Plozasiran (ARO-APOC3) for Severe Hypertriglyceridemia: The SHASTA-2 Randomized Clinical Trial

Importance

Severe hypertriglyceridemia (sHTG) confers increased risk of atherosclerotic cardiovascular disease (ASCVD), nonalcoholic steatohepatitis, and acute pancreatitis. Despite available treatments, persistent ASCVD and acute pancreatitis-associated morbidity from sHTG remains.

Objective

To determine the tolerability, efficacy, and dose of plozasiran, an APOC3-targeted small interfering-RNA (siRNA) drug, for lowering triglyceride and apolipoprotein C3 (APOC3, regulator of triglyceride metabolism) levels and evaluate its effects on other lipid parameters in patients with sHTG.

Design, Setting, and Participants

The Study to Evaluate ARO-APOC3 in Adults With Severe Hypertriglyceridemia (SHASTA-2) was a placebo-controlled, double-blind, dose-ranging, phase 2b randomized clinical trial enrolling adults with sHTG at 74 centers across the US, Europe, New Zealand, Australia, and Canada from May 31, 2021, to August 31, 2023. Eligible patients had fasting triglyceride levels in the range of 500 to 4000 mg/dL (to convert to millimoles per liter, multiply by 0.0113) while receiving stable lipid-lowering treatment.

Interventions

Participants received 2 subcutaneous doses of plozasiran (10, 25, or 50 mg) or matched placebo on day 1 and at week 12 and were followed up through week 48.

Main Outcomes and Measures

The primary end point evaluated the placebo-subtracted difference in means of percentage triglyceride change at week 24. Mixed-model repeated measures were used for statistical modeling.

Results

Of 229 patients, 226 (mean [SD] age, 55 [11] years; 176 male [78%]) were included in the primary analysis. Baseline mean (SD) triglyceride level was 897 (625) mg/dL and plasma APOC3 level was 32 (16) mg/dL. Plozasiran induced significant dose-dependent placebo-adjusted least squares (LS)-mean reductions in triglyceride levels (primary end point) of -57% (95% CI, -71.9% to -42.1%; P < .001), driven by placebo-adjusted reductions in APOC3 of -77% (95% CI, -89.1% to -65.8%; P < .001) at week 24 with the highest dose. Among plozasiran-treated patients, 144 of 159 (90.6%) achieved a triglyceride level of less than 500 mg/dL. Plozasiran was associated with dose-dependent increases in low-density lipoprotein cholesterol (LDL-C) level, which was significant in patients receiving the highest dose (placebo-adjusted LS-mean increase 60% (95% CI, 31%-89%; P < .001). However, apolipoprotein B (ApoB) levels did not increase, and non-high-density lipoprotein cholesterol (HDL-C) levels decreased significantly at all doses, with a placebo-adjusted change of -20% at the highest dose. There were also significant durable reductions in remnant cholesterol and ApoB48 as well as increases in HDL-C level through week 48. Adverse event rates were similar in plozasiran-treated patients vs placebo. Serious adverse events were mild to moderate, not considered treatment related, and none led to discontinuation or death.

Conclusions and Relevance

In this randomized clinical trial of patients with sHTG, plozasiran decreased triglyceride levels, which fell below the 500 mg/dL threshold of acute pancreatitis risk in most participants. Other triglyceride-related lipoprotein parameters improved. An increase in LDL-C level was observed but with no change in ApoB level and a decrease in non-HDL-C level. The safety profile was generally favorable at all doses. Additional studies will be required to determine whether plozasiran favorably modulates the risk of sHTG-associated complications.

Trial Registration

ClinicalTrials.gov Identifier: NCT04720534.

A First-in-Human Study of AMG 986, a Novel Apelin Receptor Agonist, in Healthy Subjects and Heart Failure Patients

PURPOSE

AMG 986 is a novel apelin receptor (APJ) agonist that improves cardiac contractility in animal models without adversely impacting hemodynamics. This phase 1b study evaluated the safety/tolerability, pharmacokinetics, and pharmacodynamics of AMG 986 in healthy subjects and patients with heart failure (HF).

