VX-445 (ELEXACAFTOR)/TEZACAFTOR/IVACAFTOR  

“TRIKAFTA” (USA)          “KAFTRIO” (UK)

2018

2018 Keating DMarigowda GBurr LDaines CMall MAMcKone EFRamsey BWRowe SMSass LATullis EMcKee CMMoskowitz SMRobertson SSavage JSimard CVan Goor FWaltz DXuan FYoung TTaylor-Cousar JLVX16-445-001 Study Group.  VX-445-Tezacaftor-Ivacaftor in Patients with Cystic Fibrosis and One or Two Phe508del Alleles  N Engl J Med. 2018 Oct 25;379(17):1612-1620. doi: 10.1056/NEJMoa1807120. Epub  2018 Oct 18. [Pubmed]

Dominic Keating

VX-445 is a next-generation cystic fibrosis transmembrane conductance regulator (CFTR) corrector designed to restore Phe508del CFTR protein function in patients with cystic fibrosis when administered with tezacaftor and ivacaftor (VX-445-tezacaftor-ivacaftor).                                                     The authors evaluated the effects of VX-445-tezacaftor-ivacaftor on Phe508del CFTR protein processing, trafficking, and chloride transport in human bronchial epithelial cells. On the basis of in vitro activity, a randomized, placebo-controlled, double-blind, dose-ranging, phase 2 trial was conducted to evaluate oral VX-445-tezacaftor-ivacaftor in patients heterozygous for the Phe508del CFTR mutation and a minimal-function mutation (Phe508del-MF) and in patients homozygous for the Phe508del CFTR mutation (Phe508del-Phe508del) after tezacaftor-ivacaftor run-in. Primary end points were safety and absolute change in percentage of predicted forced expiratory volume in 1 second (FEV1) from baseline.

Results. In vitro, VX-445-tezacaftor-ivacaftor significantly improved Phe508del CFTR protein processing, trafficking, and chloride transport to a greater extent than any two of these agents in dual combination.   In patients with cystic fibrosis, VX-445-tezacaftor-ivacaftor had an acceptable safety and side-effect profile. Most adverse events were mild or moderate. The treatment also resulted in an increased percentage of predicted FEV1 of up to 13.8 points in the Phe508del-MF group (P<0.001). In patients in the Phe508del-Phe508del group, who were already receiving tezacaftor-ivacaftor, the addition of VX-445 resulted in an 11.0-point increase in the percentage of predicted FEV1 (P<0.001). In both groups, there was a decrease in sweat chloride concentrations and improvement in the respiratory domain score on the Cystic Fibrosis Questionnaire-Revised.

The authors concluded the use of VX-445-tezacaftor-ivacaftor to target Phe508del CFTR protein resulted in increased CFTR function in vitro and translated to improvements in patients with cystic fibrosis with one or two Phe508del alleles. This approach has the potential to treat the underlying cause of cystic fibrosis in approximately 90% of patients.     (Clinical trials NCT03227471 ; and EudraCT number, 2017-000797-11)

Dominic T Keating is Respiratory Physician at the Alfred Hospital · Department of Allergy, Immunology & Respiratory Medicine (AIRmed)  Australia, Melbourne

2019

Middleton PG,  Mall MA, Drevinek P, Lands LC, McKone EF, Polineni D, Ramsay BW, Taylor0Cousar JL, Tullis E, Vermeulen F, marifwada G, Mosowski SM, Nair N, Savage J, Simard C, Tian S, Waltz D, Xuan F, Jain Rassha for the VX17-445-i102 Study Group.  Elexacaftor-tezacaftor-iavacaftor for cystic fibrosis with a single The 508del allele. N Eng J Med 2019; 381:1809-19. [Pubmed]

             Peter Middleton

Cystic fibrosis is caused by mutations in the gene encoding the cystic fibrosis transmembrane conductance regulator (CFTR) protein, and nearly 90% of patients have at least one copy of the Phe508del CFTR mutation. In a phase 2 trial involving patients who were heterozygous for the Phe508del CFTR mutation and a minimal- function mutation (Phe508del–minimal function genotype), the next-generation CFTR corrector elexacaftor, in combination with tezacaftor and ivacaftor, improved Phe508del CFTR function and clinical outcomes. 

The authors conducted a phase 3, randomised, double-blind, placebo-controlled trial to confirm the efficacy and safety of elexacaftor–tezacaftor–ivacaftor in patients 12 years of age or older with cystic fibrosis with Phe508del–minimal function geno- types. Patients were randomly assigned to receive elexacaftor–tezacaftor–ivacaftor or placebo for 24 weeks. The primary end point was absolute change from baseline in percentage of predicted forced expiratory volume in 1 second (FEV1) at week 4. 

