* Amgen anti-PCSK9 drug slashes LDL in healthy volunteers
* Patients followed for 85 to 113 days after one injection
* Data come on heels of favorable Regeneron studies
By Ransdell Pierson
Nov 14 (Reuters) - A potentially powerful new approach to lower cholesterol by blocking a protein called PCSK9 gained ground, as a new drug from Amgen Inc cut levels of "bad" LDL cholesterol by almost two-thirds in a small study.
The world's largest biotechnology company on Monday presented data from the early stage trial that showed the highest dose of its treatment AMG145 cut LDL levels 64 percent in healthy volunteers, compared with a placebo injection.
The study, whose results were presented at the annual scientific meeting of the American Heart Association in Orlando, involved 54 men and two women -- 18 to 45 years old -- who were healthy and not taking other medications.
They received a single injection that contained one of five doses of AMG145, or a placebo, and their cholesterol was measured frequently for 85 to 113 days.
"The more PCSK9 was lowered, the more bad cholesterol levels went down," said Clapton Dias, a senior Amgen research executive who led the study. "With higher doses, bad cholesterol stayed lower for a longer period."
Amgen said it is now conducting a similar study among adults who are already taking standard treatments called statins to control their cholesterol.
The California-based company is among a growing number of drugmakers that are racing to develop medicines that block PCSK9.
U.S. biotechnology company Regeneron and its French pharmaceutical partner Sanofi are way out front, with plans to soon begin late-stage studies of their injectable product REGN727.
The companies last week said their drug, when given at varying doses in combination with statins, further reduced LDL levels 30 percent to more than 65 percent. The patients have familial hypercholesterolemia, an inherited condition associated with very high LDL levels.
Other companies testing anti-PCSK9 medicines include Pfizer , Merck & Co , Alnylam Pharmaceuticals and a partnership between Bristol-Myers Squibb and Isis Pharmaceuticals .
The products, if approved, are expected to be used alongside statins, such as Pfizer's Lipitor and AstraZeneca's Crestor, for patients who do not achieve cholesterol-lowering goals with statins alone.
They would also be used on their own for a much smaller group who cannot tolerate statins -- oral drugs with global annual sales of $20 billion that inhibit the liver's production of LDL cholesterol.