Positioning imatinib for pulmonary arterial hypertension: A phase I/II design comprising dose finding and single-arm efficacy.


Type
Article
Change log
Authors
Mckie, Mikel A 
Roussakis, Andreas A  ORCID logo  https://orcid.org/0000-0001-5748-6978
Harbaum, Lars 
Abstract

Pulmonary arterial hypertension is an unmet clinical need. Imatinib, a tyrosine kinase inhibitor, 200 to 400 mg daily reduces pulmonary artery pressure and increases functional capacity in this patient group, but is generally poorly tolerated at the higher dose. We have designed an open-label, single-arm clinical study to investigate whether there is a tolerated dose of imatinib that can be better targeted to patients who will benefit. The study consists of two parts. Part 1 seeks to identify the best tolerated dose of Imatinib in the range from 100 and up to 400 mg using a Bayesian Continuous Reassessment Method. Part 2 will measure efficacy after 24 weeks treatment with the best tolerated dose using a Simon's two-stage design. The primary efficacy endpoint is a binary variable. For patients with a baseline pulmonary vascular resistance (PVR) >1000 dynes · s · cm-5, success is defined by an absolute reduction in PVR of ≥300 dynes · s · cm-5 at 24 weeks. For patients with a baseline PVR ≤1000 dynes · s · cm-5, success is a 30% reduction in PVR at 24 weeks. PVR will also be evaluated as a continuous variable by genotype as an exploratory analysis. Evaluating the response to that dose by genotype may inform a prospective biomarker-driven study.

Description
Keywords
Adaptive design, efficacy, safety, tolerability
Journal Title
Pulm Circ
Conference Name
Journal ISSN
2045-8932
2045-8940
Volume Title
11
Publisher
Wiley
Sponsorship
Medical Research Council (MC_UU_00002/15)
Efficacy and Mechanism Evaluation Programme (NIHR128465)
National Institute for Health Research (NIHR) (NIHR128465)
British Heart Foundation (RE/18/4/34215)