Two Unanticipated Pregnancies While on Cystic Fibrosis Gene-Specific Drug Therapy

Use of CFTR modulators in special populations, part 1: Pregnancy and lactation

Safety and efficacy data regarding cystic fibrosis transmembrane conductance regulator (CFTR) modulator use in the setting of pregnancy or breastfeeding remains lacking due to exclusion from key trials and lack of multicenter prospective and retrospective studies in the post-CFTR modulator era. A scoping review of English articles from the period of January 1, 2012, to July 31, 2023, was conducted utilizing PubMed and EmBase databases with the following terms: "special population (pregnancy, lactation, breastfeeding)" AND "ivacaftor OR lumacaftor OR tezacaftor OR elexacaftor"; "cystic fibrosis transmembrane conductance regulator" AND "off label drug use." Search results were reviewed by title and abstract for duplications and relevance. Relative to pregnancy or breastfeeding, a total of 18 publications were included for review. Majority of case reports and surveys concluded maternal and infant health were preserved throughout gestation. Likewise, breastfeeding infant case reports show possible changes in liver function and lens opacities, though risk may be increased with both in-utero and breastfeeding exposure. Ivacaftor (IVA) and lumacaftor (LUM) concentrations in fetal cord blood and maternal blood were found to be equivalent. Yet, low concentrations of IVA and LUM were detectable in breastmilk and infant plasma. Current safety data surrounding CFTR modulator use in the setting of pregnancy and lactation is relatively reassuring; however, long-term safety remains unclear, necessitating ongoing observation, and reporting by care teams. As such, treatment decisions should be individualized and coproduced.

Effects of modulator therapies on endocrine complications in adults with cystic fibrosis: a narrative review

Cystic fibrosis is a monogenic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) protein, which transports chloride ions in secretory organs. Modulator therapies are small molecules that correct CFTR dysfunction and can lead to a wide range of benefits for both pulmonary and extrapulmonary complications of cystic fibrosis. With advancements in airway, antimicrobial and nutritional therapies and now introduction of modulator therapies, most people living with cystic fibrosis in Australia are now adults. For adults with cystic fibrosis, endocrine manifestations such as cystic fibrosis-related diabetes, metabolic bone disease, and reproductive health are becoming increasingly important, and emerging evidence on the endocrine effects of CFTR modulator therapies is promising and is shifting paradigms in our understanding and management of these conditions. The management of cystic fibrosis-related diabetes will likely need to pivot for high responders to modulator therapy with dietary adaptions and potential use of medications traditionally reserved for adults with type 2 diabetes, but evidence to support changing clinical care needs is currently lacking. Increased attention to diabetes-related complications screening will also be required. Increased exercise capacity due to improved lung function, nutrition and potentially direct modulator effect may have a positive impact on cystic fibrosis-related bone disease, but supporting evidence to date is limited. Fertility can improve in women with cystic fibrosis taking modulator therapy. This has important implications for pregnancy and lactation, but evidence is lacking to guide pre-conception and antenatal management. Provision of multidisciplinary clinical care remains ever-important to ensure the emergence of endocrine and metabolic complications are optimised in adults with cystic fibrosis.

Pregnancy in Cystic Fibrosis-Past, Present, and Future

The introduction of mutation-specific therapy led to a revolution in cystic fibrosis (CF) care. These advances in CF therapies have changed the disease profile from a severe incurable disease with limited survival to a treatable disease with improved quality of life and survival into adulthood. CF patients are now able to plan their future, including marriage and parenthood. Side by side with the optimism, new issues and concerns are arising, including fertility and preparation for pregnancy, maternal and fetal care during pregnancy, and post-partum care. While cystic fibrosis transmembrane regulator (CFTR) modulators show promising results for improving CF lung disease, data on their safety in pregnancy are still limited. We performed a literature review on pregnancy in CF from the past, with the first described pregnancy in 1960, through the current fascinating changes in the era of CFTR modulators, to ongoing studies and future directions. Current advances in knowledge give hope for improved outcomes of pregnancy, towards the best possible prognosis for the mother and for the baby.

Review of CFTR modulators 2020

Cystic fibrosis transmembrane conductance regulator (CFTR) modulators are small molecules that directly impact the CFTR protein, improving the function of the CFTR chloride and bicarbonate channel. Beginning in 2012 with the Food and Drug Administration approval of the first CFTR modulator, ivacaftor, this class of medications has had largely positive effects on many outcomes in people with cystic fibrosis (PwCF), including lung function, growth, and other clinical parameters. There have been continued exciting developments in the current research on CFTR modulators, expanding beyond original studies. This first part of a three-part cystic fibrosis (CF) year in review 2020 will focus on research on CFTR modulators. In addition to reviewing new clinical insights, we describe work done on novel outcomes, adverse effects, issues related to cost, and next steps for clinical trials. The review focuses on articles from Pediatric Pulmonology published in 2020, but it includes articles from other journals that are of particular interest to clinicians. New developments in CF research continue to be brought forth to the CF community, deepening the understanding of this disease and improving clinical care.

In vitro functional rescue by ivacaftor of an ABCB11 variant involved in PFIC2 and intrahepatic cholestasis of pregnancy

Background

ABCB11 variations are responsible for a spectrum of rare liver diseases, including progressive familial intrahepatic cholestasis type 2 (PFIC2) and intrahepatic cholestasis of pregnancy (ICP). Current medical treatment of these conditions mostly relies on ursodeoxycholic acid with limited efficacy. We report on the in vitro study of the p.A257V missense variant of ABCB11 identified in a PFIC2 patient and in her mother who experienced ICP.

