Phase I trial and pharmacokinetic study of berubicin (RTA 744) in patients with recurrent or refractory high-grade gliomas.

BACKGROUND: This multi-institutional phase I trial aimed to determine the maximum tolerated dose (MTD), dose-limiting toxicities, pharmacokinetics, and preliminary antitumor activity of berubicin (WP744 or RTA744), designed to cross the blood-brain barrier, in patients with primary brain cancers. METHODS: Thirty-five patients with recurrent or refractory primary brain cancers, including glioblastoma multiforme, received berubicin infusions over 2 h for 3 consecutive days (one course) every 21 days. Daily doses escalated from 1.2 to 9.6 mg/m2 using an accelerated titration design. Plasma levels of berubicin were measured via high-performance liquid chromatography-tandem mass spectrometry to estimate pharmacokinetic parameters. RESULTS: The daily MTD was determined to be 7.5 mg/m2. Nonhematological toxicities were minimal; no cardiotoxicity was observed. In the intention-to-treat population (n = 35), 1 patient had a durable complete response, 1 had a partial response, and 9 had stable disease, corresponding to an objective response rate of 5.7% and a disease control rate of 31.4%. In the response-evaluable subset (n = 25), the corresponding rates were 8% and 44%, respectively; these secondary estimates should be interpreted with caution as patients who discontinued early were excluded. Pharmacokinetic analysis determined a mean half-life of 32.8 h. The area under the curve increased proportionally with dose. CONCLUSIONS: The tolerability and efficacy of berubicin, including one durable complete response, warrant continued development of the molecule. Berubicin shows activity over a range of doses, including a durable response at 2.4 mg/m2. The recommended phase II dose is 7.5 mg/m2 infusions over 2 h for 3 days every 3 weeks. TRIAL REGISTRATION: NCT00526812.