Fazirsiran for Adults With Alpha-1 Antitrypsin Deficiency Liver Disease: A Phase 2 Placebo Controlled Trial (SEQUOIA).

BACKGROUND & AIMS: Homozygous ZZ alpha-1 antitrypsin (AAT) deficiency produces mutant AAT (Z-AAT) proteins in hepatocytes, leading to progressive liver fibrosis. We evaluated the safety and efficacy of an investigational RNA interference therapeutic, fazirsiran, that degrades Z-AAT messenger RNA, reducing deleterious protein synthesis. METHODS: This ongoing, phase 2 study randomized 40 patients to subcutaneous placebo or fazirsiran 25, 100, or 200 mg. The primary endpoint was percent change in serum Z-AAT concentration from baseline to week 16. Patients with fibrosis on baseline liver biopsy received treatment on day 1, at week 4, and then every 12 weeks and had a second liver biopsy at or after weeks 48, 72, or 96. Patients without fibrosis received 2 doses on day 1 and at week 4. RESULTS: At week 16, least-squares mean percent declines in serum Z-AAT concentration were -61%, -83%, and -94% with fazirsiran 25, 100, and 200 mg, respectively, vs placebo (all P < .0001). Efficacy was sustained through week 52. At postdose liver biopsy, fazirsiran reduced median liver Z-AAT concentration by 93% compared with an increase of 26% with placebo. All fazirsiran-treated patients had histologic reduction from baseline in hepatic globule burden. Portal inflammation improved in 5 of 12 and 0 of 8 patients with a baseline score of >0 in the fazirsiran and placebo groups, respectively. Histologic meta-analysis of histologic data in viral hepatitis score improved by >1 point in 7 of 14 and 3 of 8 patients with fibrosis of >F0 at baseline in the fazirsiran and placebo groups, respectively. No adverse events led to discontinuation, and pulmonary function tests remained stable. CONCLUSIONS: Fazirsiran reduced serum and liver concentrations of Z-AAT in a dose-dependent manner and reduced hepatic globule burden. (ClinicalTrials.gov, Number NCT03945292).

Comparative optimization of polysaccharide-based nanoformulations for cardiac RNAi therapy.

Ionotropic gelation is widely used to fabricate targeting nanoparticles (NPs) with polysaccharides, leveraging their recognition by specific lectins. Despite the fabrication scheme simply involves self-assembly of differently charged components in a straightforward manner, the identification of a potent combinatory formulation is usually limited by structural diversity in compound collections and trivial screen process, imposing crucial challenges for efficient formulation design and optimization. Herein, we report a diversity-oriented combinatory formulation screen scheme to identify potent gene delivery cargo in the context of precision cardiac therapy. Distinct categories of cationic compounds are tested to construct RNA delivery system with an ionic polysaccharide framework, utilizing a high-throughput microfluidics workstation coupled with streamlined NPs characterization system in an automatic, step-wise manner. Sequential computational aided interpretation provides insights in formulation optimization in a broader scenario, highlighting the usefulness of compound library diversity. As a result, the out-of-bag NPs, termed as GluCARDIA NPs, are utilized for loading therapeutic RNA to ameliorate cardiac reperfusion damages and promote the long-term prognosis. Overall, this work presents a generalizable formulation design strategy for polysaccharides, offering design principles for combinatory formulation screen and insights for efficient formulation identification and optimization.

Optimized RNA interference therapeutics combined with interleukin-2 mRNA for treating hepatitis B virus infection.

