The annual rate of aSAH in United States is approximately 18 to 24 thousand cases each year. Mortality rates following aSAH range from 30-70% with 10-20% of survivors experiencing severe neurological disability. Following aSAH, a major cause of morbidity and mortality is vasospasm, which causes delayed ischemic neurologic deterioration. There is currently no effective treatment for preventing or ameliorating the damage that occurs following cerebral ischemia. A myriad of neuro-toxins are produced in the ischemic brain resulting in a vicious cycle of cellular death and destruction. The polyamines spermine and spermidine are metabolized by polyamine oxidase (PAO) into putrescine and 3-aminopropanal (3AP).
Tiopronin (Thiola) is an FDA approved drug used for the treatment of cystine stones in patients with cystinuria in the U.S. In Europe, it is also used for the treatment of rheumatoid arthritis and bronchial hypersecretion. In previous animal studies, we demonstrated that tiopronin is able to bind and neutralize the toxic effects of 3AP. We have shown in previous studies that aSAH patients have elevated 3AP levels, and higher levels correlate to a poor neurologic outcome.
The goals of this phase II multicenter, randomized, double-blinded safety and efficacy trial are to (1) further evaluate the safety of the drug in our patient population at the dose established in phase I; (2) demonstrate that tiopronin crosses the blood-brain barrier; (3) show that both serum and CSF 3AP levels are reduced by administration of tiopronin; and (4) demonstrate that a reduction in 3AP levels is associated with improved neurologic outcome in aSAH patients.
