Preliminary evidence from a large, randomized trial suggests that treatment with IFN-gamma 1b results in lower mortality in IPF patients. However, anecdotal reports have suggested that treatment may occasionally be associated with respiratory decompensation. Therefore, we evaluated SAEs reported in an open-label study of IFN-gamma 1b for IPF patients.
All patients who completed a randomized, double-blind, placebo-controlled Phase 3 study and were tolerant of IFN-gamma 1b were offered participation in this 48-week open-label study. During treatment with IFN-gamma 1b (200 mcg subcutaneously thrice weekly), SAEs were defined as those that were fatal, persistently or significantly disabling, resulted in or prolonged hospitalization, were congenital, or required medical or surgical intervention. Patients were categorized by treatment assignment in the Phase 3 study: those assigned to IFN-gamma 1b were considered “long-term” patients and those originally on placebo initiating IFN-gamma 1b in this study were considered “newly treated.”.
210 patients participated: 109 from the 162 patients assigned to IFN-gamma 1b in the Phase 3 study and 101 from the 168 patients assigned to placebo. As of April 21, 2004, SAEs occurred in 40 (37%) and 41 (41%) of long-term users and newly treated patients, respectively. At least one respiratory SAE occurred in 29% and 27% of the two groups, respectively, and the proportion who had a respiratory SAE and died at any time was similar in both groups (12% and 11%, respectively).
Rates of all SAEs and respiratory SAEs were similar in patients newly treated with IFN-gamma 1b and in patients undergoing long-term IFN-gamma 1b treatment. The proportion of patients with respiratory adverse events who died was similar in both groups.
Initial treatment with IFN-gamma 1b compared with long-term treatment does not appear to be associated with an increased rate of SAEs, respiratory SAEs, or death in those with respiratory SAEs.
D.A. Zisman, Funding provided by InterMune, Inc.