Sequential treatment with sildenafil and riociguat in patients with persistent or inoperable chronic thromboembolic pulmonary hypertension improves functional class and pulmonary hemodynamics

Efficacy and safety of riociguat replacing PDE-5is for patients with pulmonary arterial hypertension: A systematic review and meta-analysis

Introduction: Pulmonary arterial hypertension (PAH) is a rare and progressive disease. Some patients treated with phosphodiesterase type 5 inhibitors (PDE-5is) fail to reach treatment goals. As a novel soluble guanylate cyclase agonist, riociguat acts on the same pathway as PDE-5is but functions via different mechanisms. Whether riociguat is more effective and safer than PDE-5is is ambiguous. We aimed to evaluate the efficacy and safety of switching from PDE-5is to riociguat among these patients. Methods: Original published articles were retrieved from PubMed/Medline, Embase, Web of Science, Open Grey and Google Scholar. Studies that assessed the World Health Organization functional class (WHO-FC), 6-min walking distance (6MWD), pulmonary vascular resistance (PVR), mean pulmonary arterial pressure (mPAP), cardiac index (CI) and N-terminal pro-B-type natriuretic peptide (NT-proBNP) were collected. Adverse events after switching were evaluated. Results: Ten published studies were included. Compared to PDE-5is, riociguat significantly increased the 6MWD by 26.45 m weighted mean difference (WMD) = 26.45 m, 95% confidence intervals (CIs): 9.70-43.2 m, p = 0.002) and improved mPAP (WMD = -3.53, 95% CIs: -5.62-1.44 mmHg, p = 0.0009), PVR (WMD = -130.24 dyn·s·cm^-5, 95% CI -187.43-73.05, p < 0.0001), CIs (WMD = 0.36 L/min·cm^-2, 95% CIs: 0.25-0.47, p < 0.00001) and WHO-FC (OR = 0.11, 95% CIs: 0.08-0.16, p < 0.0001) but not NT-proBNP. In addition, we did not observe the most common side effects during the replacement of riociguat for PDE-5is. Conclusions: PAH patients benefit from PDE-5is compared to riociguat, including in hemodynamic parameters, 6MWD, WHO-FC and biomarkers.

Riociguat and the right ventricle in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension

Pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) are progressive diseases that can lead to right heart failure and death. Right ventricular dysfunction, hypertrophy and maladaptive remodelling are consequences of increased right ventricular (RV) afterload in PAH and CTEPH and are indicative of long-term outcomes. Because RV failure is the main cause of morbidity and mortality in PAH and CTEPH, successful treatments should lead to improvements in RV parameters. Riociguat is a soluble guanylate cyclase stimulator approved for the treatment of PAH and inoperable or persistent/recurrent CTEPH after pulmonary endarterectomy. This review examines the current evidence showing the effect of riociguat on the right ventricle, with particular focus on remodelling, function and structural parameters in preclinical models and patients with PAH or CTEPH.

A Comprehensive Assessment of Right Ventricular Function in Chronic Thromboembolic Pulmonary Hypertension

While chronic thromboembolic pulmonary hypertension (CTEPH) results from macroscopic and microscopic obstruction of the pulmonary vascular bed, the function of the right ventricle (RV) and increased RV afterload are the main determinants of its symptoms and prognosis. In this review, we assess RV function in patients diagnosed with CTEPH with a focus on the contributions of RV afterload and dysfunction to the pathogenesis of this disease. We will also discuss changes in RV function and geometry in response to treatment, including medical therapy, pulmonary endarterectomy, and balloon pulmonary angioplasty.

Safety and Feasibility of Riociguat Therapy for the Treatment of Chronic Pulmonary Arterial Hypertension in Infancy

The effects of riociguat, an oral-soluble guanylate-cyclase stimulator, were studied in 10 infants with chronic pulmonary arterial hypertension. Respiratory status (n = 8/10), right heart dilation (n = 7/10), function (n = 9/10), and chronic pulmonary arterial hypertension (n = 8/10) improved. Median decrement in systolic (12 [4, 14]), diastolic (14 [7, 20]), and mean arterial (14 [10, 17]) pressures were noted; no critical hypotension or hypoxemia occurred.

