Treatment of primary Sjögren's syndrome with low-dose human interferon alfa administered by the oromucosal route: combined phase III results.

Objective: This study tested the safety and efficacy of human interferon (IFN) alfa for treatment of salivary hypofunction and dry mouth symptoms in primary Sjögren's syndrome patients.

Methods: Combined results are reported from 2 phase III clinical trials in which a total of 497 subjects with primary Sjögren's syndrome received 150 international units of human IFN alfa or matching placebo 3 times per day for 24 weeks by the oromucosal route.

Results: Subjects given IFN alfa had a significantly (P = 0.01) greater mean increase in unstimulated whole saliva (UWS) flow, compared with subjects given placebo. In IFN alfa patients, increases in UWS correlated positively and significantly with improvements noted in 7 of 8 symptoms associated with oral and ocular dryness. The coprimary endpoints of stimulated whole saliva flow and oral dryness were not significantly improved in the IFN alfa group relative to placebo. No significant differences were found between the groups with respect to overall adverse event incidence or severity.

Conclusion: IFN alfa given at low dosage by the oromucosal route can significantly increase UWS flow in patients with primary Sjögren's syndrome, without causing significant adverse events.