Therapies for pulmonary arterial hypertension: where are we today, where do we go tomorrow?

Pulmonary arterial hypertension (PAH) is a progressive disease characterised by remodelling of small pulmonary arteries leading to an increased pulmonary vascular resistance, right ventricular failure and death. Available treatments try to re-establish the equilibrium on three signalling pathways: the prostacyclin, the endothelin (ET)-1 and the nitric oxide. Prostanoids, such as epoprostenol or treprostinil have a vasodilator, antiproliferative and immunomodulatory effect and, despite the administration inconveniences, represent established therapies for severe cases of PAH. Recently oral prostacyclin receptor agonists have shown encouraging results. Many clinical studies targeting the vasoconstrictor ET-1 pathway with receptor antagonists like bosentan and ambrisentan have shown strong results, even more optimism coming from macitentan, the newest drug. Sildenafil and tadalafil, two phosphodiesterase type-5 inhibitors, have shown improved exercise capacity by increasing the nitric oxide level. Riociguat, acting on the same nitric oxide pathway, as a guanylatecyclase activator, has shown promising results in clinical trials and will be available soon. Long-awaited results for tyrosin-kinase inhibitor, imatinib, as an antiproliferative therapy in PAH have been disappointing, due to severe adverse events. In conclusion, although it remains a disease with severe prognosis, the past 20 years have represented a huge progress in terms of treatments for PAH with interesting opportunities for the future

Drug-induced pulmonary arterial hypertension: a recent outbreak

Pulmonary arterial hypertension (PAH) is a rare disorder characterised by progressive obliteration of the pulmonary microvasculature resulting in elevated pulmonary vascular resistance and premature death. According to the current classification PAH can be associated with exposure to certain drugs or toxins, particularly to appetite suppressant intake drugs, such as aminorex, fenfluramine derivatives and benfluorex. These drugs have been confirmed to be risk factors for PAH and were withdrawn from the market. The supposed mechanism is an increase in serotonin levels, which was demonstrated to act as a growth factor for the pulmonary artery smooth muscle cells. Amphetamines, phentermine and mazindol were less frequently used, but are considered possible risk factors, for PAH. Dasatinib, dual Src/Abl kinase inhibitor, used in the treatment of chronic myelogenous leukaemia was associated with cases of severe PAH, potentially in part reversible after dasatinib withdrawal. Recently, several studies have raised the issue of potential endothelial dysfunction that could be induced by interferon, and a few cases of PAH have been reported with interferon therapy. PAH remains a rare complication of these drugs, suggesting possible individual susceptibility, and further studies are needed to identify patients at risk of drug-induced PAH

Evaluation of Real-Life Chemoimmunotherapy Combination in Patients with Metastatic Small Cell Lung Carcinoma (SCLC): A Multicentric Case–Control Study

The current first-line standard treatment for advanced small cell lung cancer (SCLC) is a combination of chemotherapy and immunotherapy. However, few efficacy data are available in a real-life settings, including frail patients. The aim of this study is to describe the real-life efficacy of chemoimmunotherapy in an unselected SCLC population. We conducted a retrospective multicenter study, which compared two cohorts of patients with treatment-naive metastatic SCLC treated in six academic centers in the Greater Paris area. Cohort 1 included patients treated with chemotherapy between January 2017 and December 2018, and cohort 2 included patients treated with chemoimmunotherapy between January 2019 and December 2020. A total of 153 consecutive patients were included (cohort 1: n = 96; cohort 2: n = 57). Clinical characteristics were similar between the two cohorts. Overall survival (OS) was statistically higher in cohort 2 (median survival 15.47 months) than in cohort 1 (median survival 9.5 months) (p = 0.0001). OS for patients with a performance status ≥2 and for patients ≥70 years old was not statistically different between the two cohorts. Chemoimmunotherapy efficacy was better compared to chemotherapy alone in case of brain or liver metastases. In conclusion, the combination of chemoimmunotherapy in metastatic SCLC appears to provide a real-life OS benefit. Dedicated clinical trials are needed to test this strategy in patients with impaired performance status or advanced age

Tyrosine kinase inhibitors in pulmonary arterial hypertension: a double-edge sword?

