Real-World Switching to Riociguat: Management and Practicalities in Patients with PAH and CTEPH

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 real-world use in patients with chronic thromboembolic pulmonary hypertension: A retrospective, observational cohort study in France

BACKGROUND

Riociguat is the first approved treatment for inoperable and persistent/recurrent post-surgery chronic thromboembolic pulmonary hypertension (CTEPH). The RetrospectIve Adempas® stuDy (RiAD) aimed to describe the real-world utilization of riociguat in France.

METHODS

In this retrospective multicentric study in patients initiating riociguat, dosing regimen, co-treatments and clinical characteristics were collected over a 2-year follow-up period.

RESULTS

A total of 173 patients (mean age, 71.4 years; female, 63.0%; NYHA II-III, 80.3%) were included from January 2015 to December 2016 in 18 centers. All patients were diagnosed with CTEPH (75.7% inoperable and 20.8% with persistent/recurrent pulmonary hypertension [pH] after surgery) with mean (SD) right atrial pressure 7.6 (4.2) mmHg, mean pulmonary artery pressure 43.0 (11.4) mmHg and mean cardiac output 4.1 (1.1) L/min. Before riociguat initiation, 32.4% of patients previously received at least one pH-specific therapy. At initiation, 93.1% of patients were receiving anticoagulants and 83.2% were not receiving pH-specific co-treatments. Riociguat was initiated at 1 mg three times daily (t.i.d.) in 85.5% of patients and 82.1% were receiving 2.5 mg dose t.i.d. at 24 months. The maximal daily dose of 7.5 mg was never exceeded. At 24 months, the estimated rate of patients still taking riociguat was 78.8% with an estimated mean (SD) time on treatment of 20.1 (0.5) months per patient. No new safety signals were recorded.

CONCLUSIONS

The results of this real-world study show that riociguat is used in France in accordance with its therapeutic indication in patients with inoperable or persistent/recurrent post-operative CTEPH and confirm its long-term safety.

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.

Evaluating Riociguat in the Treatment of Pulmonary Arterial Hypertension: A Real-World Perspective

Pulmonary hypertension (PH) is a broad term describing the mean pulmonary artery pressure, as measured by right heart catheterization, exceeds 20mmHg. Pulmonary arterial hypertension (PAH) exists when PH is accompanied by a normal wedge pressure and elevated pulmonary vascular resistance. PAH is typified by dysmorphic and dysfunctional pulmonary arterial vasculature. Attempting to restore the functionality of the pulmonary artery is a hallmark of care to the PAH patient. Riociguat is a powerful stimulator of soluble guanylate cyclase and increases blood flow through the pulmonary arteries by dilating vascular smooth muscle cells. This review examines the pharmacology of riociguat, the fundamental clinical trials applying it to PAH patients, practical aspects when selecting its use, and future directions for its utilization.

Differences in health policies for drug availability in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension across Latin America

Treatment for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension in Latin America differs between countries, with regard to disease etiology, health insurance coverage, and drug availability. A group of experts from Latin America, met to share regional experiences and propose possible lines of collaboration. The available evidence, regional clinical practice data, and the global context of the proceedings of the 6th World Symposium on Pulmonary Hypertension, held in Nice, France, in February 2018, were analyzed. Here, we discuss some priority concepts identified that could guide transnational interaction and research strategies in Latin America: (1) despite being evidence‐based, the 6th World Symposium on Pulmonary Hypertension proceedings may not be applicable in Latin American countries; (2) proactive identification and diagnosis of patients in Latin America is needed; (3) education of physicians and standardization of appropriate treatment for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension is vital; (4) our clinical experience for the treatment strategy for pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension is based on drug availability in Argentina, Brazil, Colombia and México; (5) there are difficulties inherent to the consultation of patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension, and access to treatment; (6) the importance of data generation and research of Latin American‐specific issues related to pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension is highlighted.

Novel use of riociguat in infants with severe pulmonary arterial hypertension unable to wean from inhaled nitric oxide

INTRODUCTION

Riociguat, an oral soluble guanylate cyclase stimulator, has been approved for use in adults with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension. However, there is limited data on its therapeutic use in children.

