21.   Many have seen promising drugs reach the end of development, only to fail in some final study.

22.   Many such collaborations involved research into probing the human genetic makeup in the pursuit of promising drugs.

23.   More than a few promising drugs have shown serious problems once they became widely prescribed.

24.   Narayan, who studies patients with severe head injuries, agreed with Fost that patients would want to receive promising experimental drugs.

25.   Often it takes them years to synthesize a version of a promising drug that does what it is supposed to do.

26.   Other researchers still labor to find better ways to test promising drugs in animals.

27.   Over the past several years, the agency has allowed some particularly promising drugs to win approval without going through the normal battery of tests.

28.   Others have acquired promising drugs or bought companies to get access to near-term drug candidates.

29.   Schering has several promising drugs in its research pipeline, which could eventually help offset a decline in Claritin sales.

30.   Searle has several promising drugs on the market or in testing, including arthritis and inflammation treatments.