UPDATE 1-AstraZeneca buys early-stage U.S. biotech firm

* MedImmune unit acquires private company AlphaCore Pharma

* AlphaCore focused on new approach to managing cholesterol

* Financial details of acquisition not disclosed

LONDON, April 3 (Reuters) - AstraZeneca boosted its early-stage pipeline of experimental heart drugs on Wednesday by buying privately held U.S. biotechnology company AlphaCore Pharma, which is developing a new type of cholesterol medicine.

Financial details of the acquisition by the British drugmaker's MedImmune unit were not disclosed.

AstraZeneca's new CEO Pascal Soriot said last month he planned to build up the company's sparse drug pipeline by striking more deals, with cardiovascular and metabolic disease a particular priority.

Cardiovascular and metabolic disease is one of three core therapy areas for AstraZeneca - along with oncology and respiratory/inflammation - but the company currently has few experimental compounds for such conditions.

AlphaCore will help plug the gap, although it will not deliver any marketable products for many years. Its leading drug candidate ACP-501, a genetically engineered liver-derived enzyme called LCAT, only completed Phase I clinical tests last year.

Drugs need to go through three phases of lengthy tests before being approved for sale.

The hope is that ACP-501 will help in the management of cholesterol to reduce the risk of heart attacks and strokes. It could also play a role in a rare, hereditary disorder called familial LCAT deficiency in which the LCAT enzyme is absent.

"As the science in this area continues to evolve, we are committed to exploring unique pathways that could lead to new combination or standalone therapies for patients living with chronic and acute cardiovascular diseases," said MedImmune head Bahija Jallal.