CASE PRESENTATION

We report the case of two infants with severe suprasystemic pulmonary hypertension who were successfully treated with riociguat after failure to wean off inhaled nitric oxide (iNO) despite combination PAH therapy. Case 1 is a 6-month-old term male with TBX4 deletion who presented with severe hypoxemic respiratory failure and severe PAH immediately after birth. Initial cardiac catheterization showed PVRi 15.5 WU*m2. Marked hypoxemia and PAH persisted despite aggressive therapy with sildenafil, bosentan, intravenous treprostinil, and milrinone. The infant required high doses of inhaled nitric oxide (60 ppm) and manifested significant post-ductal hypoxemia and hemodynamic instability with any attempt at weaning. After discontinuation of sildenafil, initiation, and very slow uptitration of riociguat, the patient was able to maintain hemodynamic stability and wean from nitric oxide over 6 weeks with persistently severe but not worsened pulmonary hypertension. Case 2 is a 4-month-old term male with compound heterozygous SLC25A26 mutation and severe pulmonary hypertension. Initial cardiac catheterization showed PVRi 28.2 WU*m2. After uptitration of sildenafil, bosentan, and IV treprostinil, serial echocardiograms continued to demonstrate near-systemic pulmonary hypertension. He failed multiple attempts to wean off typical doses of iNO (10-20 ppm) over the following weeks with tachypnea, hypoxemia, and worsening pulmonary hypertension on echocardiogram despite continued aggressive combination targeted therapy. After a 24-h sildenafil washout, he was initiated and uptitrated on riociguat with concomitant, successful wean of nitric oxide over one week that was well tolerated. No serious adverse effects in the titration period were observed.

CONCLUSION

Riociguat may be considered as an adjuvant therapeutic agent in selected children with severe PAH who are poorly responsive to sildenafil therapy and unable to wean from iNO.

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.

Switching Strategy in the Management of Patients with Pulmonary Arterial Hypertension. The REPLACE Study Results

The article is devoted to topical issues of management of patients with pulmonary arterial hypertension and strategies for switching to riociguat therapy in patients with insufficient clinical response against the background of phosphodiesterase type 5 (PDE-5) inhibitors. The role of the NO metabolic pathway in the development of pulmonary arterial hypertension (PAH) was shown. From the standpoint of pathogenesis, the importance of the effect of medication on this pathway through soluble guanylate cyclase (sGC) has been assessed. The effects of the drug riociguat, the only member of the sGC stimulant class approved for the treatment of PAH, are associated with a dual mechanism of action: riociguat sensitizes the sGC enzyme to endogenous NO by stabilizing the NO-sGC bond, and also directly stimulates the latter through another site of the bond, regardless of NO. The favorable efficacy and safety profile of riociguat has been demonstrated in the PATENT-1,2 studies. During therapy, patients showed an improvement in exercise tolerance, functional class, and a number of other indicators. Studies that indicate the feasibility of using a change in therapy in clinical practice are reviewed. In particular, the article provides a detailed analysis of the REPLACE study. It demonstrated a significantly greater likelihood of achieving clinical improvement and a significant decrease in the rate of development of clinical deterioration when switching patients with PAH from PDE-5 inhibitors to riociguat. This therapy was well tolerated and can be considered as a strategy for managing patients at intermediate risk with insufficient patient response to PDE-5 inhibitors. In conclusion, the need to plan the need for specific therapy for pulmonary arterial hypertension in the region is noted in order to rapidly escalate therapy to achieve a low risk of mortality in these patients.

[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).

