There was something funny about the ambrisenten data
The population of that trial seems to act differently than other drugs and even Myogen's phase 2 trial
I am not so sure that the next trial will have the results that this recent trial did.
Myogen also eliminated people with connective tissue disease from this trial. Those people don't do as well as the rest of the population with the endothelin antagonists.
Encysive included those patients in their trials. Does that mean ambrisenten should be excluded for that population if it does get approved?
DENVER, May 23 /PRNewswire-FirstCall/ -- Myogen, Inc. (Nasdaq: MYOG), a
biopharmaceutical company focused on the discovery, development and
commercialization of small molecule therapeutics for the treatment of
cardiovascular disorders, today announced that two abstracts describing the
effects of ambrisentan in patients with pulmonary arterial hypertension (PAH)
were presented at ATS 2005 - San Diego, the annual International Conference of
the American Thoracic Society. These abstracts summarize additional results
from the Phase 2 study of ambrisentan in 64 patients with PAH (AMB-220) and
the subsequent open-label long-term study (AMB-220-E). One-year follow-up
safety and efficacy results, as well as comparable effects of ambrisentan in
WHO functional Class II and Class III PAH patients, were presented.
On Sunday, May 22, 2005, Adaani E. Frost, M.D., presented "Ambrisentan
Improves 6-Minute Walk Distance Comparably for WHO Class II and III PAH
Patients." Dr. Frost is Professor of Medicine at Baylor University and a
principal investigator for AMB-220. This abstract reported on the relative
efficacy observed for ambrisentan following treatment in patients classified
as having WHO Class II symptoms at the start of treatment versus those
classified with WHO Class III symptoms. Of the 64 patients enrolled in the
study, 23 patients had WHO Class II symptoms and 41 patients had WHO Class III
symptoms. The mean baseline six-minute walk distance for these two groups of
patients were substantially different: the patients with Class II symptoms
had a mean six-minute walk distance at baseline of 390 meters and the patients
with Class III symptoms had a mean six-minute walk distance at baseline of
316 meters. The data showed that both patient populations benefited equally
in their improvement in six-minute walk distance at 12 weeks (37.7 meters for
patients with Class II symptoms and 35.2 meters for patients with Class III
symptoms) and at 24 weeks (58.3 meters for patients with Class II symptoms and
51.9 meters for patients with Class III symptoms). There were no
statistically significant differences between the two groups in the change
from baseline at either time point.
Improvements in six-minute walk distance at week 12 and week 24 were
accompanied with sustained or improved levels of dyspnea (or breathlessness)
compared to baseline for both classes. Class III patients had a significant
improvement from baseline in dyspnea following exercise at week 12 and
week 24, while Class II patients maintained a similar level of dyspnea
compared to baseline, even though they were walking substantially further in
the six-minute walk test. The improvements in Borg dyspnea index between the
two groups were significantly greater for the Class III patients at week 24,
but not at week 12.
