Study design and participants
The study was a prospective, single center, observational study on F508del homozygous adults with CF who commenced treatment with LUM-IVA and were followed for one year. Pregnant or nursing women, solid organ or hematological transplant recipients, individuals with alcohol or substance abuse, patients with an acute upper or lower respiratory infection, and patients with PEx or changes in therapy within 28 days before Day 1 (first dose of LUM-IVA) were excluded.
All subjects received 400 mg Lumacaftor and 250 mg Ivacaftor (LUM-IVA) fixed-dose combination film coated tablets for oral administration every 12 h. All participants remained on their pre-study stable CF medication regimen throughout the year. They were followed in the CF Center at Carmel Medical Center, Haifa, Israel between November 2016 and June 2019. The institutional board reviewed and approved the study protocol, IRB number CMC108-16. All patients provided written informed consent prior to participation in the study. The ClinicalTrials.gov identifier of the study is NCT04623879.
In Israel, F508del allele frequency accounts for only around 23%, and therefore 13 adults with the F508del homozygous genotype attend our center.
The screening period started on Day − 28 and ended on Day − 1. The treatment period started on Day 1 and lasted 12 months (± 7 days), with clinic visits scheduled every three months (Day 1 and Weeks 12, 24, 36, and 48 ± 7 days).
The primary endpoint assessed pancreatic function via the absolute and relative change from baseline in oral glucose tolerance (OGTT) test through 12 months. Secondary endpoints included absolute and relative changes from baseline through 12 months in bone metabolism parameters, nutritional factors, reproductive hormones, sweat chloride, pulmonary status, and CF questionnaire-revised (CFQR) score.
Pancreatic function evaluation
At screening visit, 3 months, and 12 months, an OGTT was performed in patients without CF-related diabetes: 75 g of glucose were ingested, and glucose, insulin, and c-peptide were examined at three time points: 0, 1 h, and 2 h. In addition, HbA1C levels were evaluated in all patients at each study visit.
At screening and at 12 months, bone density was measured, using a dual-energy x-ray absorptiometry (DEXA) scan test. In addition, during every visit, bone metabolism factors, including parathyroid hormone (PTH), alkaline phosphatase, phosphorus, calcium, vitamin D levels (Vitamin D1-25-OH), and urine Ca/Cr ratio were assessed. All patients were treated with two DEKAs Plus soft gels every day (each soft gel containing 3000 IU vitamin D), as standard care in adult CF patients. Three patients received additional supplement of 2000 IU vitamin D every day, and one patient received 1000 IU every day. No patients received supplemental calcium.
Body mass index (BMI) and levels of vitamin A, E (absolute), and albumin were assessed at each visit.
Reproductive hormones including LH, FSH, testosterone, and estradiol were assessed at each visit in in both male and female participants.
Vital signs, physical examination, sputum cultures, laboratory tests (e.g. complete blood count [CBC] and chemistry tests including electrolytes, liver and kidney function, and coagulation function) were assessed at every visit.
Pulmonary and lung morphology evaluations were carried out by:
(1) The absolute change from baseline in the percentage of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and forced expiratory flow between 25–75 (FEF25-75), all were assessed at each visit. To obtain these parameters, spirometry was performed in accordance with the American Thoracic Society/European Respiratory Society (ATS/ERS) Task Force, using a KoKo® spirometer (n-Spire Healthcare, Inc., Longmont CO, USA) . Absolute values of spirometry were transferred to percent predicted (pp) using Global Lung Function Initiative (GLI) reference data. (2) Chest computed tomography (CT) scans were performed at baseline and after one year, scored using the Bhalla scoring method  by a radiologist-investigator (the total score ranges from 9 to 25, with a higher score indicating more severe structural lung changes). (3) Quality of life was measured using the Cystic Fibrosis Questionnaire-Revised (CFQ-R) respiratory domain score each visit (scores range from 0 to 100, with higher scores indicating a better quality of life and four points considered to be a minimal clinically important difference) . (4) PEx was defined as deteriorations in respiratory symptoms that led to changes in treatment . Each PEx was considered a separate event, and the number of PEx during one year prior to commencing treatment with LUM-IVA was compared to PEx through the first year of treatment. We documented the number of exacerbations, oral vs. intravenous (IV) antibiotic treatments, hospitalizations, presence of fever > 38 °C, laboratory parameters: white blood cells count [WBC], absolute neutrophil count [ANC], and C-reactive protein [CRP] at the initiation of PEx (in hospitalized patients), sputum culture results, and time to next PEx.
Evaluation was measured through testing the concentration of sweat chloride that was performed at screening and after one year of treatment by Macroduct ® sweat collection system .
Statistical analyses were performed using the SAS version 9.4 (SAS Institute, Cary North Carolina, USA). All measured variables and derived parameters were tabulated using descriptive statistics. For categorical variables, summary tables are provided presenting sample size and absolute and relative frequency. For continuous variables, summary tables are provided presenting sample size, arithmetic mean, standard deviation, median, minimum, and maximum for means of variables. Wilcoxon Signed-Rank test for paired samples was applied for testing the statistical significance of the changes from visits 3 and 12 to baseline in Table 2 and from visits 3, 6,9,12 to baseline in Tables 3 and 4, and Supplementary Table 1 and 2. A paired t-test for two means (repeated observations) was applied for testing the statistical significance of the change from baseline for each continuous variable. All tests were two-tailed, and a p-value of 5% or less was considered statistically significant.