Clinical course of mild-to-moderate idiopathic pulmonary fibrosis during therapy with pirfenidone: Results of the non-interventional study AERplus.

INTRODUCTION: Pirfenidone was the first anti-fibrotic drug approved in Europe in 2011 for the treatment of mild-to-moderate idiopathic pulmonary fibrosis. OBJECTIVES: To investigate the clinical course of mild-to-moderate idiopathic pulmonary fibrosis in pirfenidone-treated patients in a real-world setting. METHODS: The non-interventional study was conducted at 18 sites in Germany from 6/2014-12/2016. Adult patients with mild-to-moderate idiopathic pulmonary fibrosis were treated with pirfenidone (escalated from 3×1 to 3×3 capsules of 267 mg/day within 3 weeks) for 12 months. The observation period comprised 4 follow-up visits at months 3, 6, 9 and 12. Disease progression was defined as decrease of ≥10% in vital capacity or ≥15% in diffusing capacity of the lung for carbon monoxide (DLCO) and/or ≥50m in 6-minute walking distance vs. baseline, or "lack of response/progression" as reason for therapy discontinuation. RESULTS: A total of 51 patients (80.4% male, mean age 70.6 years) were included in the full analysis set. Disease progression at any visit was reported for 23 (67.6%) of 34 patients with available data. Over the course of the study, lung function parameters, physical resilience, impact of cough severity on quality of life, and the mean Gender, Age and Physiology Index (stage II) remained stable. In total, 29 patients (56.9%) experienced at least one adverse drug reaction (11 patients discontinued due to adverse drug reactions); serious adverse reactions were reported in 12 patients (23.5%). CONCLUSIONS: The results of this study are in line with the established benefit-risk profile of pirfenidone. Therefore, pirfenidone can be considered a valuable treatment option to slow disease progression in mild-to-moderate idiopathic pulmonary fibrosis. NCT02622477.

Short-term safety results from compassionate use of risdiplam in patients with spinal muscular atrophy in Germany.

BACKGROUND: The oral, selective SMN2-splicing modifier risdiplam obtained European approval in March 2021 for the treatment of patients ≥ 2 months old with a clinical diagnosis of 5q-associated spinal muscular atrophy (SMA) 1/2/3 or with 1-4 SMN2 gene copies. For the preceding 12 months, this compassionate use program (CUP) made risdiplam available to patients with SMA1/2 in Germany who could not receive any approved SMA therapy. PATIENTS AND METHODS: Patients with SMA1/2, aged ≥ 2 months at enrollment, could be included if they were not eligible for, no longer responsive to, or not able to tolerate nusinersen or not able to receive onasemnogene abeparvovec. Oral risdiplam dosing ranged from 0.2 mg/kg to 5 mg depending on age and weight. All treatment decisions were made by the attending physicians, who were required to report all adverse events (AEs). RESULTS: Between March 12, 2020 and March 30, 2021, 36 patients with SMA1 and 98 patients with SMA2 were enrolled, with 31 patients and 80 patients receiving ≥ 1 risdiplam dose, respectively. The median (range) age was 10.5 (3-52) years in the SMA1 cohort, and 26.5 (3-60) years in the SMA2 cohort. 22.2% of patients with SMA1 and 48.0% with SMA2 were treatment-naïve. Most patients were not eligible/could not continue to receive nusinersen due to scoliosis/safety risk (SMA1: 75.0%; SMA2: 96.9%), risks associated with sedation (77.8%; 63.3%), or loss of efficacy (30.6%; 12.2%). Safety data were generally in line with the safety profile of risdiplam in ongoing clinical studies. Gastrointestinal disorders were the most common AEs. For patients with SMA1, 30 AEs were reported in 13 cases with 2 serious AEs in 1 patient. For SMA2, 100 AEs were documented in 31 case reports, including 8 serious AEs in 2 patients. CONCLUSIONS: We present the first real-world safety data of risdiplam in patients with SMA in Germany. Our observations indicated no new safety signals under real-world conditions. Real-world SMA1/2 populations comprise considerable numbers of patients who are not eligible for gene therapy and cannot tolerate or have failed nusinersen treatment. This medical need may be addressed by oral risdiplam.

IL-13 Impairs Tight Junctions in Airway Epithelia.

