PK Data from Drug-Drug Interaction Study Describes Lack of CYP3A4 Interactions
BERLIN, June 28, 2013 (GLOBE NEWSWIRE) -- TESARO, Inc. (Nasdaq:TSRO), an oncology-focused biopharmaceutical company, today announced that results from a pharmacokinetic study of rolapitant, an NK-1 receptor antagonist, were presented this morning at the Multinational Association of Supportive Care in Cancer/International Society of Oral Oncology (MASCC/ISOO) International Symposium in Berlin. These data support that rolapitant may be administered concomitantly with other pharmaceutical products that are metabolized by the liver microsomal enzyme CYP3A4, without a requirement for dose adjustment of the co-administered product. Pharmacokinetic data for other NK-1 receptor antagonists indicate that doses of concomitantly administered products metabolized by CYP3A4 must often be adjusted. "We are pleased that these data contribute to a potential best-in-class profile for rolapitant, and believe that its long half life, potential to prevent significant nausea, and planned availability in both oral and intravenous formulations may help to differentiate it from competing agents," said Mary Lynne Hedley, Ph.D., President of TESARO. An open-label drug-drug interaction study was conducted in 26 healthy subjects to evaluate the need for potential dose adjustments of drugs metabolized by cytochrome P450 3A4 (CYP3A4) that might be co-administered with rolapitant. Participants in this study received oral doses of midazolam, a sensitive CYP3A4 substrate, on Days 1, 3, 8 and 11 of the study, and received a single oral 200 milligram dose of rolapitant on Day 3. Serial blood samples were collected to enable measurement and comparisons of plasma levels of midazolam and its metabolite, 1-OH midazolam, over time. Results demonstrated that administration of rolapitant had no effect on midazolam or 1-OH midazolam pharmacokinetics at any measured time point, including on Day 3, when rolapitant plasma levels reached peak concentrations. In addition, SCH 720881, the active metabolite of rolapitant, did not alter plasma levels of midazolam. Taken together, these results suggest that neither rolapitant, nor its active metabolite, are inhibitors or inducers of CYP3A4, the major isozyme involved in drug metabolism. Single oral doses of 200 milligrams of rolapitant were safe and well tolerated.