A total of 403 patients underwent randomisation and received at least one dose of active treatment or placebo. Elexacaftor–tezacaftor–ivacaftor, relative to placebo, resulted in a percentage of predicted FEV1 that was 13.8 points higher at 4 weeks and 14.3 points higher through 24 weeks, a rate of pulmonary exacerbations that was 63% lower, a respiratory domain score on the Cystic Fibrosis Questionnaire– Revised (range, 0 to 100, with higher scores indicating a higher patient-reported quality of life with regard to respiratory symptoms; minimum clinically important difference, 4 points) that was 20.2 points higher, and a sweat chloride concentration that was 41.8 mmol per litre lower (P<0.001 for all comparisons). Elexacaftor– tezacaftor–ivacaftor was generally safe and had an acceptable side-effect profile. Most patients had adverse events that were mild or moderate. Adverse events leading to discontinuation of the trial regimen occurred in 1% of the patients in the elexacaftor–tezacaftor–ivacaftor group.

Conclusion – Elexacaftor–tezacaftor–ivacaftor was efficacious in patients with cystic fibrosis with Phe508del–minimal function genotypes, in whom previous CFTR modulator regimens were ineffective. (VX17-445-102 ClinicalTrials.gov number, NCT03525444.) 

Professor Peter Middleton is Clinical Professor of Respiratory and Sleep Medicine Westmead  Hospital and CF Research Group, Ludwig Engel Centre for Respiratory Research, University of Sydney.

Heijerman HGM, McKone EF, Downey DG, Van Braeckel E, Rowe SM, Tullis E Mall MA, Welter JJ, Ramsey BW, McKee CM, Marigowda G, Moskowitz SM, Waltz D, Sosnay PR, Simard C, Ahluwalia N, Xuan F, Zhang Y, Taylor-Cousar JL, McCoy KS; VX17-445-103 Trial Group.  Efficacy and safety of the elexacaftor plus tezacaftor plus ivacaftor combination regimen in people with cystic fibrosis homozygous for the F508del mutation: a double-blind, randomised, phase 3 trial.   Collaborators (45).  Lancet. 2019 Oct 30. pii: S0140-6736(19)32597-8. doi: 10.1016/S0140-6736(19)32597-8. [Epub ahead of print]  Full copy available  [Pubmed]

           Harry Heijerman

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators correct the basic defect caused by CFTR mutations. Improvements in health outcomes have been achieved with the combination of a CFTR corrector and potentiator in people with cystic fibrosis homozygous for the F508del mutation. The addition of elexacaftor (VX-445), a next-generation CFTR corrector, to tezacaftor plus ivacaftor further improved F508del-CFTR function and clinical outcomes in a phase 2 study in people with cystic fibrosis homozygous for the F508del mutation.

This phase 3, multicentre, randomised, double-blind, active-controlled trial of elexacaftor in combination with tezacaftor plus ivacaftor was done at 44 sites in four countries. Eligible participants were those with cystic fibrosis homozygous for the F508del mutation, aged 12 years or older with stable disease, and with a percentage predicted forced expiratory volume in 1 s (ppFEV1) of 40-90%, inclusive. After a 4-week tezacaftor plus ivacaftor run-in period, participants were randomly assigned (1:1) to 4 weeks of elexacaftor 200 mg orally once daily plus tezacaftor 100 mg orally once daily plus ivacaftor 150 mg orally every 12 h versus tezacaftor 100 mg orally once daily plus ivacaftor 150 mg orally every 12 h alone. The primary outcome was the absolute change from baseline (measured at the end of the tezacaftor plus ivacaftor run-in) in ppFEV1 at week 4. Key secondary outcomes were absolute change in sweat chloride and Cystic Fibrosis Questionnaire-Revised respiratory domain (CFQ-R RD) score. This study is registered with ClinicalTrials.gov, NCT03525548.

Between Aug 3 and Dec 28, 2018, 113 participants were enrolled. Following the run-in, 107 participants were randomly assigned (55 in the elexacaftor plus tezacaftor plus ivacaftor group and 52 in the tezacaftor plus ivacaftor group) and completed the 4-week treatment period. The elexacaftor plus tezacaftor plus ivacaftor group had improvements in the primary outcome of ppFEV1 (least squares mean [LSM] treatment difference of 10·0 percentage points [95% CI 7·4 to 12·6], p<0·0001) and the key secondary outcomes of sweat chloride concentration (LSM treatment difference -45·1 mmol/L [95% CI -50·1 to -40·1], p<0·0001), and CFQ-R RD score (LSM treatment difference 17·4 points [95% CI 11·8 to 23·0], p<0·0001) compared with the tezacaftor plus ivacaftor group. The triple combination regimen was well tolerated, with no discontinuations. Most adverse events were mild or moderate; serious adverse events occurred in two (4%) participants receiving elexacaftor plus tezacaftor plus ivacaftor and in one (2%) receiving tezacaftor plus ivacaftor.

