Texas ET A Blocker Starts Trials For CHF

Texas Biotechnology has started a Phase I trial in the UK of TBC 11251, a small-molecule endothelin (ET) A receptor antagonist, for the treatment of congestive heart failure. It is one of the first drugs in this class to be advanced into the clinic.

Endothelin-1 levels are known to be elevated in patients with heart failure, and the factor has potent vasoconstrictor and positive inotropic properties which may contribute to the progression of the disease. It has been hypothesized that selective inhibition of the ET A receptor may be the best option for vasodilator therapy in HF, (decreasing the workload of the failing heart) as ET B receptors may mediate vasodilation to a greater extent. Indeed, non-selective ET receptor blockers have generally been found to be less effective vasodilators than ET A-selective agents.

TBC president and chief executive David McWilliams noted that TBC 11251 is the company's first in-house-developed product to reach clinical trials. "We plan to file an Investigational New Drug application by the end of 1996 to begin additional clinical trials in the USA," he said.