Optimization of specific therapy for pulmonary hypertension: the possibilities of riociguat

Pulmonary hypertension (PH) is a severe and often rapidly progressive disease with fatal outcome. Endothelial dysfunction in PH is associated with decreased nitric oxide production. After reviewing the mechanisms of action and the evidence base for specific therapy with phosphodiesterase 5 inhibitors (PDE-5) and soluble guanylate cyclase stimulators, a reseach review on switching from PDE-5 to riociguat is conducted. A potential advantage of riociguat is its independence from endogenous nitric oxide and from the other (besides PDE-5) isoenzymes of phosphodiesterases. The favorable efficacy profile of sildenafil has been proven for the main forms of pulmonary arterial hypertension, of riociguat for the main forms of pulmonary arterial hypertension and chronic thromboembolic PH. The clinical efficacy of replacing PDE-5 with riociguat has been demonstrated in uncontrolled trials and in the randomized controlled study REPLACE. The possibility of therapy optimization by switching from IFDE-5 to riociguat is fixed in the Russian (class and level of evidence B-3) and Eurasian (class and level of evidence IIb-B) clinical guidelines, as well as in the materials of the Cologne Expert Consensus. An additional argument for switching is the lower cost as compared to combination therapy in the Russian Federation. According to the Russian and Eurasian guidelines for PH and the Russian instructions for the use of riociguat, the drug should be taken at least 24 hours after sildenafil discontinuation.

Chronic thromboembolic pulmonary hypertension: a review

Chronic thromboembolic pulmonary hypertension (CTEPH) is a unique form of pulmonary hypertension resulting from obstruction of the pulmonary artery by fibrotic thromboembolic material, usually initiated by recurrent or incomplete resolution of pulmonary embolism. This distinct form of pulmonary hypertension is classified under Group 4 of the World Health Organization classification. Further investigations are usually initiated, with transthoracic echocardiography followed by right heart catheterisation and pulmonary angiography as the gold standard. Definitive treatment is usually in the form of surgical pulmonary endarterectomy. Inoperable CTEPH is medically treated with pharmacological agents such as phosphodiesterase Type 5 inhibitors, endothelin receptor antagonists, soluble guanylate cyclase stimulators and prostacyclin. Recent developments have made balloon pulmonary angioplasty a viable option as well.

Oxidative cross-dehydrogenative coupling (CDC) via C(sp2)-H bond functionalization: tert-butyl peroxybenzoate (TBPB)-promoted regioselective direct C-3 acylation/benzoylation of 2H-indazoles with aldehydes/benzyl alcohols/styrenes

An efficient, cost-effective, transition-metal-free, oxidative C_(sp²)–H/C_(sp²)–H cross-dehydrogenative coupling via a C_(sp²)–H bond functionalization protocol for the regioselective direct C-3 acylation/benzoylation of substituted 2H-Indazoles 1a–m with substituted aldehydes 2a–q/benzyl alcohols 5a–e/styrenes 6a–e is reported. The operationally simple protocol proceeds in the presence of tert-butyl peroxybenzoate (TBPB) as an oxidant in chlorobenzene (PhCl) as a solvent at 110 °C for 24 h under an inert atmosphere, which furnished a diverse variety of substituted 3-(acyl/benzoyl)-2H-indazoles 3a–q/4a–l in up to 87% yields. The reaction involves a free-radical mechanism and proceeds via the addition of an in situ generated acyl radical (from aldehydes/benzyl alcohols/styrenes) on 2H-indazoles. The functional group tolerance, broad substrate scope, control/competitive experiments and gram-scale synthesis and its application to the synthesis of anti-inflammatory agent 11 and novel indazole-fused diazepine 13 further signify the versatile nature of the developed methodology.

An efficient transition-metal-free oxidative C_(sp²)–H/C_(sp²)–H cross-dehydrogenative coupling via C_(sp²)–H bond functionalization for regioselective C-3 acylation/benzoylation of 2H-indazoles with aldehydes/benzyl alcohols/styrenes is reported.

