Ionis Pharmaceuticals announced that biopharmaceutical company AstraZeneca has initiated a Phase 2b clinical trial of ION449 (AZD8233), an investigational antisense medicine designed to reduce blood cholesterol levels in patients with dyslipidemia by targeting proprotein convertase subtilisin/kexin type 9 (PCSK9), an important regulator of low-density lipoprotein cholesterol (LDL-C). PCSK9 is an enzyme that controls the number of LDL receptors on the surface of cells. People with genetic variations that reduce PCSK9 function have lower LDL-C levels in the blood and a lower risk for major cardiovascular events. ION449 is a LIgand Conjugated Antisense (LICA) medicine being developed by AstraZeneca as part of a collaboration between Ionis and AstraZeneca.

The Phase 2b, randomized, double-blind, placebo-controlled trial will enroll approximately 108 participants, aged 18-75, who have LDL-C levels between 70 and 190 mg/dL and are receiving moderate- or high-intensity statin therapy as defined by the American College of Cardiology/American Heart Association (ACC/AHA) guidelines on blood cholesterol management. The primary objective is to assess the effect of different doses of ION449 on LDL-C compared to placebo at Week 12 in patients taking baseline statin therapy. The study will evaluate three dose levels of ION449 versus placebo, all administered once a month by subcutaneous injection.

In a Phase 1 study reported at the American Heart Association (AHA) Scientific Sessions on November 13, single subcutaneous doses of ION449 (AZD8233) demonstrated dose-dependent mean reductions in circulating plasma PCSK9 and LDL-C levels of >90 percent and up to 70 percent, respectively, in subjects who had a baseline LDL-C between 100 and 190 mg/dL without concomitant statin therapy. Doses up to 120 mg were evaluated. ION449 was observed to be safe and well-tolerated at all dose levels.

"Results from the Phase 1 study showed that ION449 potently reduces PCSK9 and LDL cholesterol. ION449 demonstrated best-in-class potential for PCSK9 inhibition and LDL-C reduction, supporting larger clinical trials that are now underway to further evaluate efficacy and safety," said Sotirios "Sam" Tsimikas, M.D., senior vice president, clinical development and cardiovascular franchise leader at Ionis. "The growing evidence supporting Ionis' advanced LICA technology in cardiovascular disease holds promise for more effective approaches to lower LDL-C and to address cardiovascular disease, the leading cause of death worldwide."

Ionis earned a milestone payment of $20 million from AstraZeneca for the Phase 2b clinical trial initiation of ION449. Ionis and AstraZeneca are collaborating on potential treatments for kidney disease, cardiometabolic disease and cancer.