New treatments for pulmonary arterial hypertension (PAH) are a crucial need. The increased proliferation, migration, and survival of pulmonary vascular cells within the pulmonary artery wall in PAH have allowed successful transposition of pathophysiological elements from oncologic researches. Next steps will require translation of these biological advances in PAH therapeutic arsenal and guidelines. This review synthesizes recent data concerning the role of receptor tyrosine kinases and their inhibitors in PAH, with implications in animal models and humans. Results of clinical trials are now accumulating to establish beneficial role of tyrosine kinase inhibitors (TKIs) in PAH and further findings are expected in the near future. Beside this curative approach, evidences of a possible TKI-induced cardiotoxicity are emerging. These safety issues raise concern about a potential amplified harmful effect in PAH, a pathology characterized by an underlying cardiac dysfunction. In addition, analyses of PAH registries shed light on a selective pulmonary vascular toxicity triggered by TKIs, especially dasatinib. These possible dual effects of the TKIs in PAH need to be taken in account for future pharmacological development of this therapeutic class in PAH

The potential for macitentan, a new dual endothelin receptor antagonist, in the treatment of pulmonary arterial hypertension

In recent years in the management of pulmonary arterial hypertension (PAH), endothelin receptor antagonists (ERAs) represent a well-established class of therapeutic agents with clear beneficial effects. Macitentan (Opsumit ® ), a dual ERA optimized for efficacy and safety, is the newest drug in the class. Macitentan presents a number of key beneficial characteristics, including increased in vivo preclinical efficacy versus existing ERAs, resulting from sustained receptor binding and physicochemical properties that allow enhanced tissue penetration. The clinical pharmacokinetics studies also indicated a low predilection of macitentan for drug–drug interactions. In the SERAPHIN trial, a phase III long-term study of PAH, macitentan significantly reduced morbidity and mortality by 45% versus placebo, providing sustained long-term improvements in exercise capacity. No association was found between changes in exercise capacity and long-term clinical outcomes, but improved cardiopulmonary hemodynamics were recorded in macitentan-treated patients irrespective of baseline background PAH therapy or World Health Organization functional class. Based on these favorable data, the US Food and Drug Administration approved the 10 mg/day dose in late 2013 and the same process has recently been concluded by the European Medicines Agency

Colony stimulating factor-1 (CSF-1) signalling is predictive of response to immune checkpoint inhibitors in advanced non-small cell lung cancer

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Increased Pericyte Coverage Mediated by Endothelial-Derived Fibroblast Growth Factor-2 and Interleukin-6 Is a Source of Smooth Muscle–Like Cells in Pulmonary Hypertension

International audienceBACKGROUND:Pericytes and their crosstalk with endothelial cells are critical for the development of a functional microvasculature and vascular remodeling. It is also known that pulmonary endothelial dysfunction is intertwined with the initiation and progression of pulmonary arterial hypertension (PAH). We hypothesized that pulmonary endothelial dysfunction, characterized by abnormal fibroblast growth factor-2 and interleukin-6 signaling, leads to abnormal microvascular pericyte coverage causing pulmonary arterial medial thickening.METHODS AND RESULTS:In human lung tissues, numbers of pericytes are substantially increased (up to 2-fold) in distal PAH pulmonary arteries compared with controls. Interestingly, human pulmonary pericytes exhibit, in vitro, an accentuated proliferative and migratory response to conditioned media from human idiopathic PAH endothelial cells compared with conditioned media from control cells. Importantly, by using an anti-fibroblast growth factor-2 neutralizing antibody, we attenuated these proliferative and migratory responses, whereas by using an anti-interleukin-6 neutralizing antibody, we decreased the migratory response without affecting the proliferative response. Furthermore, in our murine retinal angiogenesis model, both fibroblast growth factor-2 and interleukin-6 administration increased pericyte coverage. Finally, using idiopathic PAH human and NG2DsRedBAC mouse lung tissues, we demonstrated that this increased pericyte coverage contributes to pulmonary vascular remodeling as a source of smooth muscle-like cells. Furthermore, we found that transforming growth factor-β, in contrast to fibroblast growth factor-2 and interleukin-6, promotes human pulmonary pericyte differentiation into contractile smooth muscle-like cells.CONCLUSIONS:To the best of our knowledge, this is the first report of excessive pericyte coverage in distal pulmonary arteries in human PAH. We also show that this phenomenon is directly linked with pulmonary endothelial dysfunction

Dasatinib increases endothelial permeability leading to pleural effusion

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