METHODS

Healthy adults (Parts A/B) and HF patients (Part C) aged 18-85 years were randomized 3:1 to single-dose oral/IV AMG 986 or placebo (Part A); multiple-dose oral/IV AMG 986 or placebo (Part B); or escalating-dose oral AMG 986 or placebo (Part C).

PRIMARY ENDPOINT

treatment-emergent adverse events, laboratory values/vital signs/ECGs; others included AMG 986 pharmacokinetics, left ventricular (LV) function.

RESULTS

Overall, 182 subjects were randomized (AMG 986/healthy: n = 116, placebo, n = 38; AMG 986/HF: n = 20, placebo, n = 8). AMG 986 had acceptable safety profile; no clinically significant dose-related impact on safety parameters up to 650 mg/day was observed. AMG 986 exposures increased nonlinearly with increasing doses; minimal accumulation was observed. In HF with reduced ejection fraction patients, there were numerical increases in percent changes from baseline in LV ejection fraction and stroke volume by volumetric assessment with AMG 986 vs placebo (stroke volume increase not recapitulated by Doppler).

CONCLUSIONS

In healthy subjects and HF patients, short-term AMG 986 treatment was well tolerated. Consistent with this observation, clinically meaningful pharmacodynamic effects in HF patients were not observed. Changes in ejection fraction and stroke volume in HF patients suggest additional studies may be needed to better define the clinical utility and optimal dosing for this molecule.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov NCT03276728.

DATE OF REGISTRATION

September 8, 2017.

Pharmacokinetics, Pharmacodynamics, and Tolerability of Olpasiran in Healthy Japanese and Non-Japanese Participants: Results from a Phase I, Single-dose, Open-label Study

PURPOSE

Olpasiran, an N-acetyl galactosamine-conjugated, hepatocyte-targeted, small interfering RNA, is being developed to reduce plasma lipoprotein (Lp)-(a) concentration by directly targeting the LPA gene. This study evaluated the pharmacokinetics, pharmacodynamics, and tolerability of a single SC injection of olpasiran in healthy, Japanese and non-Japanese participants.

METHODS

In this Phase I, open-label, parallel-design study, Japanese participants were randomized in a 1:1:1:1 ratio to receive a single 3, 9, 75, or 225 mg dose of olpasiran. Non-Japanese participants received a single 75 mg dose of olpasiran. The primary end points were pharmacokinetic parameters, including C_max, AUC_inf, t_max, and t_1/2. Tolerability and change in Lp(a) concentration were also assessed.

FINDINGS

A total of 27 enrolled participants had a mean (SD) age of 48.0 (12.5) years. Olpasiran C_max and AUC_inf were increased in an approximately dose-proportional manner in the Japanese groups. Mean (SD) C_max values were 242 (121.0) and 144 (71.3) ng/mL, and mean (SD) AUC_inf values were 3550 (592.0) and 2620 (917.0) h·ng/mL, in the Japanese and non-Japanese groups, respectively, given 75 mg of olpasiran. Median t_max ranged from 3.0 to 9.0 hours and mean (SD) t_1/2 ranged from 4.0 (0.3) to 6.9 (1.6) hours across all groups. The maximal Lp(a) reduction occurred at day 57, with mean (SD) Lp(a) percentage reductions from baseline ranging from 56.0% (21.0%) to 99.0% (0.2%). A reductions in Lp(a) was observed as early as day 4. All adverse events were mild in severity, with no serious or fatal adverse events. No clinically important changes in tolerability-related laboratory analytes or vital signs were observed.