This study aimed to develop a pan-genotypic and multifunctional small interfering RNA (siRNA) against hepatitis B virus (HBV) with an efficient delivery system for treating chronic hepatitis B (CHB), and explore combined RNA interference (RNAi) and immune modulatory modalities for better viral control. Twenty synthetic siRNAs targeting consensus motifs distributed across the whole HBV genome were designed and evaluated. The lipid nanoparticle (LNP) formulation was optimized by adopting HO-PEG2000-DMG lipid and modifying the molar ratio of traditional polyethylene glycol (PEG) lipid in LNP prescriptions. The efficacy and safety of this formulation in delivering siHBV (tLNP/siHBV) along with the mouse IL-2 (mIL-2) mRNA (tLNP/siHBVIL2) were evaluated in the rAAV-HBV1.3 mouse model. A siRNA combination (terms "siHBV") with a genotypic coverage of 98.55% was selected, chemically modified, and encapsulated within an optimized LNP (tLNP) of high efficacy and security to fabricate a therapeutic formulation for CHB. The results revealed that tLNP/siHBV significantly reduced the expression of viral antigens and DNA (up to 3log10 reduction; vs PBS) in dose- and time-dependent manners at single-dose or multi-dose frequencies, with satisfactory safety profiles. Further studies showed that tLNP/siHBVIL2 enables additive antigenic and immune control of the virus, via introducing potent HBsAg clearance through RNAi and triggering strong HBV-specific CD4+ and CD8+ T cell responses by expressed mIL-2 protein. By adopting tLNP as nucleic acid nanocarriers, the co-delivery of siHBV and mIL-2 mRNA enables synergistic antigenic and immune control of HBV, thus offering a promising translational therapeutic strategy for treating CHB.

Plozasiran, an RNA Interference Agent Targeting APOC3, for Mixed Hyperlipidemia.

BACKGROUND: Persons with mixed hyperlipidemia are at risk for atherosclerotic cardiovascular disease due to an elevated non-high-density lipoprotein (HDL) cholesterol level, which is driven by remnant cholesterol in triglyceride-rich lipoproteins. The metabolism and clearance of triglyceride-rich lipoproteins are down-regulated through apolipoprotein C3 (APOC3)-mediated inhibition of lipoprotein lipase. METHODS: We carried out a 48-week, phase 2b, double-blind, randomized, placebo-controlled trial evaluating the safety and efficacy of plozasiran, a hepatocyte-targeted APOC3 small interfering RNA, in patients with mixed hyperlipidemia (i.e., a triglyceride level of 150 to 499 mg per deciliter and either a low-density lipoprotein [LDL] cholesterol level of ≥70 mg per deciliter or a non-HDL cholesterol level of ≥100 mg per deciliter). The participants were assigned in a 3:1 ratio to receive plozasiran or placebo within each of four cohorts. In the first three cohorts, the participants received a subcutaneous injection of plozasiran (10 mg, 25 mg, or 50 mg) or placebo on day 1 and at week 12 (quarterly doses). In the fourth cohort, participants received 50 mg of plozasiran or placebo on day 1 and at week 24 (half-yearly dose). The data from the participants who received placebo were pooled. The primary end point was the percent change in fasting triglyceride level at week 24. RESULTS: A total of 353 participants underwent randomization. At week 24, significant reductions in the fasting triglyceride level were observed with plozasiran, with differences, as compared with placebo, in the least-squares mean percent change from baseline of -49.8 percentage points (95% confidence interval [CI], -59.0 to -40.6) with the 10-mg-quarterly dose, -56.0 percentage points (95% CI, -65.1 to -46.8) with the 25-mg-quarterly dose, -62.4 percentage points (95% CI, -71.5 to -53.2) with the 50-mg-quarterly dose, and -44.2 percentage points (95% CI, -53.4 to -35.0) with the 50-mg-half-yearly dose (P<0.001 for all comparisons). Worsening glycemic control was observed in 10% of the participants receiving placebo, 12% of those receiving the 10-mg-quarterly dose, 7% of those receiving the 25-mg-quarterly dose, 20% of those receiving the 50-mg-quarterly dose, and 21% of those receiving the 50-mg-half-yearly dose. CONCLUSIONS: In this randomized, controlled trial involving participants with mixed hyperlipidemia, plozasiran, as compared with placebo, significantly reduced triglyceride levels at 24 weeks. A clinical outcomes trial is warranted. (Funded by Arrowhead Pharmaceuticals; MUIR ClinicalTrials.gov number NCT04998201.).

Zodasiran, an RNAi Therapeutic Targeting ANGPTL3, for Mixed Hyperlipidemia.