The authors concluded Elexacaftor plus tezacaftor plus ivacaftor provided clinically robust benefit compared with tezacaftor plus ivacaftor alone, with a favourable safety profile, and shows the potential to lead to transformative improvements in the lives of people with cystic fibrosis who are homozygous for the F508del mutation.

Dr Harry Heijerman is at the Department of Pulmonology, University Medical Center Utrecht, Utrecht, Netherlands.

Hoy SM. Elexacaftor/Ivacaftor/Tezacaftor: First Approval.  Drugs. 2019 Nov 29. doi: 10.1007/s40265-019-01233-7. [Epub ahead of print]Author information.[Pubmed]
A fixed-dose combination tablet of the cystic fibrosis transmembrane conductance regulator (CFTR) corrector tezacaftor and the CFTR potentiator ivacaftor with the next-generation CFTR corrector elexacaftor (hereafter referred to as elexacaftor/ivacaftor/tezacaftor) [Trikafta™] has been developed by Vertex Pharmaceuticals Inc. to treat patients with the most common cystic fibrosis mutation (F508del). Its use has been associated with statistically significant and/or clinically meaningful improvements in lung function and respiratory-related quality of life compared with comparator regimens (placebo or ivacaftor/tezacaftor) in multinational phase II and III studies, and in October 2019 elexacaftor/ivacaftor/tezacaftor was approved by the US FDA for the treatment of cystic fibrosis in patients aged ≥ 12 years who have ≥ 1 F508del mutation in the CFTR gene. A regulatory assessment for elexacaftor/ivacaftor/tezacaftor as a treatment for cystic fibrosis is underway in the EU. This article summarises the milestones in the development of elexacaftor/ivacaftor/tezacaftor leading to this first approval for the treatment of cystic fibrosis in patients aged ≥ 12 years who have ≥ 1 F508del mutation in the CFTR gene.

Dr S M Hoy is at Springer Nature, Private Bag 65901, Mairangi Bay, Auckland

2020

New Drug Hailed as Major Breakthrough in Cystic Fibrosis. Am J Med Genet A. 2020 Jan;182(1):8-9. doi: 10.1002/ajmg.a.61420.[Pubmed] This is my summary as their is no abstract:  No authors are listed for this neat account of the progress in the development of CFTR modulator therapy from the FDA approval of ivacaftor (VX-771) in January 2012 for patients with one copy of the G551D mutation, to Orkambi, the combination of lumacaftor (VX-809) and ivacaftor, for those with 2 copies of the F508del mutation in 2015, to another drug combination of tezacaftor (VX-661) and ivacaftor (Symdeko) in 2018 for those people with at least one F508del mutation.

In 2019 the combination drug Trikafta, combining elexacaftor (VX-445), ivacaftor (Kalydeco) and tezacaftor (VX-661), was approved for patients aged 12 years and over with at least one F508del – a group comprising some 90% of the CF population. Approval was based on two phase III clinical trials (Middleton et al, 2019; Heijerman et al, 2019).  Sadly these drugs are very expensive and funding is and will remain a major problem.

DiMango E, Overdevest J, Keating C, Francis SF, Dansky D, Gudis D.  Effect of highly effective modulator treatment on sinonasal symptoms in cysticfibrosis.  J Cyst Fibros. 2020 Jul 18:S1569-1993(20)30794-3. doi: 10.1016/j.jcf.2020.07.002. Online ahead of print. [Pubmed]

Emily DiMango

Elexacaftor-tezacaftor-ivacaftor is a highly effective modulator for cystic fibrosis (CF) patients homozygous or heterozygous for F508del. Effects of the drug on sinonasal symptoms have not been studied    Adult participants were prospectively evaluated at baseline and after three months of treatment using validated questionnaires assessing sinonasal symptoms (SNOT-22) and CF-related quality of life (CFQ-R).
Results: Forty-three participants completed the study; 23 were taking other CF transmembrane conductance (CFTR) modulators at the time of study participation. There was a significant improvement in mean SNOT-22 from 34.8 (29.4-40, 95% confidence interval) to 24.4 (19.9-29.0) (p = 0.000003) and in the Respiratory domain of the CFQR from 60.6 (57.1-64.1) to 83.3 (79.4-87.2) (p = 0.0000002), both achieving a minimal clinically important difference. Patients previously taking CFTR modulators experienced a greater benefit in sinonasal and respiratory symptoms

Conclusions: Elexacaftor-tezacaftor-ivacaftor is associated with significant improvement in sinonasal symptoms; previous use of CFTR modulators is associated with greater benefit

