Safety and efficacy of intravenous cyclophosphamide pulse therapy in therapy refractory Crohn's disease patients

A major challenge in the management of persistently active Crohn's disease patient's refractory to treatment regimen following the current guidelines is the induction of remission, which is a prerequisite for subsequent maintenance therapy. The aim of this study was to evaluate both the clinical and endoscopic benefit of intravenous cyclophosphamide pulse therapy in patients with active and therapy refractory Crohn's disease. Nine patients with acute moderate to severe Crohn's disease, not responding to conventional as well as biological therapy regimen received 3 - 9 cycles of monthly treatments with intravenous cyclophosphamide (680 - 1000 mg) in an uncontrolled setting and were retrospectively analyzed. Eight of nine patients (88.9%) had a clinical response (measured by a decrease in the Harvey-Bradshaw index, HBI ≥ 3) and two of nine patients (22.2%) achieved clinical remission (HBI ≤ 4) at week 8 after two applications of intravenous cyclophosphamide therapy. These response and remission rates remained unchanged after individual completion of cyclophosphamide therapy. Median HBI decreased from 18 (7 - 25) at the beginning of therapy to 7 (3 - 18) at week 8. 5 of 9 patients (56%) showed endoscopic response (defined by a reduction of ulcers) and one patient (11%) reached endoscopic remission (defined by the absence of ulcers) after the last application of cyclophosphamide. Arthralgia, which was present in 4 of 9 (44%) patients, was unchanged in most patients after cyclophosphamide therapy, although one patient described a marked reduction in joint pain. Cyclophosphamide pulse therapy was well tolerated during the whole treatment course in all subjects. One patient with long-standing Crohn's disease was diagnosed with a high-grade intraepithelial neoplasia in the rectum and underwent surgical intervention, where the diagnosis of an early stage adenocarcinoma was made. We concluded that intravenous cyclophosphamide pulse therapy was well tolerated by most patients and effective for inducing clinical and endoscopic response and remission in patients with therapy refractory Crohn's disease. In patients who are unresponsive to available therapies, including available biological treatment options, cyclophosphamide therefore represents a potential option to induce therapeutic response, which must then be maintained by other treatment modalities.