some more encouraging results...
HOUSTON, Nov 10, 2000 /PRNewswire via COMTEX/ -- Texas Biotechnology (Amex: TXB) announced that results from two exploratory clinical studies with sitaxsentan, an oral endothelin A receptor antagonist, are being presented at the 73rd Scientific Sessions of the American Heart Association (AHA). These two open-label trials were designed to assess safety and tolerability in two patient populations, essential hypertension and pulmonary hypertension.
In a clinical trial involving 20 patients with pulmonary arterial hypertension, patients experienced statistically significant improvements in both exercise capacity (as assessed by a six minute walk) as well as hemodynamic improvement (decrease in PAP and PVR).
In an essential hypertension trial involving 30 patients with mild to moderate disease, patients treated with sitaxsentan demonstrated statistically significant reductions in blood pressure with no increase in heart rate.
Pulmonary Hypertension Trial -- Dr. Robyn J. Barst, Professor of Pediatrics, Director of New York Presbyterian Hospital Pulmonary Hypertension Center/Columbia University
This open-label study in pulmonary hypertension involved two centers that evaluated 20 patients with primary and secondary pulmonary arterial hypertension (NYHA class II, III and IV). The objective of this study was to assess the safety and tolerability of sitaxsentan administered over a 12-week period.
During the twelve week trial, several efficacy measures were also evaluated. Patients treated with sitaxsentan experienced statistically significant improvements in exercise capacity as assessed by a six minute walk distance. For the 20 patients studied, mean walk time distance improved over 12 weeks by 10.3%, from 466 meters to 514 meters. The p value was highly significant, 0.0062. Statistically significant improvements were also observed in several hemodynamic measures, e.g., mean pulmonary artery
pressure and pulmonary vascular resistance. Quality of life results were inconclusive.
Sitaxsentan was well-tolerated during the 12 week trial. The most frequent adverse events were nasal congestion, abnormal coagulation parameters and flushing. Also observed were headache, edema, nausea, anemia and increased liver function enzyme values. Drug accumulation occurred in all patients. Further analysis of this data is ongoing to better understand the clinical relevance of this finding.
The next step in the development of this investigational agent is to carry out additional studies to establish the optimal dose and the appropriate risk/benefit profile for use of this drug in patients with pulmonary arterial hypertension.
Essential Hypertension Study -- Dr. David A. Calhoun, Medical Director- Vascular Biology and Hypertension Program/University of Alabama - Birmingham
The primary objective of this open label, single center study in 30 patients with mild to moderate hypertension was to compare the safety and tolerability of sitaxsentan at three different dose levels given twice daily for 14 days. This trial also monitored changes in blood pressure, heart rate and plasma endothelin levels. This is the first reported clinical evaluation of a selective endothelin A receptor antagonist in patients with essential hypertension.
Statistically significant reductions in blood pressure were demonstrated at all dose levels compared to baseline values. The drug was well tolerated in this trial with headaches, edema and anemia as the most commonly reported adverse events.
ICOS-Texas Biotechnology L.P.
ICOS-Texas Biotechnology L.P., a partnership between Texas Biotechnology Corporation and ICOS Corporation (Nasdaq: ICOS), are developing selective endothelin A receptor antagonists for the treatment of pulmonary hypertension, essential hypertension and chronic heart failure.
Based on the results from the pulmonary hypertension trial, ICOS-Texas Biotechnology L.P., intends to pursue further clinical studies to assess the safety and efficacy of sitaxsentan as a treatment for pulmonary arterial hypertension, expected to begin in the first quarter of 2001. Discussions to finalize the protocol for the next trial are underway with the U.S. Food & Drug Administration.
Also under development is a second generation selective endothelin A receptor antagonist called TBC3711.
Richard A.F. Dixon, Ph.D., Senior Vice President Research and Chief Scientific Officer at Texas Biotechnology, stated, "The clear clinical response that we have seen with sitaxsentan in several different cardiovascular settings -- chronic heart failure, hypertension and now pulmonary arterial hypertension -- continues to support our confidence in the therapeutic and commercial potential of sitaxsentan and the endothelin receptor antagonist class as a whole."
Texas Biotechnology is a biopharmaceutical company focused on the discovery, development and commercialization of small molecule drugs to treat a variety of vascular diseases including thrombosis, pulmonary hypertension, heart failure and asthma. |