Characteristics and outcomes of patients with chronic thromboembolic pulmonary hypertension in the era of modern therapeutic approaches: data from the Polish multicenter registry (BNP-PL)

Background:

Significant achievements in the treatment of chronic thromboembolic pulmonary hypertension (CTEPH) have provided effective therapeutic options for most patients. However, the true impact of the changed landscape of CTEPH therapies on patients’ management and outcomes is poorly known. We aimed to characterize the incidence, clinical characteristics, and outcomes of CTEPH patients in the modern era of CTEPH therapies.

Methods:

We analyzed the data of CTEPH adults enrolled in the prospective multicenter registry.

Results:

We enrolled 516 patients aged 63.8 ± 15.4 years. The incidence rate of CTEPH was 3.96 per million adults per year. The group was burdened with several comorbidities. New oral anticoagulants (n = 301; 58.3%) were preferred over vitamin K antagonists (n = 159; 30.8%). Pulmonary endarterectomy (PEA) was performed in 120 (23.3%) patients and balloon pulmonary angioplasty (BPA) in 258 (50%) patients. PEA was pretreated with targeted pharmacotherapy in 19 (15.8%) patients, and BPA in 124 (48.1%) patients. Persistent CTEPH was present in 46% of PEA patients and in 65% of patients after completion of BPA. Persistent CTEPH after PEA was treated with targeted pharmacotherapy in 72% and with BPA in 27.7% of patients. At a mean time period of 14.3 ± 5.8 months, 26 patients had died. The use of PEA or BPA was associated with better survival than the use of solely medical treatment.

Conclusions:

The modern population of CTEPH patients comprises mostly elderly people significantly burdened with comorbid conditions. This calls for treatment decisions that are tailored individually for every patient. The combination of two or three methods is currently a frequent approach in the treatment of CTEPH.

Clinical Trial Registration:

clinicaltrials.gov/ct2/show/NCT03959748

[The achievements of the modern specific therapy of pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension: focus on the stimulator of soluble guanylate cyclase riociguat]

Currently, treatment of pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH) is focused on three signaling pathways: the NO pathway, the endothelin pathway, and the prostacyclin pathway. Riociguat is the only representative of stimulators of the soluble guanylate cyclase (sGC) class that is approved for the treatment of PAH and inoperable and persistent/recurrent CTEPH. The review presents data from clinical trials showing a positive effect of riociguat on the functional and hemodynamic profile of patients with PAH and CTEPH. In recent years there has been much discussion about the possibility of optimizing therapy by switching to drugs that affect a single pathogenesis target. Thus, sGC stimulants have obvious advantages over phosphodiesterase type 5 (PDE-5) inhibitors, including the ability of riociguat to exert pharmacological effects (due to a NO-independent mechanism of action) even in conditions of reduced NO production. Switching from PDE-5 to riociguat may be safe and appropriate, according to clinical trials presented in the review. In accordance with the guidelines for the diagnosis and treatment of pulmonary hypertension of the Eurasian Association of cardiologists from 2019, this strategy is approved when PDE5 therapy is ineffective in patients with PAH FC III (WHO).

Treatment of chronic thromboembolic pulmonary hypertension in a multidisciplinary team

Background:

Chronic thromboembolic pulmonary hypertension (CTEPH) may be treated with pulmonary endarterectomy (PEA), balloon pulmonary angioplasty (BPA) and medical therapy (MT). Assessment in a multidisciplinary team of experts (CTEPH team) is currently recommended for treatment decision making. The aim of the present study was to report the effects of such an interdisciplinary concept.

Methods and results:

A total of 160 patients were consulted by the CTEPH team between December 2015 and September 2018. Patient baseline characteristics, CTEPH team decisions and implementation rates of diagnostic and therapeutic procedures were analysed. Change in World Health Organization (WHO) functional class and survival rates were evaluated by treatment strategy. A total of 51 (32%) patients were assessed as operable and 109 (68%) were deemed inoperable. Thirty-one (61% of operable patients) underwent PEA. Patients treated with PEA, BPA(+MT) and MT alone were 50.9 ± 14.7, 62.9 ± 15.1 and 68.9 ± 12.7 years old, respectively. At the follow-up, PEA patients had the highest WHO functional class improvement. Patients treated with BPA(+MT) had significantly better survival than PEA (p = 0.04) and MT patients (p = 0.04; 2-year survival of 92%, 79% and 79%, respectively).

