CHICAGO, March 30 (Reuters) - The highest dose of an

experimental drug developed by Eli Lilly ( LLY ) significantly

reduced levels of a genetically inherited risk factor for heart

disease in a midstage trial, according to data presented at a

major medical meeting on Sunday.

The drug, lepodisiran, reduced levels of lipoprotein(a), or

Lp(a), by an average of 93.9% versus placebo over six months

after a single 400 milligram dose. There were 72 patients in the

400 mg arm of the study, while 69 received a placebo.

After a second 400 mg dose given at six months, participants

saw an average reduction of nearly 95% over 12 months.

No serious adverse events related to the drug were reported.

"What we have is a drug that can lower lipoprotein(a) with

very infrequent administration," study author Dr. Steven Nissen,

a long-time cardiologist at the Cleveland Clinic, said in an

interview. Nissen presented the results at the American College

of Cardiology meeting in Chicago. They were also published in

the New England Journal of Medicine.

Lilly's drug is one of several being tested to treat high

Lp(a), a risk factor for heart disease that affects an estimated

1.4 billion people worldwide, including 64 million people in the

United States.

Unlike LDL, the so-called bad cholesterol that can be

treated with diet and statins, there are no approved treatments

for Lp(a), and few individuals even know they have it.

Elevated Lp(a) can significantly increase the risk of heart

attack, stroke, narrowing of the aortic valve, and peripheral

artery disease, a buildup of fatty plaques in the arteries.

Individuals of African ancestry are at highest risk.

Lilly has already moved lepodisiran into late-stage clinical

trials.

While the drug reduced a cardiovascular risk factor, large

trials are needed to prove that lowering Lp(a) actually cuts

heart attacks and other adverse cardiovascular events, Nissen

said.

Lilly is conducting a second Phase 3 trial to test whether

lowering Lp(a) actually reduces those risks. Nissen said patient

enrollment in that trial should be completed this year.

Other injectable treatments for Lp(a) in development include

Silence Therapeutics' ( SLN ) zerlasiran, Amgen's ( AMGN )

olpasiran and pelacarsen from Novartis.

Lilly is also testing muvalaplin, the only oral treatment

for LP(a) in clinical trials.

Merck ( MRK ) last week signed a licensing agreement with

Jiangsu Hengrui Pharmaceuticals to test its

experimental Lp(a) pill called HRS-5346.