Credit: FDA
The US Food and Drug Administration (FDA) has granted orphan designation for the histone deacetylase (HDAC) inhibitor pracinostat to treat acute myeloid leukemia (AML) and the proteasome inhibitor marizomib to treat multiple myeloma (MM).
Orphan designation is available for drugs that treat or prevent rare diseases affecting fewer than 200,000 people in the US.
The designation qualifies the sponsor of a drug for development incentives, including tax credits for qualified clinical testing, prescription drug user fee exemptions, and 7-year marketing exclusivity upon FDA approval.
About pracinostat
The oral HDAC inhibitor pracinostat has been tested in phase 1 and 2 trials of adult and pediatric patients with advanced hematologic disorders and solid tumors.
The drug has been generally well tolerated in more than 200 patients to date, according to the drug’s maker, MEI Pharma.
In a dose-escalation phase 1 trial, pracinostat demonstrated single-agent activity in elderly AML patients. Two of 14 patients (14%) achieved a complete remission, with responses persisting more than 206 days and 362 days.
Researchers are currently conducting a phase 2 trial of pracinostat in combination with azacitidine in elderly patients with newly diagnosed AML. Preliminary data from this trial are expected to be available by December 2014.
About marizomib
The proteasome inhibitor marizomib is under development for the treatment of MM and other malignancies.
Intravenous marizomib has been evaluated in more than 230 patients across 4 phase 1/2 studies, as a single agent or in combination with dexamethasone or an HDAC inhibitor.
Researchers are currently evaluating marizomib in combination with dexamethasone in an ongoing phase 2 trial of highly refractory MM patients, including those who are refractory to carfilzomib.
Marizomib is also being tested in combination with pomalidomide and dexamethasone in a phase 1/2 study of patients with relapsed and refractory MM.
The drug’s maker, Triphase Accelerator Corporation, is currently developing an oral formulation of marizomib.
