The risk of malignancy is not increased in patients with multiple sclerosis treated with subcutaneous interferon beta-1a: analysis of data from clinical trial and post-marketing surveillance settings

Abstract

Background: Risks that are potentially associated with long-term therapies should be assessed. Objective: The present analyses were performed to determine the risk of malignancy in patients with multiple sclerosis (MS) receiving subcutaneous (sc) interferon (IFN) beta-1a, using pooled safety data from key clinical trials and data from the Merck Serono Global Drug Safety database. Methods: The standard Medical Dictionary for Regulatory Activities query “malignancies” was used to retrieve relevant cases from each data set. The incidence of malignancies per 1000 patient-years was calculated using the pooled safety data from clinical trials. The reporting rates of malignancy types were calculated for the post-marketing setting based on sales volume. Malignancies were grouped by organ localization and classified as medically confirmed or not medically confirmed according to the source of each report. The number of reported cases of each type was compared with the expected number in the general population. Results: Analysis of pooled safety data from 12 key clinical trials did not show an increased incidence of malignancy per 1000 patient-years with sc IFN beta-1a (4.0; 95% confidence interval (CI): 2.9–5.5) compared with placebo (6.4; 95% CI: 3.3–11.2). Analysis of the database shows that among the medically confirmed cases, reported to expected ratios ranged from 1 : 6 to 1 : 18 for solid tumours and from 1 : 2 to 1 : 9 for lymphohaematopoietic tumours. Conclusion: Safety data from both clinical trial and post-marketing settings suggest that treatment with sc IFN beta-1a does not increase the risk of malignancy in patients with MS.