The NATRON clinical trial was a 24-week, randomized, double-blind, placebo-controlled, Phase 3 study comparing the efficacy and safety of FASENRA to placebo in patients aged 12 years and older who had signs or symptoms of HES flare or had experienced at least 2 HES flares within the past 12 months.1,2 See the full study design.

Secondary endpoint: Change in fatigue-related symptoms and impacts from baseline to Week 24 (PROMIS Short Form 7a)1,2

LS mean change difference from baseline at Week 24: -4.72 (95% CI: -7.64 to -1.80; P=0.0017)*

Line Chart Showing Greater Reduction In PROMIS Fatigue Scores with Fasenra Vs Placebo Over 24 Weeks In Patient With HES Line Chart Showing Greater Reduction In PROMIS Fatigue Scores with Fasenra Vs Placebo Over 24 Weeks In Patient With HES

MCID for PROMIS Fatigue in this setting is not defined. Reported values reflect statistical differences only.

~2X greater reduction in fatigue with FASENRA compared to placebo*

Fatigue was measured by a change in the PROMIS Fatigue short-form 7A standardized T-score, which can range from 29.4 (lowest level of fatigue) to 83.2 (highest level of fatigue). A decrease in PROMIS Fatigue score indicates improvement in fatigue.

*LS mean change from baseline in PROMIS Fatigue score at Week 24: FASENRA -8.6 (95% CI: -10.6, -6.6) vs placebo -3.9 (95% CI: -6.0, -1.8).2

CI, confidence interval; LS, least squares; MCID, minimal clinically important difference; PROMIS, patient-reported outcomes measurement information system.