Abstract: Six studies were eligible for inclusion (517 patients). Five studies compared type I IFNs to placebo injections (485 patients) and a single study compared IFNs to prednisolone enemas in patients with left-sided colitis (32 patients). The active comparator study was rated as high risk of bias due to an open-label design. Three studies were rated as unclear risk of bias for random sequence generation and allocation concealment. Two studies described as double blind were rated as unclear risk of bias for blinding. There was no significant benefit of type I IFNs over placebo for inducing clinical remission or improvement in patients with active ulcerative colitis. Thirty-six per cent (87/242) of patients in the type I IFNs group achieved clinical remission by 8 to 12 weeks compared to 30% (36/120) of placebo patients (RR 1.16, 95% CI 0.84 to 1.58; 4 studies, 362 patients). A GRADE analysis indicated that the overall quality of the evidence supporting the outcome clinical remission was moderate due to sparse data (123 events). Fifty-six per cent (149/264) of patients in the type I IFNs group improved clinically by 8 to 12 weeks compared to 48% (77/161) of placebo patients (RR 1.16, 95% CI 0.96 to 1.40; 4 studies, 425 patients). A GRADE analysis indicated that the overall quality of the evidence supporting the outcome clinical improvement was moderate due to sparse data (226 events). Patients who received type I IFNs were significantly more likely to withdraw from the studies due to adverse events than those who received placebo. Seven per cent (18/42) of type I IFNs patients withdrew due to adverse events compared to 2% (3/152) of placebo patients (RR 3.16, 95% CI 1.06 to 9.40). A GRADE analysis indicated that the overall quality of the evidence supporting the outcome withdrawal due to adverse events was low due to very sparse data (21 events). The study comparing type I IFNs to prednisolone enemas found no difference between the treatment groups in quality of life or disease activity scores. Common adverse events included headaches, arthralgias, myalgias, fatigue, back pain, nausea, application site reactions, rigors, and fevers. There were no statistically significant differences in the other secondary outcomes. Moderate quality evidence suggests that type I IFNs are not effective for the induction of remission in UC. In addition, there are concerns regarding the tolerability of this class of treatment.

Plain-language summary: The researchers identified six studies that included a total of 517 participants. Five studies (total 485 participants) compared type I IFNs to placebo (fake medicine) injections. One small (32 participants) low quality study compared types I IFNs to prednisolone (a steroid drug) enemas. This study did not measure remission and found no difference between the treatment groups in quality of life or disease activity scores. There was no difference between type I interferons and placebo treatment groups for the number of people who achieved remission or improvement of their symptoms. These results suggest that type I IFNs do not produce remission from ulcerative colitis. Common side effects included headaches, arthralgias (joint pain), myalgias (muscle pain), fatigue, back pain, nausea, injection site reactions, rigors (cold and shivering), and fevers. At present, the results from medical trials do not support the use of type I IFNs for the production of remission in active ulcerative colitis.