PHASE-I CLINICAL-TRIALS OF MRX-115 - A NEW ULTRASOUND CONTRAST AGENT

RATIONALE AND OBJECTIVES. Stabilized microbubbles are under developmen t as contrast agents for medical ultrasound, The authors report the re sults of Phase I clinical trials of a new ultrasound contrast agent ba sed on lipid-encapsulated perfluorocarbon gas microbubbles. METHODS. L ipids encapsulating perfluoropropane gas (Aerosomes(R) MRX-115, ImaRx Pharmaceutical Corp., Tucson, AZ) were evaluated in Phase I clinical t rials, Two separate studies mere performed, The first was a single esc alating-dose study (n = 30 subjects), and the second was a multiple-do se study (n = 18 subjects) with rechallenge in several subjects (n = 4 ) after 21 days, Echocardiographic examinations were performed before and after contrast agent for each test drug administration for both st udies, with the exception of the rechallenge group, Doses tested in th e single-dose study ranged from 0.005 mL/kg to 0.100 mL/kg body weight , In the multiple-dose study, five doses of 0.005 mL/kg to 0.030 mL/kg (0.025-0.150 mL/kg total dose) were evaluated, Studies were single-ma sked, placebo-controlled, and safety assessment and adverse events wer e monitored, RESULTS. All doses in both studies were well tolerated wi th no treatment-related changes in safety measures for either study, L eft ventricular cavity and myocardial enhancement were seen with all d oses of MRX-115, CONCLUSIONS. MRX-115 is a promising new intravascular ultrasound contrast agent that was safe and well tolerated at the dos es evaluated in these studies.