Lantheus Medical Imaging is touting a phase III study of its flurpiridaz F-18 investigational PET agent for myocardial perfusion imaging (MPI), with data presented at the International Conference on Nuclear Cardiology and Cardiac CT (ICNC12) in Madrid.
The multicenter, international study enrolled 795 subjects with known or suspected coronary artery disease (CAD) who were scheduled for coronary angiography and SPECT imaging. Subjects underwent flurpiridaz F-18 PET MPI and SPECT MPI, with coronary angiography used as the standard for each. Flurpiridaz F-18 has a 110-minute half-life, making it easy to use with treadmill exercise stress testing, according to the company.
Flurpiridaz F-18 imaging demonstrated high sensitivity and specificity when compared with coronary angiography, while SPECT demonstrated low sensitivity and high specificity. Flurpiridaz F-18 exceeded SPECT for sensitivity but did not meet the noninferiority threshold for specificity, implying an underdiagnosis of CAD with SPECT imaging in the trial, Lantheus said.
The study also compared the diagnostic accuracy of flurpiridaz F-18 versus SPECT imaging, showing statistical significance in the overall population and in populations of special clinical interest, including women and obese subjects. The agent's superiority over SPECT for diagnostic accuracy in area under the receiver operator characteristics (ROC) curve analysis was particularly seen in women, obese subjects, and those with multivessel disease.
Flurpiridaz F-18 also reduced radiation dose by approximately 50%, compared with SPECT MPI, Lantheus noted.
Based on the results of the study, the company redesigned the protocol for its second phase III study to include different primary end points -- namely, the performance of flurpiridaz F-18 on its own instead of corroborating with coronary angiography. The U.S. Food and Drug Administration (FDA) has granted a special protocol assessment in connection with the new study, and Lantheus is in discussions with prospective partners for further development and commercialization of the agent, the firm said.