BACKGROUND: Angiopoietin-like 3 (ANGPTL3) inhibits lipoprotein and endothelial lipases and hepatic uptake of triglyceride-rich lipoprotein remnants. ANGPTL3 loss-of-function carriers have lower levels of triglycerides, low-density lipoprotein (LDL) cholesterol, high-density lipoprotein (HDL) cholesterol, and non-HDL cholesterol and a lower risk of atherosclerotic cardiovascular disease than noncarriers. Zodasiran is an RNA interference (RNAi) therapy targeting expression of ANGPTL3 in the liver. METHODS: We conducted a double-blind, placebo-controlled, dose-ranging phase 2b trial to evaluate the safety and efficacy of zodasiran in adults with mixed hyperlipidemia (fasting triglyceride level of 150 to 499 mg per deciliter and either an LDL cholesterol level of ≥70 mg per deciliter or a non-HDL cholesterol level of ≥100 mg per deciliter). Eligible patients were randomly assigned in a 3:1 ratio to receive subcutaneous injections of zodasiran (50, 100, or 200 mg) or placebo on day 1 and week 12 and were followed through week 36. The primary end point was the percent change in the triglyceride level from baseline to week 24. RESULTS: A total of 204 patients underwent randomization. At week 24, substantial mean dose-dependent decreases from baseline in ANGPTL3 levels were observed with zodasiran (difference in change vs. placebo, -54 percentage points with 50 mg, -70 percentage points with 100 mg, and -74 percentage points with 200 mg), and significant dose-dependent decreases in triglyceride levels were observed (difference in change vs. placebo, -51 percentage points, -57 percentage points, and -63 percentage points, respectively) (P<0.001 for all comparisons). Other differences in change from baseline as compared with placebo included the following: for non-HDL cholesterol level, -29 percentage points with 50 mg, -29 percentage points with 100 mg, and -36 percentage points with 200 mg; for apolipoprotein B level, -19 percentage points, -15 percentage points, and -22 percentage points, respectively; and for LDL cholesterol level, -16 percentage points, -14 percentage points, and -20 percentage points, respectively. We observed a transient elevation in glycated hemoglobin levels in patients with preexisting diabetes who received the highest dose of zodasiran. CONCLUSIONS: In patients with mixed hyperlipidemia, zodasiran was associated with significant decreases in triglyceride levels at 24 weeks. (Funded by Arrowhead Pharmaceuticals; ARCHES-2 ClinicalTrials.gov number, NCT04832971.).

The Growing Class of Novel RNAi Therapeutics.

The clinical use of RNA interference (RNAi) molecular mechanisms has introduced a novel, growing class of RNA therapeutics capable of treating diseases by controlling target gene expression at the posttranscriptional level. With the newly approved nedosiran (Rivfloza), there are now six RNAi-based therapeutics approved by the United States Food and Drug Administration (FDA). Interestingly, five of the six FDA-approved small interfering RNA (siRNA) therapeutics [patisiran (Onpattro), lumasiran (Oxlumo), inclisiran (Leqvio), vutrisiran (Amvuttra), and nedosiran] were revealed to act on the 3'-untranslated regions of target mRNAs, instead of coding sequences, thereby following the common mechanistic action of genome-derived microRNAs (miRNA). Furthermore, three of the FDA-approved siRNA therapeutics [patisiran, givosiran (Givlaari), and nedosiran] induce target mRNA degradation or cleavage via near-complete rather than complete base-pair complementarity. These features along with previous findings confound the currently held characteristics to distinguish siRNAs and miRNAs or biosimilars, of which all converge in the RNAi regulatory pathway action. Herein, we discuss the RNAi mechanism of action and current criteria for distinguishing between miRNAs and siRNAs while summarizing the common and unique chemistry and molecular pharmacology of the six FDA-approved siRNA therapeutics. The term "RNAi" therapeutics, as used previously, provides a coherently unified nomenclature for broader RNAi forms as well as the growing number of therapeutic siRNAs and miRNAs or biosimilars that best aligns with current pharmacological nomenclature by mechanism of action. SIGNIFICANCE STATEMENT: The common and unique chemistry and molecular pharmacology of six FDA-approved siRNA therapeutics are summarized, in which nedosiran is newly approved. We point out rather a surprisingly mechanistic action as miRNAs for five siRNA therapeutics and discuss the differences and similarities between siRNAs and miRNAs that supports using a general and unified term "RNAi" therapeutics to align with current drug nomenclature criteria in pharmacology based on mechanism of action and embraces broader forms and growing number of novel RNAi therapeutics.

