Adherence to cystic fibrosis transmembrane conductance regulator (CFTR) modulators: analysis of a national specialty pharmacy database

Assessment of long-term medication adherence with cystic fibrosis: An integrated approach

INTRODUCTION

Cystic fibrosis (CF) is a genetic disorder that creates a multisystem pathology resulting in complex treatment regimens. In 2014, 43% of people with CF at an academic medical center experienced medication acquisition barriers. The creation of an integrated specialty pharmacy with an embedded CF team pharmacist was launched in 2016. In addition to filling specialty medications, this specialty pharmacy filled all patient medications through a service called total care pharmacy (TCP). This service was hypothesized to positively impact medication adherence.

METHODS

Adherence analysis was performed by utilizing the proportion of days covered (PDC). PDC was analyzed during years 1, 2, and 3 of therapy. PDC was calculated for medications with at least three fills during each year. Patients with PDC less than 80% were considered nonadherent and underwent manual chart review to identify a documented reason for nonadherence.

RESULTS

Patients in the first year of dornase alfa therapy had significantly higher adherence in the TCP cohort compared to non-TCP (81.3% PDC vs. 66.0%; p = .006), which was largely driven by adult patients (73.3% vs. 56.5% for pediatric). Analysis of other medications and groups did not yield statistically significant differences. Many patients who had been classified as nonadherent had valid clinical reasons that explained gaps in therapy.

CONCLUSIONS

When filling medications at a specialty pharmacy integrated within the academic medication center, dornase alfa adherence was higher in the TCP group. Further studies comparing TCP with services offered by pharmacies external to the health system would better characterize the impact of TCP services.

Optimizing CFTR modulator therapy management for cystic fibrosis through the ReX platform

Background

Cystic fibrosis (CF) is a chronic multi-systemic disease that requires a complex daily treatment regimen. Therefore, there is sub-optimal adherence to CF therapies, and it was shown to impact its clinical and economic burden. Cystic fibrosis transmembrane conductance regulator modulators (CFTRm) are high-cost medications that demonstrated significant benefit in clinical trials. The aim of this study was to evaluate the safety, usability, and efficacy of the ReX platform in medication management of CFTRm for the treatment of people with CF (pwCF).

Methods

ReX is a patient engagement platform consisting of a cloud-based management system and a cell-enabled handheld device intended to dispense oral medication into the patient's mouth, following a pre-programmed treatment protocol. It provides real-time adherence data to caregivers and timely, personalized reminders to patients. This is a prospective multi-center open study for pwCFs older than 12 years, who had been prescribed CFTRm [elexacaftor/tezacaftor/ivacaftor (ETI) or tezacaftor/ivacaftor (TI)], and provided consent to use ReX platform to receive CFTRm and record their health condition. Study duration was 12-24 months, with clinic visits where physical examination, body mass index (BMI), and pulmonary function tests were performed, and user experience questionnaires were filled in.

Results

Ten pwCFs from two CF centers in Israel were included. The mean age was 31.5 years (range 15-74 years); eight were taking ETI and two TI. Median adherence to CFTRm was 97.5% (range 70%-100%) in the first year and 94% (range 84%-99%) in the second year, which is higher than the previously reported CFTRm adherence of ∼80%. No adverse events related to the use of the platform were reported. Patients reported ReX to be valuable to their treatment management and user friendly. Estimated mean forced expiratory volume in 1 s (FEV1%) increased from 74.4% to 80.8% (p = 0.004) over 2 years. Similarly, estimated BMI percentile increased from 53.5 to 59.0 (p < 0.001).

Conclusions

Using the ReX platform in medication management of pwCF treated by CFTRm is safe, easy to use, and effective in improving the adherence to treatment and the clinical outcomes. Consequently, this device may potentially reduce costs to healthcare providers. Further larger and long-term studies are required to examine the clinical benefits of the ReX platform.

Partners in research: The success with therapies research consortium and the CF community unite to improve self-management

BACKGROUND

The daily treatment regimen for an individual with cystic fibrosis (CF) can take more than 2 h to complete, and chronic treatment adherence rates are low. Developing partnerships between CF clinical researchers and the CF community is essential in developing acceptable, feasible, and effective strategies to improve self-management and adherence.

METHODS

The Success with Therapies Research Consortium (STRC) was formed as a multi-center US collaborative to conduct rigorous research studies of adherence to CF treatments. A multidisciplinary team of researchers from 15 sites, collaborating with members of the CF community, is charged with developing, implementing, and disseminating real-world, patient-centered interventions for people living with CF.

RESULTS

Since 2014, the STRC has conducted 8 studies. The CF community, people with CF (pwCF), and caregivers have come to serve in multiple valuable capacities on the STRC, including as members of the Steering Committee and Co-Principal Investigators. Additionally, while people with CF are irreplaceable participants in STRC studies, their influence, and that of their families and healthcare professionals, extends beyond the traditional research participant role.

