Homeostatic plasticity in the retina is associated with maintenance of night vision during retinal degenerative disease.

Neuronal plasticity of the inner retina has been observed in response to photoreceptor degeneration. Typically, this phenomenon has been considered maladaptive and may preclude vision restoration in the blind. However, several recent studies utilizing triggered photoreceptor ablation have shown adaptive responses in bipolar cells expected to support normal vision. Whether such homeostatic plasticity occurs during progressive photoreceptor degenerative disease to help maintain normal visual behavior is unknown. We addressed this issue in an established mouse model of Retinitis Pigmentosa caused by the P23H mutation in rhodopsin. We show robust modulation of the retinal transcriptomic network, reminiscent of the neurodevelopmental state, and potentiation of rod - rod bipolar cell signaling following rod photoreceptor degeneration. Additionally, we found highly sensitive night vision in P23H mice even when more than half of the rod photoreceptors were lost. These results suggest retinal adaptation leading to persistent visual function during photoreceptor degenerative disease.

IONIS-PKKRx a Novel Antisense Inhibitor of Prekallikrein and Bradykinin Production.

Kallikrein is the key contact system mediator responsible for the conversion of high-molecular-weight kininogen into the inflammatory vasodilator peptide bradykinin, a process regulated by C1-esterase inhibitor (C1-INH). In hereditary angioedema (HAE), genetic mutations result in deficient or dysfunctional C1-INH and dysregulation of the contact system leading to recurrent, sometimes fatal, angioedema attacks. IONIS-PKKRx is a second-generation 2'-O-(2-methoxyethyl)-modified chimeric antisense oligonucleotide, designed to bind and selectively reduce prekallikrein (PKK) mRNA in the liver. IONIS-PKKRx demonstrated dose-dependent reduction of human prekallikrein hepatic mRNA and plasma protein in transgenic mice and dose- and time-dependent reductions of plasma PKK in Cynomolgus monkeys. Similar dose-dependent reductions of plasma PKK levels were observed in healthy human volunteers accompanied by decreases in bradykinin generation capacity with an acceptable safety and tolerability profile. These results highlight a novel and specific approach to target PKK for the treatment of HAE and other diseases involving contact system activation and overproduction of bradykinin.

Antisense Inhibition of Glucagon Receptor by IONIS-GCGRRx Improves Type 2 Diabetes Without Increase in Hepatic Glycogen Content in Patients With Type 2 Diabetes on Stable Metformin Therapy.

OBJECTIVE: To evaluate the safety and efficacy of IONIS-GCGRRx, a 2'-O-methoxyethyl antisense oligonucleotide targeting the glucagon receptor (GCGR), and the underlying mechanism of liver transaminase increases in patients with type 2 diabetes on stable metformin therapy. RESEARCH DESIGN AND METHODS: In three phase 2, randomized, double-blind studies, patients with type 2 diabetes on metformin received weekly subcutaneous injections of IONIS-GCGRRx (50-200 mg) or placebo for 13 or 26 weeks. RESULTS: Significant reductions in HbA1c were observed after IONIS-GCGRRx treatment versus placebo at week 14 (-2.0% 200 mg, -1.4% 100 mg, -0.3% placebo; P < 0.001) or week 27 (-1.6% 75 mg, -0.9% 50 mg, -0.2% placebo; P < 0.001). Dose-dependent increases in transaminases were observed with IONIS-GCGRRx, which were attenuated at lower doses and remained mostly within the normal reference range at the 50-mg dose. There were no other significant safety observations and no symptomatic hypoglycemia or clinically relevant changes in blood pressure, LDL cholesterol, or other vital signs. At week 14, IONIS-GCGRRx 100 mg did not significantly affect mean hepatic glycogen content compared with placebo (15.1 vs. -20.2 mmol/L, respectively; P = 0.093) but significantly increased hepatic lipid content (4.2 vs. -2.7%, respectively; P = 0.005) in the presence of transaminase increases. CONCLUSIONS: IONIS-GCGRRx is a potent inhibitor of hepatic glucagon receptor expression with a potential to improve glycemic control at low weekly doses in combination with metformin. Significant reductions in HbA1c occurred across the full-dose range tested, with minimal transaminase elevations at lower doses. Furthermore, novel results suggest that despite inhibition of glycogenolysis after GCGR antagonism, IONIS-GCGRRx did not increase hepatic glycogen content.

