"In this diverse population of hypercholesterolemic patients, all doses of MK-0616 showed superior reduction of LDL vs placebo up to a 60.9% placebo-adjusted reduction from baseline to week 8, which was consistent across subgroups," Ballantyne reported.
"Reduction in ApoB and non-HDL cholesterol were consistent with that of LDL cholesterol, with up to a 51.8% reduction in ApoB and a 55.8% reduction in non-HDL," he noted.
He added that the drug was well tolerated with no difference in adverse events across the treatment groups compared with placebo.
"These data support the further development of MK-0616, an oral PCSK9 inhibitor that may improve access to effective LDL-cholesterol lowering therapies and improve attainment of guideline-recommended LDL goals aimed at reducing cardiovascular risk," Ballantyne concluded. "The results are encouraging for a phase 3 program that is now being designed."
He explained that elevated LDL is a primary causative factor for atherosclerotic cardiovascular disease (ASCVD), and despite effective treatments (statins), a large proportion of patients fail to achieve guideline-recommended LDL levels. Injectable treatments targeting PCSK9 have demonstrated large reductions in LDL and decreased risk of ASCVD events, but access barriers and need for repeat injections have led to poor adoption. An oral PCSK9 inhibitor may widen access and improve attainment of guideline-recommended treatment goals.
Ballantyne described the new drug, MK-0616, as a "macrocyclic peptide that can bind PCSK9 with monoclonal antibody-like affinity at 1/100th of the molecular weight."
The current phase 2 study included 381 adult patients (49% female; median age 62 years) with a wide range of ASCVD risk. Average LDL-C level was 119.5 mg/dL at baseline. Around 40% of patients were not taking statins, 35% were on low- to moderate-intensity statin therapy, and 26% were on high-intensity statin therapy.
They were randomly assigned to four different doses of MK-0616 (6, 12, 18, or 30 mg once daily) or matching placebo.
Results showed that all doses of MK-0616 demonstrated statistically significant differences in percentage change in LDL-C from baseline to week 8 vs placebo: -41.2% (6 mg), -55.7% (12 mg), -59.1% (18 mg), and -60.9% (30 mg).
The mean percentage change in ApoB from baseline vs placebo were -32.8%, -45.8%, -48.7%, and 51.8% for the four escalating doses of the drug. And non-HDL cholesterol changes were -35.9%, -50.5%, -53.2%, and -55.8% respectively.
The proportion of participants at protocol-defined goals for LDL reduction was 80.5%, 85.5%, 90.8%, and 90.8% with MK-0616 at the 6 mg, 12 mg, 18 mg, and 30 mg doses, compared with 9.3% with placebo.
Ballantyne reported that the efficacy looked similar in all subgroups, and regardless of baseline therapy.
"This was a dose-finding study, which will help select a dose to be taken forward in larger studies, and it looks from these results as though you get most of the efficacy by 12 mg," he added.
Adverse events occurred in a similar proportion of participants in the MK-0616 groups (39.5% to 43.4%) as placebo (44.0%), and discontinuations as a result of adverse events occurred in two or fewer participants in any treatment group.