Patisiran, an RNAi therapeutic for hereditary transthyretin-mediated amyloidosis: Sub-analysis in Taiwanese patients from the APOLLO study.

BACKGROUND: To examine the efficacy and safety of patisiran, an RNA interference therapeutic, in patients from Taiwan with hereditary transthyretin-mediated (hATTR) amyloidosis with polyneuropathy. METHODS: The APOLLO phase 3 trial included patients from Taiwan who received patisiran 0.3 mg/kg intravenously or placebo once every 3 weeks (q3w) for 18 months (18 M), followed by patisiran 0.3 mg/kg q3w in an ongoing global open-label extension (OLE) study. The primary endpoint was change from baseline in modified Neuropathy Impairment Score +7 (mNIS+7) at 18 M. RESULTS: Eighteen Taiwanese patients were enrolled in APOLLO (patisiran, n = 8; placebo, n = 10; all A97S gene variant) and 14 continued in the global OLE. In this Taiwanese sub-population, beneficial treatment effects at 18 M were observed in mNIS+7 (least squares mean difference in change from baseline [patisiran-placebo], -26.5 points; 95% confidence interval: -45.5, -7.5). Patients who switched from placebo to patisiran demonstrated slowing of polyneuropathy progression at month 12 in the global OLE, while those who received patisiran in APOLLO maintained the beneficial treatment effects. Patisiran had an acceptable safety profile in the Taiwanese sub-population. CONCLUSION: This analysis suggests that patisiran is well tolerated and may provide a substantial clinical benefit for Taiwanese patients with hATTR amyloidosis with polyneuropathy. TRIAL REGISTRATION INFORMATION: The studies were registered on the ClinicalTrials.gov. The APOLLO study ClinicalTrials.gov identifier is NCT01960348 (https://clinicaltrials.gov/ct2/show/NCT01960348), with the registration date of October 10, 2013, and the first patient was enrolled on December 13, 2013. For the global OLE, the ClinicalTrials.gov identifier is NCT02510261 (https://clinicaltrials.gov/ct2/show/NCT02510261) with the registration date of July 29, 2015, and the first patient was enrolled on July 13, 2015. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that treatment with patisiran is safe and efficacious in Taiwanese patients with hereditary transthyretin-mediated amyloidosis with polyneuropathy.

Recent updates on therapeutic targeting of lipoprotein(a) with RNA interference.

PURPOSE OF REVIEW: RNA interference (RNAi)-based therapies that target specific gene products have impacted clinical medicine with 16 FDA approved drugs. RNAi therapy focused on reducing plasma lipoprotein(a) [Lp(a)] levels are under evaluation. RECENT FINDINGS: RNAi-based therapies have made significant progress over the past 2 decades and currently consist of antisense oligonucleotides (ASO) and small interfering RNA (siRNA). Chemical modification of the RNA backbone and conjugation of siRNA enables efficient gene silencing in hepatocytes allowing development of effective cholesterol lowering therapies. Multiple lines of evidence suggest a causative role for Lp(a) in atherosclerotic cardiovascular disease, and recent analyses indicate that Lp(a) is more atherogenic than low density lipoprotein- cholesterol (LDL-C). These findings have led to the 'Lp(a) hypothesis' that lowering Lp(a) may significantly improve cardiovascular outcomes. Four RNAi-based drugs have completed early phase clinical trials demonstrating >80% reduction in plasma Lp(a) levels. Phase 3 clinical trials examining clinical outcomes with these agents are currently underway. SUMMARY: Currently, four RNAi-based drugs have been shown to be effective in significantly lowering plasma Lp(a) levels. Clinical outcome data from phase 3 trials will evaluate the Lp(a) hypothesis.

SiRNA-HIF-1α delivered by attenuated Salmonella enhances the efficacy of Lenvatinib against hepatocellular carcinoma.

