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The changing paradigm in pulmonary hypertension trials

longer duration, new endpoints

LeVarge, Barbara L.a; Channick, Richard N.b

Current Opinion in Pulmonary Medicine: September 2015 - Volume 21 - Issue 5 - p 438–445
doi: 10.1097/MCP.0000000000000197
DISORDERS OF THE PULMONARY CIRCULATION: Edited by Richard N. Channick and Marc Humbert
Editor's Choice

Purpose of review Approved therapies for pulmonary arterial hypertension (PAH) currently consist of 12 agents, the majority of which were approved following short-term randomized clinical trials using change in 6 minute walk distance (6MWD) as the primary outcome. However, there is growing concern that significant improvements in this measure do not translate into morbidity and mortality benefits.

Recent findings As a result of data questioning the association between improvements in 6 minute walk distance and improvements in outcome, PAH clinical trial design is increasingly utilizing morbidity and mortality events as a composite primary outcome. This concept was recently illustrated in the published phase 3 trial of macitentan versus placebo, during which the clinical worsening event rate was decreased by 45%. Several additional unpublished trials have been similarly designed, all of which will require extended blinded treatment time in order to accrue sufficient event rates. The definition of morbidity events has varied across clinical studies; further standardization of this parameter is necessary.

Summary Although multiple direct and surrogate outcomes have been studied in PAH clinical research, rate of clinical worsening events, using prolonged, event-driven trial design, has emerged as the new standard.

aDepartment of Pulmonary and Critical Care Medicine, Beth Israel Deaconess Medical Center

bDepartment of Pulmonary and Critical Care Medicine, Massachusetts General Hospital, Boston, Massachusetts, USA

Correspondence to Barbara L. LeVarge, MD, Department of Pulmonary and Critical Care Medicine, Beth Israel Deaconess Medical Center, 330 Brookline Avenue, Boston, MA, 02215. Tel: +1 617 667 5864; e-mail:

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