lu-208075 and Dyspnea

Ambrisentan is a propanoic acid-based, A-selective endothelin receptor antagonist for the once-daily treatment of pulmonary arterial hypertension.. Ambrisentan in Pulmonary Arterial Hypertension, Randomized, Double-Blind, Placebo-Controlled, Multicenter, Efficacy Study 1 and 2 (ARIES-1 and ARIES-2) were concurrent, double-blind, placebo-controlled studies that randomized 202 and 192 patients with pulmonary arterial hypertension, respectively, to placebo or ambrisentan (ARIES-1, 5 or 10 mg; ARIES-2, 2.5 or 5 mg) orally once daily for 12 weeks. The primary end point for each study was change in 6-minute walk distance from baseline to week 12. Clinical worsening, World Health Organization functional class, Short Form-36 Health Survey score, Borg dyspnea score, and B-type natriuretic peptide plasma concentrations also were assessed. In addition, a long-term extension study was performed. The 6-minute walk distance increased in all ambrisentan groups; mean placebo-corrected treatment effects were 31 m (P=0.008) and 51 m (P<0.001) in ARIES-1 for 5 and 10 mg ambrisentan, respectively, and 32 m (P=0.022) and 59 m (P<0.001) in ARIES-2 for 2.5 and 5 mg ambrisentan, respectively. Improvements in time to clinical worsening (ARIES-2), World Health Organization functional class (ARIES-1), Short Form-36 score (ARIES-2), Borg dyspnea score (both studies), and B-type natriuretic peptide (both studies) were observed. No patient treated with ambrisentan developed aminotransferase concentrations >3 times the upper limit of normal. In 280 patients completing 48 weeks of treatment with ambrisentan monotherapy, the improvement from baseline in 6-minute walk at 48 weeks was 39 m.. Ambrisentan improves exercise capacity in patients with pulmonary arterial hypertension. Improvements were observed for several secondary end points in each of the studies, although statistical significance was more variable. Ambrisentan is well tolerated and is associated with a low risk of aminotransferase abnormalities.

Topics: Activities of Daily Living; Administration, Oral; Aged; Double-Blind Method; Dyspnea; Endothelin Receptor Antagonists; Exercise; Female; Follow-Up Studies; Humans; Hypertension, Pulmonary; Kaplan-Meier Estimate; Male; Middle Aged; Natriuretic Peptide, Brain; Phenylpropionates; Placebos; Pyridazines; Quality of Life; Treatment Outcome

Topics: Acetamides; Adolescent; Antihypertensive Agents; Asymptomatic Diseases; Bone Morphogenetic Protein Receptors, Type II; Cardiac Catheterization; Disease Progression; Dyspnea; Echocardiography; Exercise Tolerance; Female; Genetic Testing; Heterozygote; Humans; Male; Phenylpropionates; Pulmonary Arterial Hypertension; Pyrazines; Pyridazines; Sildenafil Citrate; Syncope; Vasodilator Agents

Topics: Antihypertensive Agents; Diagnosis, Differential; Dyspnea; Female; Humans; Hypertension, Pulmonary; Middle Aged; Phenylpropionates; Pyridazines; Thrombocytopenia

4-Aminopyridine (4-AP) is a recent treatment indicated to improve walking in patient with multiple sclerosis. We report the first case of pulmonary arterial hypertension (PAH) that we attribute to the use of 4-AP. A 64-year-old woman with multiple sclerosis presented with dyspnea. After excluding other secondary causes of pulmonary hypertension, a diagnosis of severe PAH due to 4-AP was made based on right heart catheterization. History revealed that the dyspnea began with the initiation of 4-AP. After discontinuation of 4-AP therapy and initiation of ambrisentan and tadalafil, dyspnea and pulmonary arterial pressure have improved significantly and one specific PAH treatment was stopped. 4-AP is an outward rectifying potassium channel blocker with a vasoconstrictor effect in animal's pulmonary artery. According to the chronological sequence of events, the lack of other etiology, and its pharmacological plausibility, 4-AP is highly suspected to have induced our patient's PAH.

Topics: 4-Aminopyridine; Antihypertensive Agents; Dyspnea; Female; Humans; Hypertension, Pulmonary; Middle Aged; Multiple Sclerosis; Phenylpropionates; Potassium Channel Blockers; Pyridazines; Tadalafil

Currently available endothelin receptor antagonists for treating pulmonary arterial hypertension block either the endothelin (ET) receptor A or both A and B receptors. Transition from one endothelin receptor antagonist to another may theoretically alter side-effects or efficacy. We report our experience of a transition from sitaxsentan to ambrisentan, both predominant ET(A) receptor antagonists, in pulmonary arterial hypertension patients.. At Baylor Pulmonary Hypertension Center, 18 patients enrolled in the open-label extension phase of the original sitaxsentan studies (Sitaxsentan To Relieve ImpaireD Exercise) were transitioned to ambrisentan (from July 2007 to September 2007) at the time of study closure. Pre-transition (PreT), 1 month (1Mth) and 1 year (1Yr) post-transition assessments of 6-minute walk distance (6MWD), brain naturetic peptide (BNP) levels, WHO functional class (WHO FC), Borg dyspnea score (BDS), oxygen saturation, liver function, and peripheral edema were compared.. 6MWD was 356 ± 126 m at PreT, 361 ± 125 m at 1Mth, and 394 ± 114 m at 1Yr (mean ± SD). There was no difference in the walk distance at 1Mth and 1Yr post transition compared with PreT (P=0.92, 0.41 respectively). Oxygen saturation was no different at 1Mth and 1Yr to PreT level (P=0.49 and P=0.06 respectively). BNP was 178 ± 44 pg/mL at PreT, 129 ± 144 pg/mL at 1Mth and 157 ± 201 at 1Yr. Peripheral edema was present in 7/18 patients at PreT, in 8/16 patients at 1Mth, and in 6/13 patients at 1Yr post transition. Proportions of patients with edema over these 3 time points did not change significantly (P=0.803). At 1Yr, 2 patients had died, 1 had undergone lung transplantation, 1 had relocated, and 1 patient was started on intravenous prostacyclin therapy. Over 3 points (baseline, 1 month, and 1 year), there was no significant change in function class (P=0.672).. Our limited data suggest that ET(A) receptor antagonists can be switched from one to another with sustained exercise capacity and maintained WHO FC with no increase in incidence of peripheral edema.

Topics: Adult; Aged; Antihypertensive Agents; Blood Pressure; Drug Substitution; Dyspnea; Edema; Endothelin A Receptor Antagonists; Exercise Test; Exercise Tolerance; Familial Primary Pulmonary Hypertension; Female; Humans; Hypertension, Pulmonary; Isoxazoles; Liver Function Tests; Male; Middle Aged; Natriuretic Peptide, Brain; Oxygen; Phenylpropionates; Pyridazines; Retrospective Studies; Texas; Thiophenes; Time Factors; Treatment Outcome; Walking