Background
Phase III, randomized, double-blind, placebo-controlled RCT. 128 patients with chronic granulomatous disease (CGD), a primary immunodeficiency caused by defective NADPH oxidase leading to inability of phagocytes to generate reactive oxygen intermediates. Patients experienced recurrent severe bacterial and fungal infections. Median age 15 years (range included children and adults). Both X-linked and autosomal recessive forms included. Prophylactic antibiotics permitted in both arms.
Interventions and follow up
Arm A: Interferon-gamma (IFN-γ) 50 μg/m² SC three times weekly for up to 12 month
Arm B: Placebo SC three times weekly
Primary endpoint: Time to first serious infection (requiring hospitalization and parenteral antibiotics)
mFollow up: 12 month
Arm B: Placebo SC three times weekly
Primary endpoint: Time to first serious infection (requiring hospitalization and parenteral antibiotics)
mFollow up: 12 month
Results
Time to first serious infection: Significant benefit for IFN-γ vs placebo, P=.0006
Patients with serious infections: 14/63 (22%) vs 30/65 (46%), P=.002
Total serious infections: 20 vs 56, P<.0001
Antibiotic use duration: ~70% reduction with IFN-γ
Patients with serious infections: 14/63 (22%) vs 30/65 (46%), P=.002
Total serious infections: 20 vs 56, P<.0001
Antibiotic use duration: ~70% reduction with IFN-γ
Adverse events
Main adverse events: IFN-γ generally well-tolerated. Flu-like symptoms (fever, chills, headache) common but manageable with acetaminophen. No serious drug-related adverse events. No increase in autoimmune events. No evidence of stimulation of NADPH oxidase activity by superoxide assays (mechanism of benefit uncertain).
Conclusions
Interferon-gamma 50 μg/m² SC three times weekly significantly reduced the frequency, number, and duration of serious infections in patients with CGD, regardless of age, antibiotic prophylaxis status, or mode of inheritance. This trial established IFN-γ as standard prophylaxis for CGD.
Key Limitations
Key Limitations: The mechanism by which IFN-γ reduces infections in CGD remains unclear — no significant restoration of NADPH oxidase activity was observed, suggesting non-oxidative mechanisms (enhanced phagocytosis, cytokine activation). Relatively small trial (N=128) conducted in patients with heterogeneous disease severity. The benefit may be less pronounced in the era of aggressive triazole antifungal prophylaxis, which was not standard in 1991. Long-term MDS/leukemia risk in CGD is not addressed by this trial.
Clinical Context
IFN-γ (Actimmune) received FDA approval for CGD prophylaxis in 1990 and remains the standard of care. Current practice combines TMP-SMX, itraconazole/voriconazole, AND IFN-γ for CGD prophylaxis. Definitive cure is allogeneic HSCT, which is increasingly offered due to favorable outcomes in matched sibling and unrelated donor settings. Gene therapy approaches are in development. This trial is the founding evidence for IFN-γ in CGD.
References