Effect of riociguat on right ventricular function in patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension.

BACKGROUND: In the Phase III PATENT-1 (NCT00810693) and CHEST-1 (NCT00855465) studies, riociguat demonstrated efficacy vs placebo in patients with pulmonary arterial hypertension (PAH) and chronic thromboembolic pulmonary hypertension (CTEPH). Clinical effects were maintained at 2 years in the long-term extension studies PATENT-2 (NCT00863681) and CHEST-2 (NCT00910429). METHODS: This post hoc analysis of hemodynamic data from PATENT-1 and CHEST-1 assessed whether riociguat improved right ventricular (RV) function parameters including stroke volume index (SVI), stroke volume, RV work index, and cardiac efficiency. REVEAL Risk Score (RRS) was calculated for patients stratified by SVI and right atrial pressure (RAP) at baseline and follow-up. The association between RV function parameters and SVI and RAP stratification with long-term outcomes was assessed. RESULTS: In PATENT-1 (n = 341) and CHEST-1 (n = 238), riociguat improved RV function parameters vs placebo (p < 0.05). At follow-up, there were significant differences in RRS between patients with favorable and unfavorable SVI and RAP, irrespective of treatment arm (p < 0.0001). Multiple RV function parameters at baseline and follow-up were associated with survival and clinical worsening-free survival (CWFS) in PATENT-2 (n = 396; p < 0.05) and CHEST-2 (n = 237). In PATENT-2, favorable SVI and RAP at follow-up only was associated with survival and CWFS (p < 0.05), while in CHEST-2, favorable SVI and RAP at baseline and follow-up were associated with survival and CWFS (p < 0.05). CONCLUSION: This post hoc analysis of PATENT and CHEST suggests that riociguat improves RV function in patients with PAH and CTEPH.

Impact of lung morphology on clinical outcomes with riociguat in patients with pulmonary hypertension and idiopathic interstitial pneumonia: A post hoc subgroup analysis of the RISE-IIP study.

BACKGROUND: Riociguat in Patients with Symptomatic Pulmonary Hypertension associated with Idiopathic Interstitial Pneumonias (RISE-IIP), a randomized, controlled, phase 2b trial of riociguat for pulmonary hypertension associated with idiopathic interstitial pneumonia, was terminated early due to increased mortality in riociguat-treated patients. Baseline characteristics of enrolled patients demonstrated a low diffusing capacity of the lung for carbon monoxide (DLCO) with preserved lung volumes at baseline, suggesting the presence of combined pulmonary fibrosis and emphysema (CPFE) in some patients. This post hoc analysis of RISE-IIP was undertaken to explore lung morphology, assessed by high-resolution computed tomography, and associated clinical outcomes. METHODS: Available baseline/pre-baseline high-resolution computed tomography scans were reviewed centrally by 2 radiologists. The extent of emphysema and fibrosis was retrospectively scored and combined to provide the total CPFE score. RESULTS: Data were available for 65/147 patients (44%), including 15/27 fatal cases (56%). Of these, 41/65 patients (63%) had CPFE. Mortality was higher in patients with CPFE (12/41; 29%) than those without (3/24; 13%). Fourteen patients with CPFE had emphysema > fibrosis (4 died). No relationship was observed between CPFE score, survival status, and treatment assignment. A low DLCO, short 6-min walking distance, and high forced vital capacity:DLCO ratio at baseline also appeared to be risk factors for mortality. CONCLUSIONS: High parenchymal lung disease burden and the presence of more emphysema than fibrosis might have predisposed patients with pulmonary hypertension associated with idiopathic interstitial pneumonia to poor outcomes in RISE-IIP. Future studies of therapy for group 3 pulmonary hypertension should include centrally adjudicated imaging for morphologic phenotyping and disease burden evaluation during screening.

Assessment of the REPLACE study composite endpoint in riociguat-treated patients in the PATENT study.

