By Randall Osborne
After a setback with a different drug earlier this year, Texas Biotechnology Corp. (TBC) said preliminary data is encouraging from the second half of a Phase II trial with the intravenous formulation of the company's treatment for congestive heart failure.
Protocol for another Phase II trial is being established and an investigational new drug application for an oral formulation of the compound will be filed soon, said David McWilliams, president and CEO of Houston-based TBC.
"It will probably be done this summer," he said.
The first half of the 48-patient trial, reported in February, ended early due to statistically significant interim results. TBC amended the protocol to allow further evaluation at a higher dose. (See BioWorld Today, Feb. 12, 1998, p. 3.)
Now the drug, endothelin A receptor antagonist TBC11251, has shown similarly encouraging results in the primary endpoint of improving central hemodynamics, pulmonary vascular resistance in particular.
TBC11251 is the first such compound to demonstrate efficacy in heart failure patients. If it succeeds, it will provide a complement to the standard therapy of angiotensin-converting enzyme (ACE) inhibitors.
ACE inhibitors work on the left side of the heart, while the company's endothelin blocker is designed to relieve pressure on the right side.
"We're anticipating some synergistic effects," McWilliams said.
For the next trial, TBC is deciding about duration and whether all patients will be taking ACE inhibitors.
"In the first two studies, the patients were off therapy," McWilliams said.
In May, the FDA sent TBC a "not aprovable" letter related to its new drug application for Novastan, an anticoagulant that inhibits the enzyme thrombin. (See BioWorld Today, May 12, 1998, p. 1.)
"We're hoping to turn that around," McWilliams told BioWorld Today.
Novastan is under development with marketing partner SmithKline Beecham plc, of London.
"We have a very good plan for resubmission in place, which has been mostly crafted by SmithKline," McWilliams said.
TBC's stock (AMEX:TXB) closed Thursday at $5.187, down $0.062. *