Dr Emily DiMango is Professor of Medicine at Columbia University Medical Center; Director, John Edsall-John Wood Asthma Center; Director, Adult Cystic Fibrosis Program

Onofrio LaselvaClaire BartlettTarini N A GunawardenaHong OuyangPaul D W EckfordTheo J Moraes Christine E Bear Tanja Gonska Rescue of multiple class II CFTR mutations by elexacaftor+ tezacaftor+ivacaftor mediated in part by the dual activities of Elexacaftor as both corrector and potentiator.  Eur Respir J 2020 Dec 10;2002774.doi: 10.1183/13993003.02774-2020. Online ahead of print.
Positive results in preclinical studies of the triple combination of elexacaftor, tezacaftor and ivacaftor, performed in airway epithelial cell cultures obtained from patients harboring F508del-CFTR, translated to impressive clinical outcomes for subjects carrying this mutation in clinical trials and approval of TRIKAFTATM Encouraged by this correlation, we were prompted to evaluate the effect of the elexacaftor, tezacaftor and ivacaftor triple combination on primary nasal epithelial cultures obtained from individuals with rare Class II cystic fibrosis causing mutations; G85E, M1101K and N1303K for which TRIKAFTATM is not approved. Cultures from individuals homozygous for M1101K responded better than cultures harboring G85E and N1303K after treatment with the triple combination with respect to improvement in regulated channel function and protein processing. A similar genotype specific effect of the triple combination was observed when the different mutations were expressed in HEK-293 cells, supporting the hypothesis that these modulators may act directly on the mutant proteins. Detailed studies in nasal cultures and HEK-293 cells showed that the corrector: elexacaftor, exhibited dual activity as both corrector and potentiator and suggested that the potentiator activity contributes to its pharmacological activity. These preclinical studies using nasal epithelial cultures identified mutation genotypes for which elexacaftor, tezacaftor and ivacaftor may produce clinical responses that are comparable to, or inferior to those observed for F508del-CFTR.

Onofrio Laselva is with the Programme in Molecular Medicine, Hospital for Sick Children, Toronto, Canada and the Department of Physiology University of Toronto

Scott A KannerZunaira ShujaPapiya ChoudhuryAnanya JainHenry M Colecraft.  Targeted deubiquitination rescues distinct trafficking-deficient ion channelopathies. Nat Methods    2020 Dec;17(12):1245-1253.doi: 10.1038/s41592-020-00992-6. Epub 2020 Nov 9. [Pubmed]

        Scott Kanner

Impaired protein stability or trafficking underlies diverse ion channelopathies and represents an unexploited unifying principle for developing common treatments for otherwise dissimilar diseases. Ubiquitination limits ion channel surface density, but targeting this pathway for the purposes of basic study or therapy is challenging because of its prevalent role in proteostasis. We developed engineered deubiquitinases (enDUBs) that enable selective ubiquitin chain removal from target proteins to rescue the functional expression of disparate mutant ion channels that underlie long QT syndrome (LQT) and cystic fibrosis (CF). In an LQT type 1 (LQT1) cardiomyocyte model, enDUB treatment restored delayed rectifier potassium currents and normalized action potential duration. CF-targeted enDUBs synergistically rescued common (ΔF508) and pharmacotherapy-resistant (N1303K) CF mutations when combined with the US Food and Drug Administation (FDA)-  approved drugs Orkambi (lumacaftor/ivacaftor) and Trikafta (elexacaftor/tezacaftor/ivacaftor and ivacaftor). Altogether, targeted deubiquitination via enDUBs provides a powerful protein stabilization method that not only corrects diverse diseases caused by impaired ion channel trafficking, but also introduces a new tool for deconstructing the ubiquitin code in situ

Scott A Kanner  is on the Doctoral Program in Neurobiology and Behavior, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA.

Onofrio LaselvaJacqueline McCormackClaire BartlettWan IpTarini N A GunawardenaHong OuyangPaul D W EckfordTanja GonskaTheo J MoraesChristine E Bear.  Preclinical Studies of a Rare CF-Causing Mutation in the Second Nucleotide Binding Domain (c.3700A>G) Show Robust Functional Rescue in Primary Nasal Cultures by Novel CFTR Modulators.  J Pers Med   2020 Nov 5;10(4):209.doi: 10.3390/jpm10040209.  Free PMC article [Pubmed]