Antisense Inhibition of Protein Tyrosine Phosphatase 1B With IONIS-PTP-1BRx Improves Insulin Sensitivity and Reduces Weight in Overweight Patients With Type 2 Diabetes.

OBJECTIVE: To evaluate safety and efficacy of IONIS-PTP-1BRx, a second-generation 2'-O-methoxyethyl antisense inhibitor of protein tyrosine phosphatase 1B, as add-on therapy in overweight patients with type 2 diabetes inadequately controlled with metformin with or without sulfonylurea therapy. RESEARCH DESIGN AND METHODS: In this phase II, double-blind, randomized, placebo-controlled, multicenter trial, overweight and obese patients (BMI ≥27 kg/m2) with type 2 diabetes (HbA1c ≥7.5% [58 mmol/mol] and ≤10.5% [91 mmol/mol]) on a stable dose of metformin alone or with sulfonylurea were randomized 2:1 to IONIS-PTP-1BRx 200 mg (n = 62) or placebo (n = 30) once weekly for 26 weeks. RESULTS: Mean baseline HbA1c was 8.6% (70 mmol/mol) and 8.7% (72 mmol/mol) in placebo and active treatment, respectively. At week 27, IONIS-PTP-1BRx reduced mean HbA1c levels by -0.44% (-4.8 mmol/mol; P = 0.074) from baseline and improved leptin (-4.4 ng/mL; P = 0.007) and adiponectin (0.99 µg/mL; P = 0.026) levels compared with placebo. By week 36, mean HbA1c was significantly reduced (-0.69% [-7.5 mmol/mol]; P = 0.034) and accompanied by reductions in fructosamine (-33.2 µmol/L; P = 0.005) and glycated albumin (-1.6%; P = 0.031) versus placebo. Despite both treatment groups receiving similar lifestyle counseling, mean body weight significantly decreased from baseline to week 27 with IONIS-PTP-1BRx versus placebo (-2.6 kg; P = 0.002) independent of HbA1c reduction (R2 = 0.0020). No safety concerns were identified in the study. CONCLUSIONS: Compared with placebo, IONIS-PTP-1BRx treatment for 26 weeks produced prolonged reductions in HbA1c, improved medium-term glycemic parameters, reduced leptin and increased adiponectin levels, and resulted in a distinct body weight-reducing effect.

The Effects of 2'-O-Methoxyethyl Oligonucleotides on Renal Function in Humans.

Systemically administered 2'-O-methoxyethyl (2'MOE) antisense oligonucleotides (ASOs) accumulate in the kidney and metabolites are cleared in urine. The effects of eleven 2'MOE ASOs on renal function were assessed in 2,435 patients from 32 phase 2 and phase 3 trials. The principle analysis was on data from 28 randomized placebo-controlled trials. Mean levels of renal parameters remained within normal ranges over time across dose groups. Patient-level meta-analyses demonstrated a significant difference between placebo-treated and 2'MOE ASO-treated patients at doses >175 mg/week in the percentage and absolute change from baseline for serum creatinine and estimated glomerular filtration rate. However, these changes were not clinically significant or progressive. No dose-related effects were observed in the incidence of abnormal renal test results in the total population of patients, or subpopulation of diabetic patients or patients with renal dysfunction at baseline. The incidence of acute kidney injury [serum creatinine ≥0.3 mg/dL (26.5 µM) increases from baseline or ≥1.5 × baseline] in 2'MOE ASO-treated patients (2.4%) was not statistically different from placebo (1.7%, P = 0.411). In conclusion, in this database, encompassing 32 clinical trials and 11 different 2'MOE ASOs, we found no evidence of clinically significant renal dysfunction up to 52 weeks of randomized-controlled treatment.