The treatment of hepatocellular carcinoma (HCC) remains a major challenge in the medical field. Lenvatinib, a multi-target tyrosine kinase inhibitor, has demonstrated anti-HCC effects by targeting and inhibiting pathways such as vascular endothelial growth factor receptor 1-3 (VEGFR1-3). However, the therapeutic efficacy of Lenvatinib is subject to various influences, with the hypoxic microenvironment of the tumor being a pivotal factor. Consequently, altering the hypoxic milieu of the tumor emerges as a viable strategy to augment the efficacy of Lenvatinib. Hypoxia-inducible factor-1α (HIF-1α), synthesized by tumor cells in response to oxygen-deprived conditions, regulates the expression of resistance genes, promotes tumor angiogenesis and cell proliferation, enhances tumor cell invasion, and confers resistance to radiotherapy and chemotherapy. Thus, we constructed a self-designed siRNA targeting HIF-1α to suppress its expression and improve the efficacy of Lenvatinib in treating HCC. The therapeutic efficacy of siRNA-HIF-1α in combination with Lenvatinib on HCC were evaluated through in vivo and in vitro experiments. The results showed that the recombinant Salmonella delivering siRNA-HIF-1α in combination with Lenvatinib effectively inhibited tumor growth and prolonged the survival of tumor-bearing mice. This treatment approach reduced cell proliferation and angiogenesis in HCC tissues while promoting tumor cell apoptosis. Additionally, this combined therapy significantly increased the infiltration of T lymphocytes and M1 macrophages within the tumor microenvironment, as well as elevated the proportion of immune cells in the spleen, thereby potentiating the host's immune response against the tumor.

Nephrocalcinosis can disappear in infants receiving early lumasiran therapy.

BACKGROUND: Lumasiran is the first RNA interference (RNAi) therapy of primary hyperoxaluria type 1 (PH1). Here, we report on the rapid improvement and even disappearance of nephrocalcinosis after early lumasiran therapy. CASE-DIAGNOSIS/TREATMENT: In patient 1, PH1 was suspected due to incidental discovery of nephrocalcinosis stage 3 in a 4-month-old boy. Bilateral nephrocalcinosis stage 3 was diagnosed in patient 2 at 22 months concomitantly to acute pyelonephritis. Urinary oxalate (UOx) and glycolate (UGly) were increased in both patients allowing to start lumasiran therapy before genetic confirmation. Nephrocalcinosis started to improve and disappeared after 27 months and 1 year of treatment in patients 1 and 2, respectively. CONCLUSION: These cases illustrate the efficacy of early lumasiran therapy in infants to improve and even normalize nephrocalcinosis. As proposed in the 2023 European guidelines, the interest of starting treatment quickly without waiting for genetic confirmation may have an impact on long-term outcomes.

Advances in RNAi therapies for gastric cancer: Targeting drug resistance and nanoscale delivery.

Gastric cancer poses a significant health challenge, and exploring innovative therapeutic strategies is imperative. RNA interference (RNAi) has employed as an important therapeutic strategy for diseases by selectively targeting key pathways involved in diseases pathogenesis. Small interfering RNA (siRNA), a potent RNAi tool, possesses the capability to silence genes and downregulate their expression. This review provides a comprehensive examination of the potential applications of small interfering RNA (siRNA) and short hairpin RNA (shRNA), supplemented by an in-depth analysis of nanoscale delivery systems, in the context of gastric cancer treatment. The potential of siRNA to markedly diminish the proliferation and invasion of gastric cancer cells through the modulation of critical molecular pathways, including PI3K, Akt, and EMT, is highlighted. Besides, siRNA demonstrates its efficacy in inducing chemosensitivity in gastric tumor cells, thus impeding tumor progression. However, the translational potential of unmodified siRNA faces challenges, particularly in vivo and during clinical trials. To address this, we underscore the pivotal role of nanostructures in facilitating the delivery of siRNA to gastric cancer cells, effectively suppressing their progression and enhancing gene silencing efficiency. These siRNA-loaded nanoparticles exhibit robust internalization into gastric cancer cells, showcasing their potential to significantly reduce tumor progression. The translation of these findings into clinical trials holds promise for advancing the treatment of gastric cancer patients.

RNAi-Based Therapy: Combating Shrimp Viral Diseases.

