Tadalafil therapy for pulmonary arterial hypertension.

Abstract

BACKGROUND:

Treatment options for pulmonary arterial hypertension target the prostacyclin, endothelin, or nitric oxide pathways. Tadalafil, a phosphodiesterase type-5 inhibitor, increases cGMP, the final mediator in the nitric oxide pathway.

METHODS AND RESULTS:

In this 16-week, double-blind, placebo-controlled study, 405 patients with pulmonary arterial hypertension (idiopathic or associated), either treatment-naive or on background therapy with the endothelin receptor antagonist bosentan, were randomized to placebo or tadalafil 2.5, 10, 20, or 40 mg orally once daily. The primary end point was the change from baseline to week 16 in the distance walked in 6 minutes. Changes in World Health Organization functional class, clinical worsening, and health-related quality of life were also assessed. Patients completing the 16-week study could enter a long-term extension study. Tadalafil increased the distance walked in 6 minutes in a dose-dependent manner; only the 40-mg dose met the prespecified level of statistical significance (P<0.01). Overall, the mean placebo-corrected treatment effect was 33 m (95% confidence interval, 15 to 50 m). In the bosentan-naive group, the treatment effect was 44 m (95% confidence interval, 20 to 69 m) compared with 23 m (95% confidence interval, -2 to 48 m) in patients on background bosentan therapy. Tadalafil 40 mg improved the time to clinical worsening (P=0.041), incidence of clinical worsening (68% relative risk reduction; P=0.038), and health-related quality of life. The changes in World Health Organization functional class were not statistically significant. The most common treatment-related adverse events reported with tadalafil were headache, myalgia, and flushing.

CONCLUSIONS:

In patients with pulmonary arterial hypertension, tadalafil 40 mg was well tolerated and improved exercise capacity and quality of life measures and reduced clinical worsening.

• Authors: Nazzareno Galiè, Bruce H Brundage, Hossein A Ghofrani, Ronald J Oudiz, Gerald Simonneau, Zeenat Safdar, Shelley Shapiro, R James White, Melanie Chan, Anthony Beardsworth, Lyn Frumkin, Robyn J Barst, Pulmonary Arterial Hypertension and Response to Tadalafil (PHIRST) Study Group
• Journal: Circulation (Circulation) Vol. 119 Issue 22 Pg. 2894-903 (Jun 09 2009) ISSN: 1524-4539 [Electronic] United States
• PMID: 19470885 (Publication Type: Journal Article, Randomized Controlled Trial, Research Support, Non-U.S. Gov't)

Chemical References

• Carbolines
• Endothelin Receptor Antagonists
• Phosphodiesterase Inhibitors
• Sulfonamides
• Tadalafil
• Bosentan

Topics

• Adult
• Aged
• Bosentan
• Carbolines (administration & dosage, adverse effects)
• Double-Blind Method
• Endothelin Receptor Antagonists
• Exercise Tolerance (drug effects)
• Female
• Humans
• Hypertension, Pulmonary (drug therapy)
• Male
• Middle Aged
• Phosphodiesterase Inhibitors (therapeutic use)
• Quality of Life
• Sulfonamides (therapeutic use)
• Tadalafil
• Treatment Outcome