Onofrio Laselva

The combination therapies ORKAMBITM and TRIKAFTATM are approved for people who have the F508del mutation on at least one allele. In this study we examine the effects of potentiator and corrector combinations on the rare mutation c.3700A>G. This mutation produces a cryptic splice site that deletes six amino acids in NBD2 (I1234-R1239del). Like F508del it causes protein misprocessing and reduced chloride channel function. We show that a novel cystic fibrosis transmembrane conductance regulator CFTR modulator triple combination (AC1, corrector, AC2-2, co-potentiator and AP2, potentiator), rescued I1234-R1239del-CFTR activity to WT-CFTR level in HEK293 cells. Moreover, we show that although the response to ORKAMBI was modest in nasal epithelial cells from two individuals homozygous for I1234-R1239del-CFTR, a substantial functional rescue was achieved with the novel triple combination. Interestingly, while both the novel CFTR triple combination and TRIKAFTATM treatment showed functional rescue in gene-edited I1234-R1239del-CFTR-expressing HBE cells and in nasal cells from two CF patients heterozygous for I1234-R1239del/W1282X, nasal cells homozygous for I1234-R1239del-CFTR showed no significant response to the TRIKAFTATMcombination. These data suggest a potential benefit of CFTR modulators on the functional rescue of I1234-R1239del -CFTR, which arises from the rare CF-causing mutation c.3700A>G, and highlight that patient tissues are crucial to our full understanding of functional rescue in rare CFTR mutations.

Onofrio Laselva at the Programme in Molecular Medicine, Hospital for Sick Children, Toronto, ON M5G 8X4, Canada and the Department of Physiology, University of Toronto, Toronto, ON M5G 8X4, Canada

      Guido Veit

Guido VeitAriel RoldanMark A HancockDillon F Da FonteHaijin XuMaytham HusseinSaul FrenkielElias MatoukTony VelkovGergely L Lukacs .  Allosteric folding correction of F508del and rare CFTR mutants by elexacaftor-tezacaftor-ivacaftor (Trikafta) combination. JCI Insight 2020 Sep 17;5(18):e139983.doi: 10.1172/jci.insight.139983. Free PMC article [Pubmed]
Based on its clinical benefits, Trikafta – the combination of folding correctors VX-661 (tezacaftor), VX-445 (elexacaftor), and the gating potentiator VX-770 (ivacaftor) – was FDA approved for treatment of patients with cystic fibrosis (CF) carrying deletion of phenylalanine at position 508 (F508del) of the CF transmembrane conductance regulator (CFTR) on at least 1 allele.
Neither the mechanism of action of VX-445 nor the susceptibility of rare CF folding mutants to Trikafta are known. Here, we show that, in human bronchial epithelial cells, VX-445 synergistically restores F508del-CFTR processing in combination with type I or II correctors that target the nucleotide binding domain 1 (NBD1) membrane spanning domains (MSDs) interface and NBD2, respectively, consistent with a type III corrector mechanism. This inference was supported by the VX-445 binding to and unfolding suppression of the isolated F508del-NBD1 of CFTR. The VX-661 plus VX-445 treatment restored F508del-CFTR chloride channel function in the presence of VX-770 to approximately 62% of WT CFTR in homozygous nasal epithelia. Substantial rescue of rare misprocessing mutations (S13F, R31C, G85E, E92K, V520F, M1101K, and N1303K), confined to MSD1, MSD2, NBD1, and NBD2 of CFTR, was also observed in airway epithelia, suggesting an allosteric correction mechanism and the possible application of Trikafta for patients with rare misfolding mutants of CFTR.

Dr Guido Veit is in the Department of Physiology and.2SPR-MS Facility, McGill University, Montréal, Quebec, Canada.

William TindellAmanda SuSarah M Oros, Abner O RayapatiGopalkumar Rakesh. Trikafta and Psychopathology in Cystic Fibrosis: A Case Report.  Psychosomatics  Nov-Dec 2020;61(6):735-738.doi: 10.1016/j.psym.2020.06.021. Epub 2020 Jul 2.     [Pubmed]

William Tindell

Abstract requested but not available.

Dr William Tindell is a resident in the Department of Psychiatry, University of Kentucky Medical Center, Lexington, KY

Nazan ÇobanoğluUğur ÖzçelikErkan ÇakırTuğba Şişmanlar EyüboğluSevgi PekcanGüzin Cinel.et al.  Patients eligible for modulator drugs: Data from cystic fibrosis registry of Turkey. Pediatr Pulmonol 2020 Sep;55(9):2302-2306.doi: 10.1002/ppul.24854. Epub 2020 May 26.[Pubmed]