Shrimp aquaculture has become a vital industry, meeting the growing global demand for seafood. Shrimp viral diseases have posed significant challenges to the aquaculture industry, causing major economic losses worldwide. Conventional treatment methods have proven to be ineffective in controlling these diseases. However, recent advances in RNA interference (RNAi) technology have opened new possibilities for combating shrimp viral diseases. This cutting-edge technology uses cellular machinery to silence specific viral genes, preventing viral replication and spread. Numerous studies have shown the effectiveness of RNAi-based therapies in various model organisms, paving the way for their use in shrimp health. By precisely targeting viral pathogens, RNAi has the potential to provide a sustainable and environmentally friendly solution to combat viral diseases in shrimp aquaculture. This review paper provides an overview of RNAi-based therapy and its potential as a game-changer for shrimp viral diseases. We discuss the principles of RNAi, its application in combating viral infections, and the current progress made in RNAi-based therapy for shrimp viral diseases. We also address the challenges and prospects of this innovative approach.

RNAi therapies: Expanding applications for extrahepatic diseases and overcoming delivery challenges.

The era of RNA medicine has become a reality with the success of messenger RNA (mRNA) vaccines against COVID-19 and the approval of several RNA interference (RNAi) agents in recent years. Particularly, therapeutics based on RNAi offer the promise of targeting intractable and previously undruggable disease genes. Recent advances have focused in developing delivery systems to enhance the poor cellular uptake and insufficient pharmacokinetic properties of RNAi therapeutics and thereby improve its efficacy and safety. However, such approach has been mainly achieved via lipid nanoparticles (LNPs) or chemical conjugation with N-Acetylgalactosamine (GalNAc), thus current RNAi therapy has been limited to liver diseases, most likely to encounter liver-targeting limitations. Hence, there is a huge unmet medical need for intense evolution of RNAi therapeutics delivery systems to target extrahepatic tissues and ultimately extend their indications for treating various intractable diseases. In this review, challenges of delivering RNAi therapeutics to tumors and major organs are discussed, as well as their transition to clinical trials. This review also highlights innovative and promising preclinical RNAi-based delivery platforms for the treatment of extrahepatic diseases.

Direct cytoplasmic delivery of RNAi therapeutics through a non-lysosomal pathway for enhanced gene therapy.

The first approved RNAi therapeutics, ONPATTRO, in 2017 moves the concept of RNA interference (RNAi) therapy from research to clinical reality, raising the hopes for the treatment of currently incurable diseases. However, RNAi therapeutics are still facing two main challenges-susceptibility to enzymatic degradation and low ability to escape from endo/lysosome into the cytoplasm. Therefore, we developed disulfide-based nanospheres (DBNPs) as universal vehicles to achieve efficient RNA delivery to address these problems. Notably, the DBNPs possess unique and desirable features, including improved resistance to nuclease degradation, direct cytoplasmic delivery through thiol-mediated cellular uptake, and cytosolic environment-responsive release, greatly enhancing the bioavailability of RNA therapeutics. Additionally, DBNPs are superior in terms of overcoming formidable physiological barriers, including vascular barriers and impermeable tumor tissues. Owning to these advantages, the DBNPs exhibit efficient gene silencing effect when delivering either small interfering RNA (siRNA) or microRNA in various cell lines and generate remarkable growth inhibition in the zebrafish and mouse model of pancreatic tumors as compared to traditional delivery vectors, such as PEI. Therefore, DBNPs have potential application prospect in RNAi therapy both in vitro and in vivo. STATEMENT OF SIGNIFICANCE: RNA interference (RNAi) therapeutics could target and alter any disease-related mRNA translation, thus have great potential in clinical application. Delivery efficiency of RNA modalities into cell cytoplasm is the main problem that currently limit RNAi therapeutics to release their full potential. Most of the known delivery materials suffer from the endo/lysosomal entrapment and enzymatic degradation during endocytosis-dependent uptake, resulting unsatisfied efficiency of the cytoplasmic release. Here, we developed disulfide-based nanospheres could directly transfer RNA modalities into the cytoplasm and significantly enhance the delivery efficiency, thus holding great potential in RNAi therapy.

RNAi therapeutics for diseases involving protein aggregation: fazirsiran for alpha-1 antitrypsin deficiency-associated liver disease.