CONCLUSIONS

Engaging broadly with the CF community is the optimal model for developing interventions to support those living with CF in sustaining daily care. Input and direct involvement from people with CF, their families, and their caregivers has enabled the STRC to advance its mission through innovative clinical research approaches.

Telemedicine and remote monitoring in cystic fibrosis

PURPOSE OF REVIEW

Guidelines for cystic fibrosis (CF) care recommend multidisciplinary teams see patients at least quarterly with frequent measurement of spirometry and collection of respiratory cultures. This can be burdensome for people with CF, particularly if they live far from a specialized care center. This has led to an interest in telehealth coupled with remote monitoring. We review the recent literature on these topics for people with CF.

RECENT FINDINGS

The COVID-19 pandemic accelerated a move toward remote delivery of CF care and multiple recent publications have reported on the feasibility of telehealth, remote spirometry, remote collection of respiratory cultures, adherence monitoring, cough assessment, symptom monitoring and activity tracking. Useful data can be obtained and both clinicians and patients have favorable opinions about remote delivery of healthcare, though the impact on clinical outcomes is not yet known.

SUMMARY

Telehealth and remote monitoring for people with CF is feasible and has grown in use, though it is too early to know how prominently these approaches will fit into routine care for CF.

Post-approval studies with the CFTR modulators Elexacaftor-Tezacaftor—Ivacaftor

Triple combination therapy with the CFTR modulators elexacaftor (ELX), tezacaftor (TEZ) and ivacaftor (IVA) has been qualified as a game changer in cystic fibrosis (CF). We provide an overview of the body of literature on ELX/TEZ/IVA published between November 2019 and February 2023 after approval by the regulators. Recombinant ELX/TEZ/IVA-bound Phe508del CFTR exhibits a wild type conformationin vitro, but in patient’s tissue a CFTR glyoisoform is synthesized that is distinct from the wild type and Phe508del isoforms. ELX/TEZ/IVA therapy improved the quality of life of people with CF in the real-life setting irrespective of their anthropometry and lung function at baseline. ELX/TEZ/IVA improved sinonasal and abdominal disease, lung function and morphology, airway microbiology and the basic defect of impaired epithelial chloride and bicarbonate transport. Pregnancy rates were increasing in women with CF. Side effects of mental status changes deserve particular attention in the future.

Simultaneous Quantification of Ivacaftor, Tezacaftor, and Elexacaftor in Cystic Fibrosis Patients' Plasma by a Novel LC-MS/MS Method

The new breakthrough cystic fibrosis (CF) drug combination of ivacaftor (IVA), tezacaftor (TEZ), and elexacaftor (ELX), namely "caftor" drugs, directly modulates the activity and trafficking of the defective CF transmembrane conductance regulator protein (CFTR) underlying the CF disease. The role of therapeutic drug monitoring (TDM) of caftor drugs in clinical settings has recently been established. The availability of reliable and robust analytical methods for the quantification of IVA, TEZ, and ELX is essential to support dose-concentration-effect studies. We have developed and validated a new liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the rapid and simultaneous quantification of IVA, TEZ, and ELX from the plasma of CF patients. The method was based on a rapid extraction protocol from 50 μL human plasma and separation on a reversed-phase C-18 HPLC column after the addition of deuterated internal standards. Accurate analyte quantification using multiple reaction monitoring (MRM) detection was then obtained using a Thermofisher Quantiva triple-quadrupole MS coupled to an Ultimate 3000 UHPLC. The method has been validated following international (EMA) guidelines for bioanalytical method validation and has been tested on plasma samples from 62 CF patients treated with the three-drug combination IVA/TEZ/ELX, marketed as Kaftrio^® or Trikafta^®, in steady-state condition. The assay was linear over wide concentration ranges (0.008-12 mg/L) in plasma for IVA, TEZ, and ELX, suitable for a broad range of plasma concentrations, and accurate and reproducible in the absence of matrix effects. The stability of analytes for at least 30 days at room temperature could allow for cost-effective shipment and storage. On the same day of sample collection, a sweat test was evaluated for 26 associated patients' samples, FEV1 (%) for 58, and BMI was calculated for 62. However, Spearman correlation showed no correlation between C_through plasma concentrations of analytes (IVA, TEZ, ELX) and sweat test, FEV1 (%), or BMI. Our method proved to be suitable for TDM and could be helpful in assessing dose-concentration-response correlations in larger studies.