     Nazan Cobanoglu

Background: A better understanding of cystic fibrosis transmembrane conductance regulator biology has led to the development of modulator drugs such as ivacaftor, lumacaftor-ivacaftor, tezacaftor-ivacaftor, and elexacaftor-tezacaftor-ivacaftor. This cross-sectional study evaluated cystic fibrosis (CF) patients eligible for modulator drugs.
Methods: Data for age and genetic mutations from the Cystic Fibrosis Registry of Turkey collected in 2018 were used to find out the number of patients who are eligible for modulator therapy.
Results: Of registered 1488 CF patients, genetic analysis was done for 1351. The numbers and percentages of patients and names of the drugs, that the patients are eligible for, are as follows: 122 (9.03%) for ivacaftor, 156 (11.54%) for lumacaftor-ivacaftor, 163 (11.23%) for tezacaftor-ivacaftor, and 57 (4.21%) for elexacaftor-tezacaftor-ivacaftor. Among 1351 genotyped patients total of 313 (23.16%) patients are eligible for currently licensed modulator therapies (55 patients were shared by ivacaftor and tezacaftor-ivacaftor, 108 patients were shared by lumacaftor-ivacaftor and tezacaftor-ivacaftor, and 22 patients were shared by tezacaftor-ivacaftor and elexacaftor-tezacaftor-ivacaftor groups).
Conclusions: The present study shows that approximately one-fourth of the registered CF patients in Turkey are eligible for modulator drugs. As, frequent mutations that CF patients have in Turkey are different from North American developing countries like Turkey is noteworthy and European CF patients, developing modulator drugs effective for those mutations is necessary. Furthermore, as modulator drugs are very expensive currently, financial support of the government in developing countries like Turkey is noteworthy

Prof. Dr Fatama Nazan Çobanoğlu is at the Division of Pediatric Pulmonology, Faculty of Medicine, Ankara University, Ankara, Turkey.

Shannon M RotoloStephanie DuehlmeyerSarah M SlackHollyann R JacobsBrian Heckman. Testicular pain following initiation of elexacaftor/tezacaftor/ivacaftor in males with cystic fibrosis.  J Cyst Fibros  2020 Sep;19(5):e39-e41.doi: 10.1016/j.jcf.2020.04.017.Epub 2020 May 27. [Pubmed]

   Shannon Rotolo

There were no documented reports of testicular pain during clinical trials. In this case series, we discuss 7 males between 17 and 39 years of age who reported testicular pain or discomfort within the first two weeks of starting therapy. The precise mechanism of this side effect is unknown, but it may be related to restoration of CFTR function in the male reproductive tract. All patients experienced resolution of this side effect within a week after onset, regardless of the management, except for one. Further research is needed to determine short- and long-term impact of this drug on male fertility. Until more data is available, the authors recommend counselling patients on contraceptive options.

Shannon M Rotolo is Clinical Pharmacy Specialist at the University of Chicago Medicine, Department of Pharmacy, Chicago, IL

2021

Kate M O’Shea Orla M O’CarrollCatherine CarrollBrenda GroganAnna ConnollyLynda O’ShaughnessyTrevor T NicholsonCharles G GallagherEdward F McKone.   Efficacy of elexacaftor/tezacaftor/ivacaftor in patients with cystic fibrosis and advanced lung diseaseEur Respir J. 2021 Feb 25;57(2):2003079.doi: 10.1183/13993003.03079-2020. Print 2021 Feb. [Pubmed]

Kate O’Shea

No abstract but the following abstract form the article – This study shows that ELX/TEZ/IVA improves multiple outcome measures in a small cohort of 14 patients with advanced CF lung disease attending a single centre and that these improvements are similar to those seen in patients with milder disease.
Follow-up measurement dates varied with mean repeat FEV1 at 26.4±4.2 days, mean BMI at 62±35 days and mean SwCl at 64±84 days after ELX/TEZ/IVA initiation. After treatment with ELX/TEX/IVA, FEV1 improved (27.3±7.3% pred versus 36.3±16.5% pred; p<0.0001). BMI also improved (20.7±3.6 versus 22.1±3.4 kg·m−2; p<0.0001). Sweat chloride results were only available for 11 patients, mainly due to insufficient sweat volume despite multiple attempts, but also revealed significant improvement (104.9±15.04 versus 53.6±23.3 mmol·L−1; p<0.0001). Infective exacerbations requiring hospitalisation reduced in frequency (0.28±0.17 exacerbations per month in 12 months prior versus 0.04±0.07 exacerbations per month during follow-up period of 4.9 months; p<0.001)
Most significant were the reduction in requirement for intravenous antibiotic therapy as well as improvements in lung function and sweat chloride. These results were seen in both patients exposed to previous modulator therapies and in those who were CFTR modulator-naïve. There were few significant adverse events. This therapy is expected to improve the disease trajectory for many CF patients with at least one Phe508del mutation and this expectation should also apply to those groups with more advanced disease.

