whom natalizumab was stopped (43%) discontinued due to adverse events. Five patients had infusions held for infection. No patient developed progressive multifocal leukoencephalopathy (PML). Fourteen patients (46%) had clinical response. The cumulative probability of achieving complete response within 1 year was 56% (28%-73%). Four of seven patients were weaned off corticosteroids. Conclusions: In our experience with natalizumab in clinical practice, adverse events were manageable and did not result in treatment cessation. No PML cases were seen and clinical response was similar to that in clinical trials. Natalizumab results in clinical benefit in patients who have active disease and have failed anti-TNF therapy.