Future therapies for cystic fibrosis

We are currently witnessing transformative change for people with cystic fibrosis with the introduction of small molecule, mutation-specific drugs capable of restoring function of the defective protein, cystic fibrosis transmembrane conductance regulator (CFTR). However, despite being a single gene disorder, there are multiple cystic fibrosis-causing genetic variants; mutation-specific drugs are not suitable for all genetic variants and also do not correct all the multisystem clinical manifestations of the disease. For many, there will remain a need for improved treatments. Those patients with gene variants responsive to CFTR modulators may have found these therapies to be transformational; research is now focusing on safely reducing the burden of symptom-directed treatment. However, modulators are not available in all parts of the globe, an issue which is further widening existing health inequalities. For patients who are not suitable for- or do not have access to- modulator drugs, alternative approaches are progressing through the trials pipeline. There will be challenges encountered in design and implementation of these trials, for which the established global CF infrastructure is a major advantage. Here, the Cystic Fibrosis National Research Strategy Group of the UK NIHR Respiratory Translational Research Collaboration looks to the future of cystic fibrosis therapies and consider priorities for future research and development.

Longitudinal Study of Therapeutic Adherence in a Cystic Fibrosis Unit: Identifying Potential Factors Associated with Medication Possession Ratio

Cystic fibrosis (CF) is a genetic and multisystemic disease that requires a high therapeutic demand for its control. The aim of this study was to assess therapeutic adherence (TA) to different treatments to study possible clinical consequences and clinical factors influencing adherence. This is an ambispective observational study of 57 patients aged over 18 years with a diagnosis of CF. The assessment of TA was calculated using the Medication Possession Ratio (MPR) index. These data were related to exacerbations and the rate of decline in FEV1 percentage. Compliance was good for all CFTR modulators, azithromycin, aztreonam, and tobramycin in solution for inhalation. The patients with the best compliance were older; they had exacerbations and the greatest deterioration in lung function during this period. The three variables with the highest importance for the compliance of the generated Random Forest (RF) models were age, FEV1%, and use of Ivacaftor/Tezacaftor. This is one of the few studies to assess adherence to CFTR modulators and symptomatic treatment longitudinally. CF patient therapy is expensive, and the assessment of variables with the highest importance for a high MPR, helped by new Machine learning tools, can contribute to defining new efficient TA strategies with higher benefits.

Therapeutic Drug Monitoring of Ivacaftor, Lumacaftor, Tezacaftor, and Elexacaftor in Cystic Fibrosis: Where Are We Now?

Drugs modulating the cystic fibrosis transmembrane conductance regulator (CFTR) protein, namely ivacaftor, lumacaftor, tezacaftor, and elexacaftor, are currently revolutionizing the management of patients with cystic fibrosis (CF), particularly those with at least one F508del variant (up to 85% of patients). These “caftor” drugs are mainly metabolized by cytochromes P450 3A, whose enzymatic activity is influenced by environmental factors, and are sensitive to inhibition and induction. Hence, CFTR modulators are characterized by an important interindividual pharmacokinetic variability and are also prone to drug–drug interactions. However, these CFTR modulators are given at standardized dosages, while they meet all criteria for a formal therapeutic drug monitoring (TDM) program that should be considered in cases of clinical toxicity, less-than-expected clinical response, drug or food interactions, distinct patient subgroups (i.e., pediatrics), and for monitoring short-term adherence. While the information on CFTR drug exposure–clinical response relationships is still limited, we review the current evidence of the potential interest in the TDM of caftor drugs in real-life settings.

The indispensable role of pharmacy services and medication therapy management in cystic fibrosis

Care for people with cystic fibrosis (PWCF) is highly complex and requires a multidisciplinary approach where the pharmacist plays a vital role. The purpose of this manuscript is to serve as a guideline for pharmacists and pharmacy technicians who provide care for PWCF by providing background and current recommendations for the use of cystic fibrosis (CF)-specific medications in both the acute and ambulatory care settings. The article explores current literature surrounding the role of pharmacists and pharmacy technicians, proven pharmacy models to emulate, and pharmacokinetic idiosyncrasies unique to the CF population while also identifying areas of future research. Clinical recommendations for the use of CF-specific medications are broken down by organ system including mechanism of action, adverse events, dosages, and monitoring parameters. The article also includes quick reference tables essential to the acute and chronic medication therapy management of PWCF.

Triple combination cystic fibrosis transmembrane conductance regulator modulator therapy in the real world - opportunities and challenges

PURPOSE OF REVIEW

The purpose of this review is to describe on-going and upcoming real-world studies that will aid the cystic fibrosis (CF) community in understanding the long-term efficacy, safety and challenges in utilizing this therapy and managing care.

RECENT FINDINGS

The triple combination of elexacaftor, tezacaftor and ivacaftor (ETI) has been demonstrated to improve lung function, weight and quality of life in children and adults with CF with at least one copy of Phe508del. Treatment with ETI will potentially be available for approximately 90% of the CF population and change the face of CF.

SUMMARY

In spite of early demonstrations of short-term efficacy and safety, for medications that may be given for much of someone's life, continued assessment of these outcomes is necessary. Furthermore, the CF community must evaluate and address the issues that arise with increased longevity including parenthood, preventive care management and the potential comorbidities of aging.