Interleukin-13 (IL-13) drives symptoms in asthma with high levels of T-helper type 2 cells (Th2-cells). Since tight junctions (TJ) constitute the epithelial diffusion barrier, we investigated the effect of IL-13 on TJ in human tracheal epithelial cells. We observed that IL-13 increases paracellular permeability, changes claudin expression pattern and induces intracellular aggregation of the TJ proteins zonlua occludens protein 1, as well as claudins. Furthermore, IL-13 treatment increases expression of ubiquitin conjugating E2 enzyme UBE2Z. Co-localization and proximity ligation assays further showed that ubiquitin and the proteasomal marker PSMA5 co-localize with TJ proteins in IL-13 treated cells, showing that TJ proteins are ubiquitinated following IL-13 exposure. UBE2Z upregulation occurs within the first day after IL-13 exposure. Proteasomal aggregation of ubiquitinated TJ proteins starts three days after IL-13 exposure and transepithelial electrical resistance (TEER) decrease follows the time course of TJ-protein aggregation. Inhibition of JAK/STAT signaling abolishes IL-13 induced effects. Our data suggest that that IL-13 induces ubiquitination and proteasomal aggregation of TJ proteins via JAK/STAT dependent expression of UBE2Z, resulting in opening of TJs. This may contribute to barrier disturbances in pulmonary epithelia and lung damage of patients with inflammatory lung diseases.

Inflammation-induced upregulation of P2X4 expression augments mucin secretion in airway epithelia.

Mucus clearance provides an essential innate defense mechanism to keep the airways and lungs free of particles and pathogens. Baseline and stimulated mucin secretion from secretory airway epithelial cells need to be tightly regulated to prevent mucus hypersecretion and mucus plugging of the airways. It is well established that extracellular ATP is a potent stimulus for regulated mucus secretion. Previous studies revealed that ATP acts via metabotropic P2Y2 purinoreceptors on goblet cells. Extracellular ATP, however, is also a potent agonist for ionotropic P2X purinoreceptors. Expression of several P2X isoforms has been reported in airways, but cell type-specific expression and the function thereof remained elusive. With this study, we now provide evidence that P2X4 is the predominant P2X isoform expressed in secretory airway epithelial cells. After IL-13 treatment of either human primary tracheal epithelial cells or mice, P2X4 expression is upregulated in vitro and in vivo under conditions of chronic inflammation, mucous metaplasia, and hyperplasia. Upregulation of P2X4 is strongest in MUC5AC-positive goblet cells. Moreover, activation of P2X4 by extracellular ATP augments intracellular Ca2+ signals and mucin secretion, whereas Ca2+ signals and mucin secretion are dampened by inhibition of P2X4 receptors. These data provide new insights into the purinergic regulation of mucin secretion and add to the emerging picture that P2X receptors modulate exocytosis of large secretory organelles and secretion of macromolecular vesicle cargo.

Vesicular control of fusion pore expansion.

Exocytic post-fusion events play an important role determining the composition and quantity of cellular secretion. In particular, Ca(2+)-dependent regulation of fusion pore dilation/closure is a key regulator for fine-tuning vesicle content secretion. This requires a tight temporal and spatial integration of vesicle fusion with the PM, Ca(2+) signals and translation of the Ca(2+) signal into fusion pore dilation via auxiliary factors. Yet, it is still mostly elusive how this is achieved in slow and non-excitable secretory cells, where initial Ca(2+) signals triggering fusions will abate before onset of the post-fusion phase. New results suggest, that the vesicles themselves provide the necessary itinerary to sense and link vesicle fusion to generation of local Ca(2+) signals and fusion pore expansion.

Synaptotagmin-7 links fusion-activated Ca²âº entry and fusion pore dilation.

Ca(2+)-dependent regulation of fusion pore dilation and closure is a key mechanism determining the output of cellular secretion. We have recently described 'fusion-activated' Ca(2+) entry (FACE) following exocytosis of lamellar bodies in alveolar type II cells. FACE regulates fusion pore expansion and facilitates secretion. However, the mechanisms linking this locally restricted Ca(2+) signal and fusion pore expansion were still elusive. Here, we demonstrate that synaptotagmin-7 (Syt7) is expressed on lamellar bodies and links FACE and fusion pore dilation. We directly assessed dynamic changes in fusion pore diameters by analysing diffusion of fluorophores across fusion pores. Expressing wild-type Syt7 or a mutant Syt7 with impaired Ca(2+)-binding to the C2 domains revealed that binding of Ca(2+) to the C2A domain facilitates FACE-induced pore dilation, probably by inhibiting translocation of complexin-2 to fused vesicles. However, the C2A domain hampered Ca(2+)-dependent exocytosis of lamellar bodies. These findings support the hypothesis that Syt7 modulates fusion pore expansion in large secretory organelles and extend our picture that lamellar bodies contain the necessary molecular inventory to facilitate secretion during the exocytic post-fusion phase. Moreover, regulating Syt7 levels on lamellar bodies appears to be essential in order that exocytosis is not impeded during the pre-fusion phase.