[The soluble guanylate cyclase stimulator riociguat is the first-line therapy for chronic thromboembolic pulmonary hypertension patients]

Chronic thromboembolic pulmonary hypertension (CTEPH) is a precapillary type of pulmonary hypertension with chronic obstruction of large and medium branches of pulmonary arteries along with secondary alterations in pulmonary microcirculation, which cause progressive increases in pulmonary vascular resistance and pulmonary arterial pressure and ensuing severe right heart dysfunction and heart failure. Pulmonary thromboendarterectomy (PTE) is the treatment of choice for CTEPH; however, this procedure is available not for all patients. Although the surgery performed in the conditions of centers with advanced experience generally shows good results, up to 40% of patients are technically inoperable or PTE is associated with a high risk of complications. At present, riociguat, the only officially approved drug from the class of soluble guanylate cyclase stimulators, is considered as a first-line treatment for inoperable and residual forms of STEPH. Introduction of riociguat to clinical practice can be called a real breakthrough in the treatment of patients with STEPH who cannot undergo PTE or those with relapse or persistent STEPH after the surgery.

Riociguat in the Treatment of Chronic Thromboembolic Pulmonary Hypertension: An Evidence-Based Review of Its Place in Therapy

Chronic thromboembolic pulmonary hypertension (CTEPH) is classified as group-4 pulmonary hypertension caused by organized thrombi in pulmonary arteries and vasculopathy in nonoccluded areas leading to right heart failure and death. In addition to chronic anticoagulation therapy, each patient with CTEPH should receive treatment assessment starting with evaluation for pulmonary endarterectomy (PEA), which is the guideline recommended treatment. There is increasing experience with balloon pulmonary angioplasty (BPA) for inoperable patients; this option, like PEA, is reserved for specialized centers with expertise in this treatment method. Inoperable patients are candidates for targeted drug therapy. Riociguat remains the only approved medical therapy for CTEPH patients deemed inoperable or with persistent pulmonary hypertension after PEA. The role of riociguat therapy preoperatively or in tandem with BPA is currently under investigation. The purpose of this review is to evaluate the safety and efficacy of riociguat in the treatment of CTEPH.

Advances in targeted therapy for chronic thromboembolic pulmonary hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is characterized by unresolved thrombi in the pulmonary arteries and microvasculopathy in nonoccluded areas. If left untreated, progressive pulmonary hypertension will induce right heart failure and, finally, death. Currently, pulmonary endarterectomy (PEA) remains the only method that has the potential to cure CTEPH. Unfortunately, up to 40% of patients are ineligible for this procedure for various reasons. In recent years, refined balloon pulmonary angioplasty (BPA) has become an alternative option for inoperable CTEPH patients, and it may be another curative treatment in the future, particularly in combination with prior PEA. Nevertheless, 23% of patients still suffer from persistent PH after BPA. Given that CTEPH shares many similarities with idiopathic pulmonary arterial hypertension (PAH), targeted drugs developed for PAH are also attractive options for CTEPH, especially for inoperable or persistent/recurrent CTEPH patients. To date, riociguat, macitentan, and subcutaneous treprostinil are the only drugs proven by randomized control trials to be capable of improving the exercise capacity (6-min walking distance) of CTEPH patients. In this review, we summarize the achievements and unresolved problems of PAH-targeted therapy for CTEPH over the last decade.

Practical management of riociguat in patients with pulmonary arterial hypertension

Riociguat is one of several approved therapies available for patients with pulmonary arterial hypertension (PAH). Treatment should be initiated and monitored at an expert center by a physician experienced in treating PAH, and the dose adjusted in the absence of signs and symptoms of hypotension. In certain populations, including patients with hepatic or renal impairment, the elderly, and smokers, riociguat exposure may differ, and dose adjustments should therefore be made with caution according to the established scheme. Common adverse events are often easily managed, particularly if they are discussed before starting therapy. Combination therapy with riociguat and other PAH-targeted agents is feasible and generally well tolerated, although the coadministration of phosphodiesterase type 5 inhibitors (PDE5i) and riociguat is contraindicated. An open-label, randomized study is currently ongoing to assess whether patients who do not achieve treatment goals while receiving PDE5i may benefit from switching to riociguat. In this review, we provide a clinical view on the practical management of patients with PAH receiving riociguat, with a focus on the opinions and personal experience of the authors. The reviews of this paper are available via the supplemental material section.

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.