The 6-min walk test (6MW) as an efficacy endpoint in pulmonary arterial hypertension clinical trials: demonstration of a ceiling effect.
ABSTRACT PAH trials traditionally use 6MW as the primary endpoint. Concerns regarding a "ceiling effect" masking efficacy have led to exclusion of patients with milder disease from most trials (BL 6MW>450 m). STRIDE I evaluated the selective endothelin A receptor antagonist, sitaxsentan (SITAX), in a 12-week randomized, double-blind, trial (178 patients) employing placebo (PBO), 100 mg or 300 mg SITAX orally once daily in PAH and included patients with NYHA class II, congenital heart disease and a BL 6MW>450 m, groups often excluded from previous trials.
We analyzed 6MW effects For All Pts (intention-to treat) and those meeting Traditional enrollment criteria, defined as patients with NYHA class III or IV and 6MW< or =450 m at BL with idiopathic PAH or PAH related to connective tissue disease. The 100 mg and 300 mg SITAX arms are pooled based on similar treatment effects on 6MW.
Existence of a "ceiling effect" is supported by these data. The magnitude of the treatment effect and statistical power when using 6MW as the endpoint. Comparisons between PAH trials that do not adjust for the effects of differing enrollment criteria require caution.
Article: A dosing/cross-development study of the multikinase inhibitor sorafenib in patients with pulmonary arterial hypertension.[show abstract] [hide abstract]
ABSTRACT: Pulmonary arterial hypertension (PAH) and cancer share elements of pathophysiology. This provides an opportunity for the cross-development of anticancer agents that can be used in improving PAH care. The adaptation of new drugs across these disease populations warrants a structured approach. This study was a 16-week, phase Ib, single-center, open-label trial of the multikinase/angiogenesis inhibitor sorafenib. In order to assess the safety of sorafenib in PAH, patients with advanced but stable disease on parenteral prostanoids (with or without oral sildenafil) were initiated on treatment at the lowest active dosage administered to cancer patients: 200 mg daily. Patients underwent weekly clinical evaluations and monthly functional testing and dose escalations to a final dosage of 400 mg twice daily. Among 12 patients (10 of them women), sorafenib was well tolerated at 200 mg twice daily. The most common adverse events were moderate skin reactions on the hands and feet and alopecia. Our conclusion was therefore that this is a tolerable dosing regimen for testing the therapeutic activity of sorafenib in PAH patients.Clinical Pharmacology & Therapeutics 12/2009; 87(3):303-10. · 6.04 Impact Factor
Article: Assessing physical function and activity for survivors of a critical illness: a review of instruments.[show abstract] [hide abstract]
ABSTRACT: Functional outcomes and health-related quality of life are important measures for survivors of a critical illness. Studies have demonstrated debilitating physical effects for a significant proportion of surviving patients, particularly those with intensive care unit-acquired weakness. Contemporary practice changes include a focus on the continuum of critical illness, with less sedation and more physical activity including mobility while in ICU, and post-ICU and post-hospitalisation activities to support optimal recovery. How to best assess the physical function of patients at different phases of their recovery and rehabilitation is therefore important. This narrative review paper examined observational and functional assessment instruments used for assessing patients across the in-ICU, post-ICU and post-hospital continuum of critical illness. Relevant papers were identified from a search of bibliographic databases and a review of the reference list of selected articles. The clinimetric properties of physical function and HRQOL measures and their relevance and utility in ICU were reported in narrative format. The review highlighted many different instruments used to measure function in survivors of ICU including muscle strength testing, functional tests and walk tests, and patient centred outcomes such as health related quality of life. In general, the sensitivity and validity of these instruments for use with survivors of a critical illness has not yet been established. Based on findings from the review, screening of patients using reliable and valid instruments for ICU patients is recommended to inform both practice and future studies of interventions aimed at improving recovery and rehabilitation.Australian Critical Care 06/2011; 24(3):155-66. · 0.97 Impact Factor
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ABSTRACT: There has been an increase in lung transplantation in the USA. Lung allocation is guided by the lung allocation score (LAS), which takes into account one measure of exercise capacity, the 6-minute walk test (6MWT). There is a paucity of data regarding the role and value of cardiopulmonary stress test (CPET) in the evaluation of lung transplant recipients while on the transplant waiting list and after lung transplantation. While clearly there is a need for further prospective investigation, the available literature strongly suggests a potential role for CPET in the setting of lung transplant.Pulmonary medicine. 01/2012; 2012:237852.