Results

The Ala257 residue is located outside the ATP-binding site of ABCB11. We show that the p.A257V variant of ABCB11 is correctly expressed at the canalicular membrane of HepG2 cells but that its function significantly decreased when studied in MDCK cells. This functional defect can be fully rescued by Ivacaftor.

Conclusion

Ivacaftor could be considered as a new pharmacological tool able to respond to an unmet medical need for patients with ICP and PFIC2 due to ABCB11 variations affecting ABCB11 function, even when the residue involved is not located in an ATP-binding site of ABCB11.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13023-021-02125-4.

Fertility, Pregnancy and Lactation Considerations for Women with CF in the CFTR Modulator Era

Cystic fibrosis (CF) is an autosomal recessive genetic disorder impacting approximately 80,000 people of all races and ethnicities world-wide. CF is caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene which encodes a protein of the same name. Protein dysfunction results in abnormal chloride and bicarbonate transport in mucus membranes, including those in the respiratory, gastrointestinal and reproductive tracts. Abnormal anion transport causes viscous secretions at the site of involvement. The majority of people with CF succumb to respiratory failure following recurrent cycles of infection and inflammation in the airways. Historically, providers treated the signs and symptoms of CF, but since 2012, have been able to impact the basic defect for the subset of people with CF who have mutations that respond to the new class of drugs, CFTR protein modulators. With the improved health and longevity afforded by CFTR modulators, more women are interested in parenthood and are becoming pregnant. Furthermore, this class of drugs likely increases fertility in women with CF. However, the safety of CFTR modulators in pregnancy and lactation is only beginning to be established. We summarize available data on the impact of CFTR modulators on fertility, pregnancy and lactation in women with CF.

Elexacafator/tezacaftor/ivacaftor resolves subfertility in females with CF: A two center case series

Infertility and subfertility are commonly faced by females with cystic fibrosis (FwCF) and resulting in decreased contraceptive use and increased utilization of reproductive technologies. Elexacaftor-tezacaftor-ivacaftor (ETI) is a CFTR modulator that affects common causes of subfertility. Two CF centers conducted a retrospective chart review on females with CF who were receiving ETI and became pregnant. We analyzed obstetrical-gynecological history, genotype, and clinical response to ETI therapy. Fourteen FwCF on ETI became pregnant. Half (7) of the FwCFs were previously attempting to conceive, but only three were using contraceptives. Four FwCF had a history of infertility; two were reconsidering use of reproductive technologies (IUI). Patients achieved conception at mean 8 weeks after initiating ETI. ETI may lessen CF-associated factors that affect fertility; however, its exact mechanism is unknown. This warrants counseling on contraceptive use and family planning prior to initiation of therapy and at routine intervals while utilizing ETI.

Maternal and fetal outcomes following elexacaftor-tezacaftor-ivacaftor use during pregnancy and lactation

BACKGROUND

With the improved health afforded by cystic fibrosis transmembrane conductance regulator (CFTR) modulators, pregnancy rates are increasing in women with CF. In animal reproductive models, the three components of elexacaftor-tezacaftor-ivacaftor (ETI) did not cause teratogenicity at normal human doses. Although the limited human data available in the literature for previously approved modulators did not suggest cause for concern, there is currently no data in the literature regarding use of 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 fetal 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-center prospective study is needed to assess impact of use of ETI in pregnancy.

Challenges in the use of highly effective modulator treatment for cystic fibrosis

The last decade has seen development of oral, small molecule therapies that address the basic cystic fibrosis transmembrane conductance regulator (CFTR) protein defect. Highly effective modulator treatment (HEMT) that is efficacious for a large majority of people living with cystic fibrosis (CF) promises to change the landscape of this chronic life-limiting disease. Some people living with CF have a CFTR genotype that renders them eligible for HEMT, but also have comorbidities that excluded them from the original Phase III clinical trials that led to US Food and Drug Administration approval. The purpose of this review is to address the use of HEMT in challenging situations, including initiation for those with advanced CF lung disease, and use after solid organ transplant, during pregnancy, and for individuals with CFTR-related disorders without a definitive diagnosis of CF.

CFTR Modulators: Impact on Fertility, Pregnancy, and Lactation in Women with Cystic Fibrosis

Cystic fibrosis (CF) is a life-shortening genetic disorder caused by mutations in the cystic fibrosis transmembrane conductance regulator (CFTR) gene. These mutations lead to abnormal ion transport in mucous membranes throughout the body, including in the respiratory and gastrointestinal and reproductive tracts. Improvements in care and therapy have led to substantial increases in the quantity and quality of life for those with CF. Consequently, women with CF are increasingly interested in having families. Although pregnancy was once discouraged for women with CF, at this point, even women with moderately severe lung disease can successfully navigate pregnancy. With the recent approval of a triple combination CFTR modulator therapy that improves lung function, nutritional status, and quality of life for people with a single copy of the most common CFTR mutation, it is expected that the number of women with CF who choose to become pregnant will continue to increase. Although animal reproduction models show no alarming signals for use during pregnancy at normal human doses, there is a paucity of human safety data in pregnancy and lactation. This review summarizes what is currently known about the impact of use of CFTR modulators on fertility, pregnancy, and lactation in women with CF.