The goal of treatment in patients with pulmonary arterial hypertension is to achieve a low risk status, indicating a favorable long-term outcome. The REPLACE study investigated the efficacy of switching to riociguat in patients with pulmonary arterial hypertension and an insufficient response to phosphodiesterase-5 inhibitors. In this post hoc analysis, we applied the REPLACE composite endpoint of clinical improvement to the placebo-controlled PATENT-1 study of riociguat in pulmonary arterial hypertension and its long-term extension, PATENT-2. Clinical improvement was defined as ≥2 of the following in patients who completed the study without clinical worsening: ≥10% or ≥30 m improvement in 6-minute walking distance; World Health Organization functional class I or II; ≥30% decrease in N-terminal prohormone of brain natriuretic peptide. At PATENT-1 Week 12, patients treated with riociguat were more likely to achieve the composite endpoint vs. placebo (P < 0.0001), with similar results in pretreated (P = 0.0189) and treatment-naïve (P < 0.0001) patients. Achievement of the composite endpoint at Week 12 was associated with a 45% reduction in relative risk of death and a 19% reduction in relative risk of clinical worsening in PATENT-2. Overall, these data suggest that use of the REPLACE composite endpoint in patients with pulmonary arterial hypertension is a valid assessment of response to treatment.

Effect of riociguat on pulmonary arterial compliance in the PATENT and CHEST studies.

Pulmonary arterial compliance is a measure of the pulsatile afterload of the right ventricle. Lower pulmonary arterial compliance is associated with reduced right ventricular function and worse prognosis in pulmonary hypertension. The effect of pulmonary vasodilators on pulmonary arterial compliance has not been evaluated in detail in pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. In this post hoc analysis of patients with pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension in the PATENT and CHEST studies, we evaluated the change in pulmonary arterial compliance with riociguat versus placebo. Association of pulmonary arterial compliance with clinical outcomes was assessed using Kaplan-Meier and Cox proportional hazards analyses. Compared with placebo, riociguat significantly improved pulmonary arterial compliance in patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. Pulmonary arterial compliance at baseline was associated with survival and clinical worsening-free survival in pulmonary arterial hypertension but only with clinical worsening-free survival in chronic thromboembolic pulmonary hypertension. In patients with pulmonary arterial hypertension, pulmonary arterial compliance at follow-up ≥1.6 mL/mmHg was associated with better outcomes than pulmonary arterial compliance <1.6 mL/mmHg. In patients with chronic thromboembolic pulmonary hypertension, pulmonary arterial compliance at follow-up did not predict outcomes. Cox proportional hazards analyses showed no association between change in pulmonary arterial compliance and outcomes in patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. In conclusion, riociguat improved pulmonary arterial compliance in patients with pulmonary arterial hypertension or chronic thromboembolic pulmonary hypertension. Pulmonary arterial compliance at baseline or follow-up, rather than change in pulmonary arterial compliance, is of prognostic importance for outcomes.

Efficacy and safety of riociguat in combination therapy for patients with pulmonary arterial hypertension (PATENT studies).

Many patients with pulmonary arterial hypertension do not achieve treatment goals with monotherapy, and therefore combination therapy is becoming the standard of care. The soluble guanylate cyclase stimulator riociguat is licensed for the treatment of pulmonary arterial hypertension; here we present findings from patients who were receiving combined riociguat plus endothelin receptor antagonists or non-intravenous prostanoids in the randomized, placebo-controlled PATENT-1 study and its open-label extension (PATENT-2). Moreover, we include new data from patients receiving early sequential combination therapy (three to six months of endothelin receptor antagonist treatment) or long-term background endothelin receptor antagonist therapy (>6 months). Patients were randomized to riociguat 2.5 mg-maximum (N = 131 pretreated patients) and placebo (N = 60 pretreated patients). Riociguat improved 6-min walking distance (PATENT-1 primary endpoint), functional capacity, and hemodynamics after 12 weeks in pretreated patients. The placebo-corrected changes in 6-min walking distance were +24 m in endothelin receptor antagonist-pretreated patients and +106 m in the small group of prostanoid-pretreated patients. In the early sequential combination and long-term background endothelin receptor antagonist groups, the placebo-corrected changes in 6-min walking distance were +65 m (95% CI: 17 to 113 m) and +13 m (95% CI: -8 to 33 m), respectively. In conclusion, these data suggest that early sequential combination of an endothelin receptor antagonist plus riociguat is a feasible treatment option. Both early sequential therapy and long-term background endothelin receptor antagonist plus riociguat were well tolerated in the PATENT studies.