 Kate M O’Shea is studying at the School of Medicine, University College Dublin

Dr Orla M O’Carroll is a Respiratory Specialist Registrar in the Department of Respiratory medicine St Vincent’s University Hospital, Dublin

Guido VeitChristian VaccarinGergely L Lukacs.  Elexacaftor co-potentiates the activity of F508del and gating mutants of CFTR. J Cyst Fibros 2021 Mar 25;S1569-1993(21)00087-4.doi: 10.1016/j.jcf.2021.03.011.Online ahead of print. [Pubmed]

Guido Veit

Trikafta, the combination of elexacaftor (VX-445), tezacaftor (VX-661) and ivacaftor (VX-770), was approved for therapy of cystic fibrosis (CF) patients with at least one allele of the CFTR mutation F508del. While the corrector function of VX-445 is well established, here we investigated the putative potentiator activity of VX-445 alone and in combination with VX-770. Acute addition of VX-445 increased the VX-770-potentiated F508del- and G551D-CFTR current by ~24% and >70%, respectively, in human bronchial and nasal epithelia. Combinatorial profiling and cluster analysis of G551D- and G1244E-CFTR channel activation with potentiator pairs indicated a distinct VX-445 mechanism of action that is, at least, additive to previously identified potentiator classes, including the VX-770. Since VX-770 only partially normalizes the G551D-CFTR channel function and adult G551D patients still experience progressive loss of lung function, VX-445+VX-770 combination therapy could provide clinical benefit to CF patients with the G551D and other dual potentiator responsive mutants.

Dr Guido Veit is a Research Associate in the Department of Physiology, McGill University, Montréal, Canada. His main research interest: Epithelial biology with focus on the interplay between extracellular events (cytokines, extracellular matrix) and cellular responses (transmembrane proteins, signalling, transcriptional activation).

Jennifer L Taylor-CousarR Jain.  Maternal and fetal outcomes following elexacaftor-tezacaftor-ivacaftor use during pregnancy and lactation. J Cyst Fibros. 2021 Mar 21;S1569-1993(21)00055-2.doi: 10.1016/j.jcf.2021.03.006.Online ahead of print.  [Pubmed]

Jennifer Taylor-Cousar

There is currently no data in the literature regarding use of Elexacaftor-tezacaftor-ivacaftor (ETI) in pregnant women. Thus, the decision to continue therapy during pregnancy (with the associated unknown fetal impact) versus discontinuing therapy (with the known risk of maternal health decline) is challenging.
Methods: CF Center staff completed an anonymous questionnaire regarding pregnancy and infant outcomes for women who used ETI during pregnancy and/or lactation.
Results: Of 45 ETI-exposed pregnancies reported to date, complications in 2 mothers and in 3 infants (2 born to mothers with poorly controlled diabetes) were rated by clinicians as unknown (possible) or suspected relatedness to ETI use. Two women terminated unplanned pregnancies. Miscarriage rates were consistent with that known in the general U.S.
Population: Five of the six women who discontinued ETI out of concern for unknown foetal risk restarted because of clinical deterioration. No infant cataracts were reported though only two infants were formally evaluated.
Conclusions: In the context of the known increased rate of complications in women with CF and their infants, data from this retrospective survey is reassuring for women who choose to continue ETI during pregnancy. However, a large, multi-centre prospective study is needed to assess impact of use of ETI in pregnancy.

Dr Jennifer L Taylor-Cousar  is in the Departments of Medicine and Pediatrics, National Jewish Health, 1400 Jackson Street; J318, Denver, CO 80206.

– Evidence accumulating that there seems to be no serious consequences of taking ETI during pregnancy.

Edith T ZemanickJennifer L Taylor-CousarJane DaviesRonald L GibsonMarcus A MallEdward F McKone et al, A Phase 3 Open-Label Study of ELX/TEZ/IVA in Children 6 Through 11 Years of Age With CF and at Least One F508del Allele.  Am J Respir Crit Care Med 2021 Mar 18. doi: 10.1164/rccm.202102-0509OC.Online ahead of print.  [Pubmed]

Edith Zermanick

Rationale: Elexacaftor/tezacaftor/ivacaftor (ELX/TEZ/IVA) was shown to be efficacious and safe in patients aged 12 years and older with cystic fibrosis and at least one F508del-CFTR allele, but has not been evaluated in children <12 years of age.
Objectives: To assess the safety, pharmacokinetics, and efficacy of ELX/TEZ/IVA in children 6 through 11 years of age with F508del-minimal function or F508del-F508del genotypes.
Methods: In this 24-week open-label Phase 3 study, children (N=66) weighing <30 kg received 50% of the ELX/TEZ/IVA adult daily dose (ELX 100 mg once daily, TEZ 50 mg once daily, and IVA 75 mg every 12 hours) while children weighing ≥30 kg received the full adult daily dose (ELX 200 mg once daily, TEZ 100 mg once daily, and IVA 150 mg every 12 hours).
Measurements and main results: The primary endpoint was safety and tolerability. The safety and pharmacokinetic profiles of ELX/TEZ/IVA were generally consistent with those observed in older patients. The most common reported adverse events (AEs) included cough, headache, and pyrexia; in most of the children who had AEs, these were mild or moderate in severity. Through Week 24, ELX/TEZ/IVA treatment improved the ppFEV1 (10.2 percentage points; 95% confidence interval [CI], 7.9 to 12.6), Cystic Fibrosis Questionnaire-Revised respiratory domain score (7.0 points; 95% CI, 4.7 to 9.2), lung clearance index2.5 (-1.71 units; 95% CI, -2.11 to -1.30), and sweat chloride (-60.9 mmol/L; 95% CI, -63.7 to -58.2); body mass index-for-age z-score increased over the 24-week treatment period compared to the pre-treatment baselineds, UK

