Impact of day-to-day variation in FEV1 on measures of change: A conceptual description.

Clinical trials often demonstrate treatment efficacy through change in forced expiratory volume in one second (FEV1), comparing single FEV1 measurements from post- versus pre-treatment timepoints. Day-to-day variation in measured FEV1 is common for reasons such as diurnal variation and intermittent health changes, relative to a stable, monthly average. This variation can alter estimation of associations between change in FEV1 and baseline in predictable ways, through a phenomenon called regression to the mean. We quantify and explain day-to-day variation in percent-predicted FEV1 (ppFEV1) from 4 previous trials, and we present a statistical, data-driven explanation for potential bias in ceiling and floor effects due to commonly observed amounts of variation. We recommend accounting for variation when assessing associations between baseline value and change in CF outcomes in single-arm trials, and we consider possible impact of variation on conventional standards for study eligibility.

Treatment of small as well as large declines in lung function enhances recovery to baseline in people with CF.

BACKGROUND: The benefit of antibiotic treatment of acute drops in FEV1 percent predicted (FEV1pp) has been clearly established, but data from the early 2000s showed inconsistent treatment. Further, there is no empirical evidence for what magnitude of drop is clinically significant. METHODS: We used data from the CF Foundation Patient Registry (CFFPR) from 2016 to 2019 to determine the association between treatment (any IV antibiotics, only oral or newly prescribed inhaled antibiotics, or no antibiotic therapy) following a decline of ≥5% from baseline FEV1pp and return to 100% baseline FEV1pp days using multivariable logistic regression including an interaction between the magnitude of decline and treatment category. RESULTS: Overall, 16,495 PWCF had a decline: 16.5% were treated with IV antibiotics, 25.0% non-IV antibiotics, and 58.5% received no antibiotics. Antibiotic treatment was more likely for those with lower lung function, history of a positive PA culture, older age and larger FEV1 decline (p < 0.001). Treatment with IV antibiotics or oral/inhaled antibiotics was associated with a higher odds of recovery to baseline compared to no treatment across all levels of decline, including declines of 5%-10%. CONCLUSIONS: A large proportion of acute drops in FEV1pp continue to be untreated, especially in younger patients and those with higher baseline lung function. Acute drops as small as 5% predicted are less likely to be recovered if antibiotic treatment is not prescribed. These findings suggest the need for more aggressive antimicrobial treatment of acute drops in FEV1, including those of a magnitude previously believed to be associated with self-recovery.

Characteristics of individuals with cystic fibrosis in the United States ineligible for ivacaftor and elexacaftor/tezacaftor/ivacaftor.

BACKGROUND: We characterized people with cystic fibrosis (CF) ineligible by genotype (not age) for currently approved CFTR modulator therapy using data from the US CF Foundation Patient Registry (CFFPR). METHODS: We summarized clinical characteristics using CFFPR data from 2017 to 2022. Annual rate of change in percent predicted of forced expiratory volume in one second (ppFEV1) was estimated using generalized estimating equations. RESULTS: A total of 2,790 individuals with CF met inclusion criteria. In 2022, 12 % were less than 6 years old, 16 % were age 6-12 years, 18 % age 12-18 years and 54 % were ≥18 years. The proportion identified as White was 74 %, 17 % Black, and 26 % as Hispanic. The median (IQR) age at diagnosis was 1.2 (0.5, 9.1) months for children and 3.1 (0.3, 17.4) years for adults. Median (IQR) ppFEV1 among children was 91.9 (80.3; 102.4) and among adults, 74.3 (52.4; 90.4). Pancreatic enzymes were prescribed for 77.8 %. Population-level average (95 % CI) rates of decline in ppFEV1 among the pancreatic insufficient population was -1.5 per year (-1.8; -1.2) for ages 6 to <11 years, -2.2 per year (-2.6; -1.8) for ages 12 to <18 years, and -1.5 per year (-1.7; -1.3) for adults. CONCLUSIONS: We describe the CFTR modulator ineligible population in the US in 2017-2022. With a growing pipeline of therapies aimed at improving CFTR function for those who cannot benefit from modulators due to ineligibility, characterization of both the size and outcomes of these populations are critical to inform optimal clinical development plans and future clinical trials.

FEV1 Variability Predicts Lung Transplant or Mortality in Cystic Fibrosis Patients in the US.

RATIONALE: Declines in percent predicted Forced Expiratory Volume in 1 Second (ppFEV1) are an important marker of clinical progression of Cystic Fibrosis (CF). OBJECTIVES: We examined ppFEV1 variability on a combined outcome of lung transplant or death. METHODS: We estimated the association between ppFEV1 variability and the combined outcome of lung transplant or death. We included children ages 8 years and above with CF and two prior years of ppFEV1 data before baseline between 2005 and 2021. We defined ppFEV1 increased variability as any relative increase or decrease of at least 10% in ppFEV1 from a two-year averaged baseline. A marginal structural Cox proportional hazards model was used. We examined a cumulative measure of ppFEV1 variability, defined as the cumulative proportion of visits with ppFEV1 variability at each visit. Kaplan-Meier survival curves were generated based upon quartiles of the cumulative distribution of ppFEV1 variability. MEASUREMENTS AND MAIN RESULTS: We included 9,706 CF patients in our cohort. Median age at cohort entry was 8.3 (IQR 8.2 - 8.4) years, 50% of patients were female, 94% white, and median baseline ppFEV1 was 94.4 (IQR 81.6 - 106.1). The unadjusted HR for increased ppFEV1 variability on lung transplant/mortality was 4.13 (95% CI 3.48 - 4.90) and the weighted HR was 1.49 (95% CI 1.19 - 1.86). Survival curves stratified by quartile of cumulative variability demonstrated an increased hazard of lung transplant/mortality as the proportion of cumulative ppFEV1 variability increased. CONCLUSIONS: We found a strong association between ppFEV1 variability and lung transplant or mortality in a cohort of people with CF in the US.