Identifying potential parameters associated with response to switching from a PDE5i to riociguat in RESPITE.

BACKGROUND: RESPITE evaluated patients with pulmonary arterial hypertension and an inadequate response to phosphodiesterase type 5 inhibitors (PDE5i) who switched to riociguat. This post hoc analysis assessed response to this switch in parameters associated with clinical improvement. METHODS: RESPITE was a 24-week, uncontrolled pilot study (n = 61). Differences in functional, hemodynamic, and cardiac function parameters, REVEAL risk score (RRS), and biomarkers were compared between responders (free from clinical worsening, World Health Organization functional class I/II, and ≥30 m improvement in 6-min walking distance at Week 24) and non-responders. RESULTS: Of 51 patients (84%) completing RESPITE, 16 (31%) met the responder endpoint. At baseline, there were significant differences between responders and non-responders in N-terminal prohormone of brain natriuretic peptide (NT-proBNP), growth/differentiation factor 15 (GDF-15), and RRS, whereas there were no differences in hemodynamics or cardiac function. At Week 24, responders had significant improvements in pulmonary arterial compliance, pulmonary vascular resistance, and mean pulmonary arterial pressure, while non-responders showed no significant change. Cardiac efficiency and stroke volume index significantly improved irrespective of responder status. CONCLUSIONS: NT-proBNP, GDF-15, and RRS were identified as potential predictors of response in patients switching from PDE5i to riociguat. Further prospective controlled studies are needed to confirm the association of these parameters with response.

Risk assessment in pulmonary arterial hypertension and chronic thromboembolic pulmonary hypertension.

BACKGROUND: Current pulmonary hypertension treatment guidelines recommend use of a risk stratification model encompassing a range of parameters, allowing patients to be categorised as low, intermediate or high risk. Three abbreviated versions of this risk stratification model were previously evaluated in patients with pulmonary arterial hypertension (PAH) in the French, Swedish and COMPERA registries. Our objective was to investigate the three abbreviated risk stratification methods for patients with mostly prevalent PAH and chronic thromboembolic pulmonary hypertension (CTEPH), in patients from the PATENT-1/2 and CHEST-1/2 studies of riociguat. METHODS: Risk was assessed at baseline and at follow-up in PATENT-1 and CHEST-1. Survival and clinical worsening-free survival were assessed in patients in each risk group/strata. RESULTS: With all three methods, riociguat improved risk group/strata in patients with PAH after 12 weeks. The French non-invasive and Swedish/COMPERA methods discriminated prognosis for survival and clinical worsening-free survival at both baseline and follow-up. Furthermore, patients achieving one or more low-risk criteria or a low-risk stratum at follow-up had a significantly reduced risk of death and clinical worsening compared with patients achieving no low-risk criteria or an intermediate-risk stratum. Similar results were obtained in patients with inoperable or persistent/recurrent CTEPH. CONCLUSIONS: This analysis confirms and extends the results of the registry analyses, supporting the value of goal-oriented treatment in PAH. Further assessment of these methods in patients with CTEPH is warranted.

REVEAL risk score in patients with chronic thromboembolic pulmonary hypertension receiving riociguat.

BACKGROUND: The REVEAL risk score (RRS) was developed to predict survival in patients with pulmonary arterial hypertension (PAH), based on multiple patient characteristics. Herein we calculated RRS for patients in the randomized CHEST-1 study and open-label CHEST-2 extension study of riociguat in inoperable or persistent/recurrent chronic thromboembolic pulmonary hypertension (CTEPH). We investigated the effect of riociguat vs placebo on RRS in the CHEST-1 study, and the relationship between RRS and long-term outcomes in the CHEST-2 study. METHODS: RRS was calculated post hoc for baseline and Week 16 of CHEST-1 and Week 12 of CHEST-2, based on 9 evaluable elements. Patients were grouped into risk strata by RRS. Relationships between RRS and both survival and clinical worsening-free survival were examined by Kaplan-Meier and Cox proportional hazards analyses. RESULTS: Overall, 237 patients completed CHEST-1 and entered CHEST-2. In CHEST-1, riociguat significantly improved RRS (p < 0.0001) and risk stratum (p < 0.001) vs placebo from baseline to Week 16. RRS at baseline, and at Week 16, and change in RRS during CHEST-1 were significantly associated with survival (hazard ratios for a 1-point reduction in RRS: 0.702, 0.692, and 0.682, respectively) and clinical worsening-free survival (hazard ratios: 0.697, 0.719, and 0.754, respectively) over 2 years in CHEST-2. CONCLUSIONS: Riociguat improved RRS in patients with inoperable and persistent/recurrent CTEPH. RRS at baseline and Week 16, and change in RRS from baseline, predicted survival and clinical worsening-free survival. This analysis of RRS in patients with inoperable or persistent/recurrent CTEPH suggests utility for the RRS in indications beyond PAH.