Conclusions: Our results show ELX/TEZ/IVA is safe and efficacious in children 6 through 11 years of age with at least one F508del-CFTR allele, supporting its use in this patient population.

Dr Edith T Zemanick is Associate Professor at the Colorado Anschutz Medical Campus and Children’s Hospital Colorado, Department of Pediatrics, Aurora, Colorado, United States

Julian StashowerPatrick CarrVirginia MillerBarrett ZlotoffNovel reaction to new cystic fibrosis medication TrikaftaClin Case Rep 2021 May 4;9(5):e04116.doi: 10.1002/ccr3.4116.eCollection 2021 May.  [Pubmed]      Free PMC article

Legs of patient

Julian Stashower

The authors describe a novel case of an urticaria multiforme-type drug reaction to the new cystic fibrosis medication Trikafta (elexacaftor + tezacaftor + ivacaftor). Equipped with this information, clinicians may be more prepared to counsel and treat patients if they experience similar symptoms after beginning Trikafta

There are more images in the Free PMC article

Dr Julian Stashower is at the University of  Virginia School of Medicine, Charlottesville USA

This is the first study assessing changes of airway inflammation on a day-to-day basis in CF patients receiving a newly administered CFTR-modulator therapy. It proves a decline of airway inflammation during ivacaftor-therapy.

Dr Jochen G Mainz is Professor at the Cystic Fibrosis Center, Brandenburg Medical School (MHB) University, Klinikum Westbrandenburg, Brandenburg an der Havel,, the CF-Center, Jena University Hospital, Jena and the Faculty of Health Sciences, Joint Faculty of the Brandenburg University of Technology Cottbus -Senftenberg, The Brandenburg Medical School Theodor Fontane and the University of Potsdam, Cottbus, Brandenburg an der Havel and Potsdam, Germany.

C MartinE BurnetA Ronayette-PreiraP de CarliJ MartinL DelmasB PrieurP-R BurgelPatient perspectives following initiation of elexacaftor-tezacaftor-ivacaftor in people with cystic fibrosis and advanced lung diseaseRespir Med Res. 2021 May 17;80:100829.doi: 10.1016/j.resmer.2021.100829.Online ahead of print.  [Pubmed]
Backgound: Elexacaftor-tezacaftor-ivacaftor partially restores cystic fibrosis transmembrane conductance regulator function, and has been shown to induce significant clinical improvement in patients with at least one Phe508del allele. Yet little data exist on patient perspectives following elexacaftor-tezacaftor-ivacaftor initiation.
Methods: A mixed methods study was conducted using an online 13-item questionnaire (including 9 closed questions and 4 open questions), submitted from July 10th to August 21th2020 to French patients aged 12 years and older with advanced CF who were treated with elexacaftor-tezacaftor-ivacaftor. Their responses were summarized as numbers (%), and free-text items were analysed using a grounded theory approach.
Results: Of 245 patients who started elexacaftor-tezacaftor-ivacaftor in France, 101 (41%) participated. Median [IQR] age was 35 [28-41] years and duration of elexacaftor-tezacaftor-ivacaftor treatment was 4.3 [3.0-5.6] months. Patients generally reported a rapid impact on respiratory symptoms, sleep quality, general well-being and physical self-esteem, and a reduction in overall treatment burden. The majority of patients contrasted treatment burden, symptom severity, depression and a closed future marked by death or transplantation before elexacaftor-tezacaftor-ivacaftor, to renewed and unexpected physical strength, leading to greater self-confidence, autonomy and long-term planning, after treatment initiation. A small number of patients expressed concerns, mainly regarding changes in body representation and/or the fear of becoming dependent on the treatment.
Conclusion: After initiation of elexacaftor-tezacaftor-ivacaftor, CF patients with advanced disease reported rapid and positive physical, psychological and social effects, which translated into improved quality of life and the formulation of new life goals.

 Dr C Martin is at the Université de Paris, Institut Cochin, Inserm U1016, Paris, France; Respiratory Medicine and National Reference Cystic Fibrosis Reference Center, Cochin Hospital, Assistance Publique Hôpitaux de Paris (AP-HP), Paris, France; ERN-Lung CF network.