WS05.4 Clinical effectiveness results from the first interim analysis of the VOCAL study; an observational study of ivacaftor in patients with cystic fibrosis and selected non-G551D gating mutations

Long-Term Impact of Ivacaftor on Healthcare Resource Utilization Among People with Cystic Fibrosis in the United States

INTRODUCTION

Ivacaftor was first approved in 2012 for the treatment of a select population of individuals with cystic fibrosis (CF), a rare, life-shortening genetic disease. Reductions in healthcare resource utilization (HCRU) associated with ivacaftor have been observed during limited follow-up and for selected outcomes in real-world studies. This study aimed to further describe the long-term impact of ivacaftor treatment on multiple measures of HCRU among people with CF (pwCF).

METHODS

This retrospective study used US commercial and Medicaid claims data from 2011-2018. We included pwCF ≥ 6 years of age with ≥ 1 claim for ivacaftor and 12 months of continuous health plan enrollment before ivacaftor initiation ("pre-ivacaftor" period) who also had 36 months of continuous enrollment and persistent ivacaftor use (i.e., no gap ≥ 90 days between refills) following initiation ("post-ivacaftor" period). We compared comorbidities occurring pre-ivacaftor versus the last 12 months post-ivacaftor. HCRU outcomes included medication use, inpatient admissions, and outpatient office visits. We compared medication use pre-ivacaftor versus the last 12 months post-ivacaftor and inpatient admissions and outpatient office visits pre-ivacaftor versus the post-ivacaftor period annualized across 36 months.

RESULTS

Seventy-nine pwCF met all criteria, including persistent ivacaftor use during the post-ivacaftor period. Ivacaftor treatment was associated with a significant reduction in pneumonia prevalence (10.1% vs. 26.6%; p < 0.001) and significantly fewer mean [SD] antibiotics claims (8.0 [7.3] vs. 12.3 [11.1]; p < 0.001) in the last 12 months post-ivacaftor versus pre-ivacaftor. In comparing the 36-month post-ivacaftor period to the pre-ivacaftor period, we also observed fewer mean [SD] annual inpatient admissions (0.2 [0.4] vs. 0.4 [0.7]), CF-related inpatient admissions (0.1 [0.2] vs. 0.2 [0.5]), and outpatient office visits (8.8 [4.9] vs. 9.9 [5.4]) (all, p < 0.05).

CONCLUSION

Long-term ivacaftor treatment reduced HCRU, consistent with trends observed in prior real-world studies. Our results support the sustained, long-term value of ivacaftor treatment in reducing CF burden.

Real-World Outcomes of Ivacaftor Treatment in People with Cystic Fibrosis: A Systematic Review

Cystic fibrosis (CF) is a rare, progressive, multi-organ genetic disease. Ivacaftor, a small-molecule CF transmembrane conductance regulator modulator, was the first medication to treat the underlying cause of CF. Since its approval, real-world clinical experience on the use of ivacaftor has been documented in large registries and smaller studies. Here, we systematically review data from real-world observational studies of ivacaftor treatment in people with CF (pwCF). Searches of MEDLINE and Embase identified 368 publications reporting real-world studies that enrolled six or more pwCF treated with ivacaftor published between January 2012 and September 2019. Overall, 75 publications providing data from 57 unique studies met inclusion criteria and were reviewed. Studies reporting within-group change for pwCF treated with ivacaftor consistently showed improvements in lung function, nutritional parameters, and patient-reported respiratory and sino-nasal symptoms. Benefits were evident as early as 1 month following ivacaftor initiation and were sustained over long-term follow-up. Decreases in pulmonary exacerbations, Pseudomonas aeruginosa prevalence, and healthcare resource utilization also were reported for up to 66 months following ivacaftor initiation. In studies comparing ivacaftor treatment to modulator untreated comparator groups, clinical benefits similarly were reported as were decreases in mortality, organ-transplantation, and CF-related complications. The safety profile of ivacaftor observed in these real-world studies was consistent with the well-established safety profile based on clinical trial data. Our systematic review of real-world studies shows ivacaftor treatment in pwCF results in highly consistent and sustained clinical benefit in both pulmonary and non-pulmonary outcomes across various geographies, study designs, patient characteristics, and follow-up durations, confirming and expanding upon evidence from clinical trials.

Effectivenesss of ivacaftor in severe cystic fibrosis patients and non-G551D gating mutations

BACKGROUND

Ivacaftor is a significant innovation in the treatment of cystic fibrosis (CF) with gating mutations. A substantial percentage of patients with CF have severe lung involvement, but these patients are usually excluded from phase III clinical trials. Thus, the effectiveness of ivacaftor in this population has not been fully determined.

METHODS

Data were collected from Italian CF centers with patients enrolled in an ivacaftor compassionate use programme (percent predicted [pp] forced expiratory volume in 1 second [FEV₁ ] < 40%, or on lung transplant waiting list, or with a fast worsening trend of lung function). Data were collected for 1 year before and 1 year after ivacaftor commencement.

RESULTS

Thirteen patients received ivacaftor for a median of 320 days. Mean (SD) ppFEV₁ increased from 35.1% (14.3%) before treatment to 46.6% (18.8%) after 12 months of treatment (absolute increase 11.5%, relative increase 32.8%). Mean distance of the 6-minute walking test improved significantly, from 535.1 m before to 611.6 m after 12 months of treatment (P = .002). The number of pulmonary exacerbations decreased significantly, from 57 during the year before ivacaftor to 28 in the year following ivacaftor (P = .0048). Five of the 13 patients (38.5%) had no exacerbations during the 12 months after starting ivacaftor. Median weight increased significantly, from 52.7 kg to 55.6 kg (P = .0031). Mean (SD) sweat chloride concentration decreased significantly, from 99.5 (22.8) mmol/L to 39.3 (15.8) mmol/L (P < .0001). No safety concerns were registered.

CONCLUSIONS

Ivacaftor was safe and effective in patients with CF with severe lung disease and non-G551D gating mutations.