Sargramostim (GM-CSF) for induction of remission in Crohn's disease.

BACKGROUND

Crohn's disease is an inflammatory condition of the gut, thought to involve an overactive immune response to gut flora. A novel theory postulates possible immunodeficiency as a cause, and aims to use sargramostim (granulocyte macrophage colony stimulating factor, GM-CSF) to boost the immune system in an effort to test this hypothesis.

OBJECTIVES

The primary objectives were to determine the efficacy and safety of sargramostim for induction of remission in patients with clinically active Crohn's disease.

SEARCH METHODS

A systematic search of MEDLINE, EMBASE, and CENTRAL was conducted from inception to April 2011. Reference lists of relevant review articles were also searched. Trial registries and abstract databases including Digestive Diseases Week (1980-2010) and United European Gastroenterology Week (2005-2009) were searched to identify studies published in abstract form.

SELECTION CRITERIA

Randomized controlled trials of sargramostim for the treatment of patients with active Crohn's disease were considered for inclusion.

DATA COLLECTION AND ANALYSIS

Data from selected articles were extracted and the Cochrane Risk of Bias tool applied independently by two authors. The primary outcome was induction of clinical remission as defined by a Crohn's Disease Activity Index (CDAI) of < 150 at the end of treatment. Secondary outcomes included clinical responses measures on the CDAI and safety outcomes. Pooled risk ratios (RR) and 95% confidence intervals (CI) were calculated for dichotomous outcomes, in most cases using a random effects model due to high heterogeneity.

MAIN RESULTS

Three studies were identified, 2 published as full papers and one in abstract form (537 patients). The risk of bias was low for the 3 included studies. There was no statistically significant difference in the proportion of patients (GM-CSF 25.3% versus placebo 17.5%) who achieved clinical remission (RR 1.67; 95% CI 0.80 to 3.50; P = 0.17; 3 studies; 537 patients). There was no statistically significant difference in the proportion of patients (GM-CSF 38.3% versus placebo 24.8%) who achieved a 100-point clinical response (RR 1.71 95% CI 0.98 to 2.97; P = 0.06; 3 studies; 537 patients). There was no statistically significant difference in the proportion of patients (GM-CSF 54.3% versus placebo 44.2%) who achieved a 70 point clinical response (RR 1.23; 95% CI 0.83 to 1.82; P = 0.30; 1 study; 124 patients). There was no statistically significant difference in the proportion of patients (GM-CSF 95.8% versus placebo 89.3%) who experienced at least one adverse event (RR 1.07; 95% CI 0.99 to 1.16; P = 0.08; 2 studies; 251 patients), or serious adverse events (GM-CSF 12.0% versus placebo 4.8%; RR 2.21; 95% CI 0.84 to 5.81; P = 0.11; 2 studies; 251 patients). The incidence of bone pain, musculoskeletal chest pain, and dyspnea were higher in patients treated with sargramostim compared to placebo. Other adverse events commonly associated with sargramostim such as pulmonary capillary leak syndrome, pulmonary edema, heart failure, fever, and neurotoxicity were not reported in these studies.

AUTHORS' CONCLUSIONS: Sargramostim does not appear to be more effective than placebo for induction of clinical remission or clinical improvement in patients with active Crohn's disease. However, the GRADE analysis indicates that the overall quality of the evidence for the primary (clinical remission) and secondary outcomes (clinical response) was low indicating that further research is likely to have an impact on the effect estimates.