IMPLICATIONS

In this population of healthy Japanese participants, dose-proportional increases in exposure and reduced Lp(a) in a dose-dependent manner were found with single 3, 9, 75, and 225 mg doses of olpasiran. The magnitude and durability of Lp(a) reductions were similar between the Japanese and non-Japanese groups. Olpasiran was well tolerated, with no clinically important adverse events or laboratory or vital sign abnormalities.

Evaluation of the Pharmacokinetics and Safety of AMG 986 Tablet and Capsule Formulations in Healthy Adult Subjects: A Phase I, Open-Label, Randomized Study

BACKGROUND AND OBJECTIVE

AMG 986 is a first-in-class, novel apelin receptor small molecule agonist initially developed for the treatment of heart failure. The current phase I study was conducted to evaluate the pharmacokinetics and safety of a single-dose 200-mg capsule formulation of AMG 986 relative to the tablet formulation in 12 healthy subjects.

METHODS

In a two-period, two-way crossover design, eligible subjects were randomized 1:1 to tablet/capsule or capsule/tablet treatment sequences; each treatment sequence lasted for approximately 6 days and comprised six subjects.

RESULTS

Following a single oral dose of AMG 986, the geometric mean maximum observed concentration (Cmax) values were 9670 ng/mL and 6920 ng/mL and the geometric mean area under the curve from time zero to 120 h (AUC0-120h) values were 68,000 ng*h/mL and 59,900 ng*h/mL for the tablet and capsule, respectively. The geometric least squares means (90% confidence interval [90% CI]) for the ratios of capsule/tablet were 0.88 (90% CI 0.81-0.96) and 0.72 (90% CI 0.57-0.91) for AUC0-120h and Cmax, respectively. AMG 986 had an acceptable safety profile; all adverse events were grade 1 or 2 in severity.

CONCLUSION

There was a modest 12% decrease in AUC0-120h and a 28% decrease in Cmax with the AMG 986 capsule versus the tablet. These differences are not considered to be clinically relevant, suggesting the capsule formulation can be used in subsequent clinical studies of AMG 986.

A Phase 1, Open-Label Study to Evaluate the Effect of Food and Concomitant Itraconazole Administration on the Pharmacokinetics of AMG 986 in Healthy Subjects

This phase 1, open-label study evaluated the effect of food and administration of the cytochrome P450 3A4 and P-glycoprotein inhibitor itraconazole (ITZ) on the pharmacokinetics of AMG 986. In cohort 1, 12 healthy subjects received a single oral dose of AMG 986 200 mg ± food on days 1 and 10. In cohort 2, 15 healthy subjects received oral ITZ 200 mg once daily on days 8 to 15 and a single oral dose of AMG 986 10 mg on days 1 and 11. The geometric least squares mean ratios of fed/fasted for AMG 986 maximum observed concentration (C_max ) and area under the plasma concentration-time curve from time 0 to infinity (AUC_inf ) were 0.76 (90%CI, 0.61-0.95) and 1.07 (90%CI, 0.94-1.22), respectively. The geometric least squares mean ratios of AMG 986 10 mg plus ITZ 200 mg/AMG 986 10 mg alone for AMG 986 C_max and AUC_inf were 1.36 (90%CI, 1.25-1.48) and 5.13 (90%CI, 4.71-5.59), respectively. Overall, 3 subjects experienced mild treatment-related adverse events; there were no serious or fatal adverse events. In conclusion, food had no apparent effect on the exposure of AMG 986 200 mg; therefore, food restrictions are not required. Potent cytochrome P450 3A4 and/or P-glycoprotein inhibitors may warrant AMG 986 dose reduction and should be coadministered with caution in patients with heart failure treated with AMG 986.