Cardiovascular and Metabolic Effects of ANGPTL3 Antisense Oligonucleotides.

BACKGROUND: Epidemiologic and genomewide association studies have linked loss-of-function variants in ANGPTL3, encoding angiopoietin-like 3, with low levels of plasma lipoproteins. METHODS: We evaluated antisense oligonucleotides (ASOs) targeting Angptl3 messenger RNA (mRNA) for effects on plasma lipid levels, triglyceride clearance, liver triglyceride content, insulin sensitivity, and atherosclerosis in mice. Subsequently, 44 human participants (with triglyceride levels of either 90 to 150 mg per deciliter [1.0 to 1.7 mmol per liter] or >150 mg per deciliter, depending on the dose group) were randomly assigned to receive subcutaneous injections of placebo or an antisense oligonucleotide targeting ANGPTL3 mRNA in a single dose (20, 40, or 80 mg) or multiple doses (10, 20, 40, or 60 mg per week for 6 weeks). The main end points were safety, side-effect profile, pharmacokinetic and pharmacodynamic measures, and changes in levels of lipids and lipoproteins. RESULTS: The treated mice had dose-dependent reductions in levels of hepatic Angptl3 mRNA, Angptl3 protein, triglycerides, and low-density lipoprotein (LDL) cholesterol, as well as reductions in liver triglyceride content and atherosclerosis progression and increases in insulin sensitivity. After 6 weeks of treatment, persons in the multiple-dose groups had reductions in levels of ANGPTL3 protein (reductions of 46.6 to 84.5% from baseline, P<0.01 for all doses vs. placebo) and in levels of triglycerides (reductions of 33.2 to 63.1%), LDL cholesterol (1.3 to 32.9%), very-low-density lipoprotein cholesterol (27.9 to 60.0%), non-high-density lipoprotein cholesterol (10.0 to 36.6%), apolipoprotein B (3.4 to 25.7%), and apolipoprotein C-III (18.9 to 58.8%). Three participants who received the antisense oligonucleotide and three who received placebo reported dizziness or headache. There were no serious adverse events. CONCLUSIONS: Oligonucleotides targeting mouse Angptl3 retarded the progression of atherosclerosis and reduced levels of atherogenic lipoproteins in mice. Use of the same strategy to target human ANGPTL3 reduced levels of atherogenic lipoproteins in humans. (Funded by Ionis Pharmaceuticals; ClinicalTrials.gov number, NCT02709850 .).

The Effects of 2'-O-Methoxyethyl Containing Antisense Oligonucleotides on Platelets in Human Clinical Trials.

A thorough analysis of clinical trial data in the Ionis integrated safety database (ISDB) was performed to determine if there is a class effect on platelet numbers and function in subjects treated with 2'-O-methoxyethyl (2'MOE)-modified antisense oligonucleotides (ASOs). The Ionis ISDB includes over 2,600 human subjects treated with 16 different 2'MOE ASOs in placebo-controlled and open-label clinical trials over a range of doses up to 624 mg/week and treatment durations as long as 4.6 years. This analysis showed that there is no class generic effect on platelet numbers and no incidence of confirmed platelet levels below 50 K/µL in subjects treated with 2'MOE ASOs. Only 7 of 2,638 (0.3%) subjects treated with a 2'MOE ASO experienced a confirmed postbaseline (BSLN) platelet count between 100 and 50 K/µL. Three of sixteen 2'MOE ASOs had >10% incidence of platelet decreases >30% from BSLN, suggesting that certain sequences may associate with clinically insignificant platelet declines. Further to these results, we found no evidence that 2'MOE ASOs alter platelet function, as measured by the lack of clinically relevant bleeding in the presence or absence of other drugs that alter platelet function and/or number and by the results from trials conducted with the factor XI (FXI) ASO.