Conclusions:

The CTEPH team ensures that necessary diagnostic procedures are performed. A relatively low proportion of patients was assessed by the CTEPH team as operable and underwent surgery, which in survivors resulted in the best functional improvement. Although patients undergoing BPA(+MT) were older than patients treated with PEA, their survival was better than patients subjected to PEA or MT alone.

The reviews of this paper are available via the supplemental material section.

Bu4NI-catalyzed, oxidative C(sp2)–C(sp3) cross dehydrogenative coupling for the regioselective direct C-3 benzylation of 2H-indazoles

A Bu₄NI-catalyzed, DTBP-promoted, regioselective C_(sp2)–C_(sp3) cross dehydrogenative coupling (CDC) protocol for the direct C-3 benzylation of 2H-indazoles is reported.

Chronic thromboembolic pulmonary hypertension (CTEPH): what do we know about it? A comprehensive review of the literature

: Chronic thromboembolic disease (CTED), especially when associated with pulmonary hypertension (CTEPH), is a fearsome and under-diagnosed but potentially curable complication of pulmonary embolism, thanks to recent therapeutic options. Aspecific symptoms and signs make its diagnosis challenging, requiring clinicians to be ready to suspect its presence in patients with dyspnea of unknown origin or persistent symptoms after acute pulmonary embolism. The aim of this review is to provide an update to the general practitioner or the specialist physician on the state of the art regarding the epidemiology, pathophysiology and clinical management of chronic thromboembolic syndromes.

Long-term clinical value and outcome of riociguat in chronic thromboembolic pulmonary hypertension

Background

To improve clinical outcome, patients with inoperable and residual chronic thromboembolic pulmonary hypertension (CTEPH) can be treated with riociguat. The aim of this study is to explore long-term outcomes and to compare our 'real world' data with previous research.

Methods

We included all consecutive patients with technical inoperable and residual CTEPH, in whom riociguat therapy was initiated from January 2014 onwards, with patients followed till January 2019. Survival, clinical worsening (CW), functional class (FC), N-terminal pro brain natriuretic peptide (NT-proBNP) and 6-minute walking distance (6MWD) were described yearly after riociguat initiation.

Results

Thirty-six patients (50% female, mean age 64.9 ± 12.1 years, 54% WHO FC III/IV and 6MWD 337 ± 138 m could be included, with a mean follow-up of 2.3 ± 1.2 years. Survival and CW-free survival three years after initiation of riociguat were 94% and 78%, respectively. The 6MWD per 10 m at baseline was a significant predictor (HR 0.90 [0.83-0.97], p = 0.009) for CW. At three years follow-up the WHO FC and 6MWD improved and NT-proBNP decreased compared to baseline.

Conclusion

Our study confirms that riociguat is an effective treatment in patients with technical inoperable and residual CTEPH at long-term follow-up. Although our results are consistent with previous studies, more 'real world' research is necessary to confirm long-term results.

EXPRESS: Switching to riociguat: A potential treatment strategy for the management of CTEPH and PAH

Currently, five classes of drug are approved for the treatment of pulmonary arterial hypertension (PAH): phosphodiesterase 5 inhibitors (PDE5i); endothelin receptor antagonists; prostacyclin analogs; the IP receptor agonist selexipag; and the soluble guanylate cyclase (sGC) stimulator riociguat. For patients with inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH), riociguat is currently the only approved pharmacotherapy. Despite the development of evidence-based guidelines on appropriate use of specific drugs, in clinical practice patients are often prescribed PAH-targeted therapies off label or at inadequate doses.

