Drug development for cystic fibrosis

Cystic fibrosis in Europe: improved lung function and longevity - reasons for cautious optimism, but challenges remain

BACKGROUND

Prognosis and disease severity in cystic fibrosis (CF) are linked to declining lung function. To characterise lung function by the number of adults in countries with different levels of Gross National Income (GNI), data from the European Cystic Fibrosis Society Patient Registry were utilised.

METHODS

Annual data including age, forced expiratory volume in 1 s (FEV1), anthropometry, genotype, respiratory cultures and CF-related diabetes (CFRD) were retrieved between 2011 and 2021. All countries were stratified into GNI per capita to reflect differences within Europe.

RESULTS

A consistent improvement in FEV1 % pred and survival was observed among the 47 621 people with CF (pwCF), including subjects with chronic Pseudomonas aeruginosa infection, CFRD and/or undernutrition. Mean values of FEV1 % pred changed from 85% to 94.2% for children and from 63.6% to 74.7% for adults. FEV1 % pred further increased among those carrying the F508del mutation in 2021, when elexacaftor/tezacaftor/ivacaftor was available. The number of adult pwCF increased from 13 312 in 2011 to 21 168 in 2021, showing a 60% increase. PwCF living in European lower income countries did not demonstrate a significant annual increase in FEV1 % pred or in the number of adults.

CONCLUSION

This pan-European analysis demonstrates a consistent improvement in FEV1 % pred, number of adult pwCF and survival over the last decade only in European higher and middle income countries. Urgent action is needed in the lower income countries where such improvement was not observed. The notable improvement observed in pwCF carrying the F508del mutation emphasises the need to develop treatments for all CF mutations.

Traits, trends and hits of orphan drug designations in cystic fibrosis

BACKGROUND

In the United States (US) and in Europe, cystic fibrosis (CF) qualifies as a rare disease, thus positioning the field to benefit from regulatory incentives provided by orphan drug designation (ODD) to boost pharmaceutical research and development. In this study, we analyzed the pool of products for the treatment of CF that received such incentives from the US Food and Drug Administration (FDA) and/or the European Medicines Agency (EMA) over the past two decades. We describe the characteristics and trends in ODDs over time and explore factors that might be determinants of successful drug development.

METHODS

We collected the products that received the ODD from the registries of the FDA and the EMA from 2000 to 2021, characterizing their nature, development stage, and type of sponsor. We categorized the study drugs according to the therapeutic target addressed and described trends of drug development over the study period. A logistic regression analysis was done to assess how ODD characteristics were associated with the approval for market authorization.

RESULTS

From 2000-2021, 107 ODDs were collectively granted by the FDA and the EMA for products developed for the treatment of CF. Although the trends of the number of ODDs granted remained stable over time, those targeting the CF basic protein defect increased from 6 out of 54 (11.1%) in the first half of the study period up to 20 out of 54 (37.7%) in the second half, while those treating symptoms decreased from 48/54 (88.9%) to 33/53 (62.3%). Overall, 10 products obtained marketing approval: 7 in both the US and Europe, 3 only in Europe. All the approved ODDs were chemical products for chronic use. No statistically significant difference was found across the examinated variables, but we observed possible drivers of successful drug development for ODDs targeting CFTR, as well as for those with active substances previously marketed, and for those developed by large companies and companies with experience in developing orphan drugs. By contrast, our findings suggest that financial issues most hamper the development of ODDs sponsored by small-medium enterprises.

CONCLUSIONS

Although ODDs for treating infection and other CF sequelae accounted for the majority, we observed a shift of ODDs toward mechanism-based products over the study period. In line with other rare diseases, we found that approximately 1/10 ODDs for CF reached the status of marketing approval. Advances in disease genetics paved the way for a shift in CF drug development; however, we described how the convergence of pharmaceutical technology, the financial environment, and the regulatory ecosystem played a crucial role in successful marketing authorization in CF.

ABC transporters: human disease and pharmacotherapeutic potential

Adenosine triphosphate (ATP)-binding cassette (ABC) transporters are a 48-member superfamily of membrane proteins that actively transport a variety of biological substrates across lipid membranes. Their functional diversity defines an expansive involvement in myriad aspects of human biology. At least 21 ABC transporters underlie rare monogenic disorders, with even more implicated in the predisposition to and symptomology of common and complex diseases. Such broad (patho)physiological relevance places this class of proteins at the intersection of disease causation and therapeutic potential, underlining them as promising targets for drug discovery, as exemplified by the transformative CFTR (ABCC7) modulator therapies for cystic fibrosis. This review will explore the growing relevance of ABC transporters to human disease and their potential as small-molecule drug targets.

Inflammation and Infection in Cystic Fibrosis: Update for the Clinician

Inflammation and infection play an important role in the pathophysiology of cystic fibrosis, and they are significant causes of morbidity and mortality in CF. The presence of thick mucus in the CF airways predisposes to local hypoxia and promotes infection and inflammation. A vicious cycle of airway obstruction, inflammation, and infection is of critical importance for the progression of the disease, and new data elucidate the different factors that influence it. Recent research has been focused on improving infection and inflammation in addition to correcting the basic gene defect. This review aims to summarize important advances in infection and inflammation as well as the effect of new treatments modulating the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) protein. New approaches to target infection and inflammation are being studied, including gallium, nitric oxide, and phage therapy for infection, along with retinoids and neutrophil elastase inhibitors for inflammation.

Novel treatments for autism spectrum disorder based on genomics and systems biology

BACKGROUND

Autism spectrum disorder (ASD) is a highly heterogeneous neurodevelopmental disorder with a complex underlying genetic architecture. There are currently no known pharmacologic treatments for the core ASD symptoms of social deficits and restricted/ repetitive behavior. However, there are dozens of clinical trials currently underway that are testing the impact of novel and existing agents on core and associated symptoms in ASD.

METHODS

We present a narrative synthesis of the historical and contemporary challenges to drug discovery in ASD. We then provide an overview of novel treatments currently under investigation from a genomics and systems biology perspective.

RESULTS

Data driven network and cluster analyses suggest alterations in transcriptional regulation, chromatin remodelling, synaptic transmission, neuropeptide signalling, and/or immunological mechanisms may contribute to or underlie the development of ASD. Agents and upcoming trials targeting each of the above listed systems are reviewed.

CONCLUSION

Identifying effective pharmacologic treatments for the core and associated symptom domains in ASD will require further collaboration and innovation in the areas of outcome measurement, biomarker research, and genomics, as well as systematic efforts to identify and treat subgroups of individuals with ASD who may be differentially responsive to specific treatments.