Preclinical development and phase 1 trial of a novel siRNA targeting lipoprotein(a)

Compelling evidence supports a causal role for lipoprotein(a) (Lp(a)) in cardiovascular disease. No pharmacotherapies directly targeting Lp(a) are currently available for clinical use. Here we report the discovery and development of olpasiran, a first-in-class, synthetic, double-stranded, N-acetylgalactosamine-conjugated small interfering RNA (siRNA) designed to directly inhibit LPA messenger RNA translation in hepatocytes and potently reduce plasma Lp(a) concentration. Olpasiran reduced Lp(a) concentrations in transgenic mice and cynomolgus monkeys in a dose-responsive manner, achieving up to over 80% reduction from baseline for 5-8 weeks after administration of a single dose. In a phase 1 dose-escalation trial of olpasiran (ClinicalTrials.gov: NCT03626662 ), the primary outcome was safety and tolerability, and the secondary outcomes were the change in Lp(a) concentrations and olpasiran pharmacokinetic parameters. Participants tolerated single doses of olpasiran well and experienced a 71-97% reduction in Lp(a) concentration with effects persisting for several months after administration of doses of 9 mg or higher. Serum concentrations of olpasiran increased approximately dose proportionally. Collectively, these results validate the approach of using hepatocyte-targeted siRNA to potently lower Lp(a) in individuals with elevated plasma Lp(a) concentration.

A Phase I, Multiple-Dose, Randomized, Double-Blind, Placebo-Controlled Study to Evaluate Pharmacokinetics, Safety, and Tolerability of Etelcalcetide Administered Intravenously to Chinese Patients With Chronic Kidney Disease Undergoing Hemodialysis

PURPOSE

This study reports data from the first evaluation of etelcalcetide treatment in Chinese adults with chronic kidney disease and secondary hyperparathyroidism.

METHODS

This phase I, randomized study compared thrice-weekly etelcalcetide (5 mg per dose intravenously) and placebo in 33 Chinese adults (aged 18-70 years) receiving hemodialysis. Patients in both treatment groups received standard-of-care treatment with a total of 12 doses of the investigational product during a 4-week treatment period, followed by 4 weeks of washout and follow-up. Pharmacokinetic (PK) parameters (primary endpoint), tolerability (secondary endpoint), and changes in intact parathyroid hormone (iPTH) and corrected calcium (cCa) concentrations (exploratory endpoints) were assessed. PK parameters, ie, the maximum plasma concentration (C_max) and area under the plasma concentration-time curve (AUC_0-last), assessed over the interdialytic interval following the first and last doses were evaluated. The incidence of treatment-emergent adverse events (AEs) and anti-etelcalcetide antibodies was assessed.

FINDINGS

Etelcalcetide administered to 25 patients was compared with placebo administered to 8 patients. Etelcalcetide exposure, assessed by C_max and AUC_0-last, increased after multiple-dose administration of etelcalcetide through day 27, with a mean (SD) accumulation ratio of 3.02 (0.61) based on AUC. At least one AE was reported for all patients in the etelcalcetide group and for 87.5% of patients in the placebo group. Serious AEs were reported in 12% of patients in the etelcalcetide group only. No deaths occurred, and a single discontinuation because of patient withdrawal of consent was reported in the etelcalcetide group. Preexisting anti-etelcalcetide antibodies were detected in one patient. The mean serum cCa level for all patients was maintained at >1.75 mmol/L. The iPTH and cCa concentrations decreased as expected, and a maximum mean decrease from baseline of 35.13% in iPTH levels was detected on day 27.

IMPLICATIONS

Multiple doses of 5 mg etelcalcetide were well tolerated, and observed etelcalcetide PK and safety profiles were similar to those in reports in adults of ethnicities other than Chinese. Changes in serum iPTH and serum calcium levels were consistent with expected responses to etelcalcetide. ClinicalTrials.gov identifier: NCT03283098.

Stabilization of Cardiac Function With Diflunisal in Transthyretin (ATTR) Cardiac Amyloidosis

BACKGROUND

Transthyretin amyloidosis cardiomyopathy (ATTR-CM) is an underappreciated cause of heart failure that results from misfolded TTR (prealbumin) protein. Diflunisal is an approved non-steroidal anti-inflammatory drug that stabilizes TTR, with limited data available regarding effects on cardiac structure and function.