PDE5i are the most often prescribed class of drugs as initial therapy, either alone or in combination with other drug classes. However, a proportion of patients receiving PAH therapies do not reach or maintain treatment goals. As PDE5i and riociguat target different molecules in the nitric oxide-sGC-cyclic guanosine monophosphate (NO-sGC-cGMP) signaling pathway, for patients with PAH without an initial or sustained response to PDE5i, there is a biological rationale for switching to riociguat. However, robust data from randomized controlled trials on the safety and efficacy of switching are lacking, as is formal guidance for clinicians. Here we review studies of sequential combination therapy, and trial data and case studies that have investigated switching between PAH-approved therapies, particularly from PDE5i to riociguat in patients with PAH with an insufficient response to PDE5i, and in patients with CTEPH who were receiving off-label treatment. These studies summarize the current evidence and practical real-life experience on the concept of switching treatments.

Meta-analysis of use of balloon pulmonary angioplasty in patients with inoperable chronic thromboembolic pulmonary hypertension

BACKGROUND

Current guidelines give balloon pulmonary angioplasty (BPA) a Class IIb recommendation for use in inoperable chronic thromboembolic pulmonary hypertension (CTEPH), as its safety and efficacy remain poorly defined. We conducted a systematic review and meta-analysis to evaluate BPA effectiveness.

METHODS

Medline, Cochrane Library and Scopus were searched for original studies from database inception dates until 24th May 2018. Prospective studies reporting outcomes before and after BPA in inoperable CTEPH patients were included. Studies with <20 patients were excluded. Data were pooled using a random effects model represented as weighted mean differences with 95% confidence intervals (CIs).

RESULTS

Seventeen noncomparative studies comprising 670 CTEPH patients (mean age 62 years; 68% women) were included. Meta-analysis showed significantly decreased mean pulmonary artery pressure (-14.2 mm Hg [95% CI -18.9, -9.5]), pulmonary vascular resistance (-303.5 dyn·s/cm⁵ [95% CI -377.6, -229.4]) and mean right atrial pressure (-2.7 mm Hg [95% CI -4.1, -1.3]) after BPA. Six-minute walk distance (67.3 m [95% CI 53.8, 80.8]) and cardiac output (0.2 l/min [95% CI 0.0, 0.3]) were significantly increased following BPA. From 12 studies reporting mortality with median follow-up of 9 months after BPA (range, 1-51 months), pooled incidence of short (≤1 month) and long-term mortality (>1 month) was 1.9% and 5.7%, respectively.

CONCLUSION

This systematic review and meta-analysis suggests mildly improved hemodynamics and overall low mortality rates following BPA in inoperable CTEPH patients. This non-comparative evidence can be used to facilitate decision making until the results of larger, controlled studies become available.

Methods of Pharmacological Treatment of Chronic Thromboembolic Pulmonary Hypertension Current Approaches to the Patients Management

In this paper we have discussed epidemiology, pathogenesis, and approaches to treatment of chronic thromboembolic pulmonary hypertension (CTEPH). CTEPH is a unique potentially curable form of pulmonary hypertension. The gold standard of CTEPH treatment is pulmonary thromboendarterectomy. However, about 40% of patients with CTEPH are inoperable due to distal surgically inaccessible lesions of the pulmonary vasculature, severe hemodynamic impairments, or other contraindications. In addition, nearly half of patients have persistent or recurrent pulmonary hypertension following surgery. Current guidelines support the use of pharmacotherapy in these patients. In the article we have presented results of main clinical studies of targeted drugs therapy (endothelin receptor antagonists, prostanoids, phosphodiesterase type 5 inhibitors, soluble guanylate cyclase stimulators) of patients with CTEPH. The only drug that has demonstrated robust clinical efficacy in terms of improvment hemodynamic parameters, exercise capacity and patients' quality of life is the stimulator of the soluble guanylate cyclase riociguat. The efficacy and safety of riociguat have been investigated in short-term and long-term studies with follow-up up to 6 years. Results of these studies have constituted the basis forits approval by the regulatory authorities of more than 50 countries for the treatment of inoperable CTEPH and persistent or recurrent CTEPH after pulmonary thromboendarterectomy. In the European Union, USA and many other countries, riociguat is the only pharmacological agent approved for these indications.