The impact of switching to race-neutral reference equations on FEV1 percent predicted among people with cystic fibrosis.

RATIONALE: The American Thoracic Society recommended switching to race-neutral spirometry reference equations, as race is a social construct and to avoid normalizing disparities in lung function due to structural racism. Understanding the impact of the race-neutral equations on percent predicted forced expiratory volume in one second (ppFEV1) in people with cystic fibrosis (PwCF) will help prepare patients and providers to interpret pulmonary function test results. OBJECTIVE(S): To quantify the impact of switching from Global Lung Initiative (GLI) 2012 race-specific to GLI 2022 Global race-neutral reference equations on the distribution of ppFEV1 among PwCF of different races. METHODS: Cross-sectional analysis of FEV1 among PwCF ages ≥6 years in the 2021 U.S. Cystic Fibrosis Foundation Patient Registry. We describe the absolute difference in ppFEV1 between the two reference equations by reported race and the effect of age and height on this difference. RESULTS: With the switch to GLI Global, ppFEV1 will increase for White (median increase 4.7, (IQR: 3.1; 6.4)) and Asian (2.6 (IQR: 1.6; 3.7)) individuals and decrease for Black individuals (-7.7, (IQR: -10.9; -5.2)). Other race categories will see minimal changes in median ppFEV1. Individuals with higher baseline ppFEV1 and younger age will see a greater change in ppFEV1 (i.e., a greater improvement among White and Asian individuals and a greater decline among Black individuals). CONCLUSIONS: Switching from GLI 2012 race-specific reference equations to GLI 2022 Global race-neutral equations will result in larger reductions in ppFEV1 among Black individuals with CF than increases among White and Asian people with CF.

Clinical outcomes at 9-10 years of age in children born with cystic fibrosis transmembrane conductance regulator related metabolic syndrome.

BACKGROUND AND OBJECTIVES: There are limited data on cystic fibrosis (CF) transmembrane conductance regulator-related metabolic syndrome (CRMS) outcomes beyond infancy. The goal of this study was to analyze outcomes of infants with CRMS up to the age of 9-10 years using the CF Foundation Patient Registry (CFFPR). METHODS: We analyzed data from the CFFPR for individuals with CF and CRMS born between 2010 and 2020. We classified all patients based on the clinical diagnosis reported by the CF care center and the diagnosis using CFF guideline definitions for CF and CRMS, classifying children into groups based on agreement between clinical report and guideline criteria. Descriptive statistics for the cohort were calculated for demographics, nutritional outcomes, and microbiology for the first year of life and lung function and growth outcomes were summarized for ages 6-10 years. RESULTS: From 2010 to 2020, there were 8765 children with diagnosis of CF or CRMS entered into the CFFPR with sufficient diagnostic data for classification, of which 7591 children had a clinical diagnosis of CF and 1174 had a clinical diagnosis of CRMS. CRMS patients exhibited normal nutritional indices and pulmonary function up to age 9-10 years. The presence of respiratory bacteria associated with CF, such as Pseudomonas aeruginosa from CRMS patients ranged from 2.1% to 9.1% after the first year of life. CONCLUSIONS: Children with CRMS demonstrate normal pulmonary and nutritional outcomes into school age. However, a small percentage of children continue to culture CF-associated respiratory pathogens after infancy.

Enhancing immunogenic responses through CDK4/6 and HIF2α inhibition in Merkel cell carcinoma.

Approximately 50% of Merkel cell carcinoma (MCC) patients facing this highly aggressive skin cancer initially respond positively to PD-1-based immunotherapy. Nevertheless, the recurrence of MCC post-immunotherapy emphasizes the pressing need for more effective treatments. Recent research has highlighted Cyclin-dependent kinases 4 and 6 (CDK4/6) as pivotal cell cycle regulators gaining prominence in cancer studies. This study reveals that the CDK4/6 inhibitor, palbociclib can enhance PD-L1 gene transcription and surface expression in MCC cells by activating HIF2α. Inhibiting HIF2α with TC-S7009 effectively counteracts palbociclib-induced PD-L1 transcription and significantly intensifies cell death in MCC. Simultaneously, co-targeting CDK4/6 and HIF2α boosts ROS levels while suppressing SLC7A11, a key regulator of cellular redox balance, promoting ferroptosis- a form of immunogenic cell death linked to iron. Considering the rising importance of immunogenic cell death in immunotherapy, this strategy holds promise for improving future MCC treatments, markedly increasing immunogenic cell death various across various MCC cell lines, thus advancing cancer immunotherapy.