Safety and efficacy of intrathecal interferon-α therapy in subacute sclerosing panencephalitis - An interim analysis

Abstract

Definitive therapy for subacute sclerosing panencephalitis (SSPE) does not exist. In view of sparse availability of isoprinosine, and issues related with intraventricular instillation of intraventricular interferon-α2b (IFN), we planned to evaluate the safety and efficacy of intrathecal IFN (IT-IFN) in patients with SSPE. Patients diagnosed with SSPE, as per Dyken’s criteria, and enrolled between September 2015 and February 2017 at King George’s Medical University, Lucknow, India were analyzed. IT-IFN, 6 million units, was given weekly for 6 weeks and then monthly for 6 months; those with stage IV as per Jabbour’s classification were excluded. Clinical, electroencephalography, cerebrospinal fluid and imaging parameters were recorded at baseline and at the completion of study period (7½ months). Modified Ranking Scale (mRS), Barthel Index (BI) and Guy’s Neurological Disability Scale (GNDS) were used to assess disability. Those who refused IT-IFN, constituted the control group. Out of a total of 47 patients, 24 patients who received IT-IFN, 6 (25%) patients showed improvement in their Jabbour’s stage while only 1 (4.3%) patient in the control group showed improvement. Three (12.5%) patients in the IT-IFN group and 12 (52.2%) in the control group progressed to next higher stage (p=0.007). A non-significant improvement in mRS and a significant improvement in BI and GNDS scores was observed in those receiving IT-IFN. Besides transient flu-like symptoms no other adverse events were observed. IT-IFN regime appears to be well-tolerated and effective in SSPE. Further comparison with isoprinosine should be done to compare their combined efficacy.