METHODS AND RESULTS

ATTR-CM patients (n=81, 41% treated with 250 mg twice-daily diflunisal by clinical practice) were retrospectively identified with baseline and follow-up (median interval 1 year) serum biomarker and echocardiographic data compared, including global longitudinal strain (GLS). Chi-squared and Wilcoxon tests assessed differences between subjects, divided by treatment group, and univariable and multivariable linear regression was performed. At baseline, patients treated with diflunisal were younger (68 vs 77 years, P = .0001), with lower B-type natriuretic peptide (BNP; 249 vs 545 pg/mL, P = .009) and serum creatinine (1.1 vs 1.2 mg/dL, P = .04), but similar TTR concentration (P = .31), cardiac troponin I (P = .06), and GLS (P = .67). At follow-up, diflunisal untreated versus treated patients showed differences in TTR concentration (19 vs 33 mg/dL, P = .01) and favorable differences in left atrial volume index (+4.6 vs -1.4 mL/m², P = .002) and cardiac troponin I (+0.03 vs -0.01 ng/mL, P = .01) for the entire cohort. Among the subset with wild-type ATTR (n=53), diflunisal treatment was associated with differences in GLS (+1.2% untreated vs +0.1% treated, P = .03). Changes in wall thickness (P = .2), left ventricular ejection fraction (P = .71), and BNP (P = .42) were similar between groups.

CONCLUSIONS

In ATTR-CM, diflunisal treatment resulted in measurable differences in some parameters of cardiac structure and function after only 1 year of administration. Further longer-term analysis is warranted.

Reassessing Phase II Heart Failure Clinical Trials: Consensus Recommendations

The increasing burden and the continued suboptimal outcomes for patients with heart failure underlines the importance of continued research to develop novel therapeutics for this disorder. This can only be accomplished with successful translation of basic science discoveries into direct human application through effective clinical trial design and execution that results in a substantially improved clinical course and outcomes. In this respect, phase II clinical trials play a pivotal role in determining which of the multitude of potential basic science discoveries should move to the large and expansive registration trials in humans. A critical examination of the phase II trials in heart failure reveals multiple shortcomings in their concept, design, execution, and interpretation. To further a dialogue on the challenges and potential for improvement and the role of phase II trials in patients with heart failure, the Food and Drug Administration facilitated a meeting on October 17, 2016, represented by clinicians, researchers, industry members, and regulators. This document summarizes the discussion from this meeting and provides key recommendations for future directions.

Magnetic resonance imaging captures the biology of ductal carcinoma in situ

PURPOSE

Magnetic resonance imaging (MRI) is an important tool for characterizing invasive breast cancer but has proven to be more challenging in the setting of ductal carcinoma in situ (DCIS). We investigated whether MRI features of DCIS reflect differences in biology and pathology.

PATIENTS AND METHODS

Forty five of 100 patients with biopsy-proven DCIS who underwent MRI and had sufficient tissue to be characterized by pathologic (nuclear grade, presence of comedo necrosis, size, and density of disease) and immunohistochemical (IHC) findings (proliferation, Ki67; angiogenesis, CD34; and inflammation, CD68). Pathology and MRI features (enhancement patterns, distribution, size, and density) were analyzed using pairwise and canonical correlations.

RESULTS

Histopathologic and IHC variables correlated with MRI features (r = 0.73). The correlation was largely due to size, density (by either MRI or pathology), and inflammation (P < .05). Most small focal masses were estrogen receptor-positive. MRI enhancement patterns that were clumped were more likely than heterogeneous patterns to be high-grade lesions. Homogenous lesions were large, high grade, and rich in macrophages. Presence of comedo necrosis and size could be distinguished on MRI (P < .05). MRI was most likely to over-represent the size of less dense, diffuse DCIS lesions.

CONCLUSION

The heterogeneous presentation of DCIS on MRI reflects underlying histopathologic differences.