REVEAL risk scores applied to riociguat-treated patients in PATENT-2: Impact of changes in risk score on survival.

BACKGROUND: The Registry to Evaluate Early and Long-term PAH Disease Management (REVEAL) risk score (RRS) calculator was developed using data derived from the REVEAL registry, and predicts survival in patients with pulmonary arterial hypertension (PAH) based on multiple patient characteristics. Herein we applied the RRS to a pivotal PAH trial database, the 12-week PATENT-1 and open-label PATENT-2 extension studies of riociguat. We examined the effect of riociguat vs placebo on RRS in PATENT-1, and investigated the prognostic implications of change in RRS during PATENT-1 on long-term outcomes in PATENT-2. METHODS: RRS was calculated post hoc for baseline and Week 12 of PATENT-1, and Week 12 of PATENT-2. Patients were grouped into risk strata by RRS. Kaplan-Meier estimates were made for survival and clinical worsening-free survival in PATENT-2 to evaluate the relationship between RRS in PATENT-1 and long-term outcomes in PATENT-2. RESULTS: A total of 396 patients completed PATENT-1 and participated in PATENT-2. In PATENT-1, riociguat significantly improved RRS (p = 0.031) and risk stratum (p = 0.018) between baseline and Week 12 compared with placebo. RRS at baseline, and at PATENT-1 Week 12, and change in RRS during PATENT-1 were significantly associated with survival (hazard ratios for a 1-point reduction in RRS: 0.675, 0.705 and 0.804, respectively) and clinical worsening-free survival (hazard ratios of 0.736, 0.716 and 0.753, respectively) over 2 years in PATENT-2. CONCLUSIONS: RRS at baseline and Week 12, and change in RRS, were significant predictors of both survival and clinical worsening-free survival. These data support the long-term predictive value of the RRS in a controlled study population.

RESPITE: switching to riociguat in pulmonary arterial hypertension patients with inadequate response to phosphodiesterase-5 inhibitors.

A proportion of pulmonary arterial hypertension (PAH) patients do not reach treatment goals with phosphodiesterase-5 inhibitors (PDE5i). RESPITE investigated the safety, feasibility and benefit of switching from PDE5i to riociguat in these patients.RESPITE was a 24-week, open-label, multicentre, uncontrolled study. Patients in World Health Organization (WHO) functional class (FC) III, with 6-min walking distance (6MWD) 165-440 m, cardiac index <3.0 L·min-1·m-2 and pulmonary vascular resistance >400 dyn·s·cm-5 underwent a 1-3 day PDE5i treatment-free period before receiving riociguat adjusted up to 2.5 mg maximum t.i.d Exploratory end-points included change in 6MWD, WHO FC, N-terminal prohormone of brain natriuretic peptide (NT-proBNP) and safety.Of 61 patients enrolled, 51 (84%) completed RESPITE. 50 (82%) were receiving concomitant endothelin receptor antagonists. At week 24, mean±sd 6MWD had increased by 31±63 m, NT-proBNP decreased by 347±1235 pg·mL-1 and WHO FC improved in 28 patients (54%). 32 patients (52%) experienced study drug-related adverse events and 10 (16%) experienced serious adverse events (2 (3%) study drug-related, none during the PDE5i treatment-free period). Six patients (10%) experienced clinical worsening, including death in two (not study drug-related).In conclusion, selected patients with PAH may benefit from switching from PDE5i to riociguat, but this strategy needs to be further studied.