INTRODUCTION: Therapeutic agents that prevent protein misfolding or promote protein clearance are being studied to treat proteotoxic diseases. Among them, alpha-1 antitrypsin deficiency (AATD) is caused by mutations in the alpha-1 antitrypsin (SERPINA1) gene. Fazirsiran is a small interfering RNA (siRNA) that is intended to address the underlying cause of liver disease associated with AATD through the RNA interference (RNAi) mechanism. AREAS COVERED: This article describes the role of misfolded proteins and protein aggregates in disease and options for therapeutic approaches. The RNAi mechanism is discussed, along with how the siRNA therapeutic fazirsiran for the treatment of AATD was developed. We also describe the implications of siRNA therapeutics in extrahepatic diseases. EXPERT OPINION: Using RNAi as a therapeutic approach is well suited to treat disease in conditions where an excess of a protein or the effect of an abnormal mutated protein causes disease. The results observed for the first few siRNA therapeutics that were approved or are in development provide an important promise for the development of future drugs that can address such conditions in a specific and targeted way. Current developments should enable the use of RNAi therapeutics outside the liver, where there are many more possible diseases to address.

When certain proteins in the body are not produced correctly, it can result in disease. Examples of such diseases include alpha-1 antitrypsin deficiency (AATD), hereditary transthyretin amyloidosis (ATTR), amyotrophic lateral sclerosis (ALS), Alzheimer's disease, and Parkinson's disease, where misfolded proteins can form harmful aggregates. Research is underway to develop new therapies such as small interfering RNA (siRNA), antisense oligonucleotides, monoclonal antibodies, clustered regularly interspaced short palindromic repeats (CRISPR), and small molecule protein modulators to prevent protein aggregates. An example of an experimental siRNA therapy for patients with AATD is fazirsiran, designed to prevent the production of mutated alpha-1 antitrypsin (Z-AAT) and allows the liver to clear previously accumulated Z-AAT protein, which is believed to be responsible for causing AATD liver disease. This review summarizes the development of fazirsiran and describes how it helps our understanding and treatment of diseases associated with protein aggregation.

Autophagy-Interfering Nanoboat Drifting along CD44-Golgi-ER Flow as RNAi Therapeutics for Hepatic Fibrosis.

The upregulated autophagy fuels the activation of hepatic stellate cells (HSCs) to promote hepatic fibrosis. However, the lack of specific inhibitors targeting autophagy and high requirements for cell targeting impede the application of antifibrotic therapy that targets autophagy. RNA interference (RNAi)-based short interfering RNA (siRNA) provides an approach to specifically inhibit autophagy. The therapeutic potential of siRNA, however, is far from being exploited due to the lack of safe and effective delivery vehicles. The cytoplasmic delivery of siRNA is essential for RNAi, and the intracellular trafficking pathway of vehicles determines the fate of siRNA. Unfortunately, the lysosomal degradation pathway, the intracellular fate of most gene vehicles, impedes RNAi efficiency. Inspired by the trafficking pathway of some viruses infecting cells, KDEL-grafted chondroitin sulfate (CK) was designed to alter the intracellular delivery fate of siRNA. The well-designed CD44-Golgi-ER trafficking pathway of CK was realized by triple cascade targeting including (1) CD44 targeting mediated by chondroitin sulfate, (2) Golgi apparatus targeting mediated by the caveolin-mediated endocytic pathway, and (3) endoplasmic reticulum (ER) targeting mediated by coat protein I (COP I) vesicles. CK was adsorbed on the complex of cationic liposomes (Lip) encapsulating siRNA targeting autophagy-related gene 7 (siATG7) to afford Lip/siATG7/CK. Lip/siATG7/CK functions as a drifting boat that follows the CD44-Golgi-ER flow and travels downstream to its destination (ER), bypassing the lysosomal degradation pathway and endowing HSCs with excellent RNAi efficiency. The efficient downregulation of ATG7 leads to an excellent antifibrotic effect both in vitro and in vivo.

Evaluation of RNAi therapeutics VIR-2218 and ALN-HBV for chronic hepatitis B: Results from randomized clinical trials.

BACKGROUND & AIMS: Current therapy for chronic hepatitis B virus (cHBV) infection involves lifelong treatment. New treatments that enable HBV functional cure would represent a clinically meaningful advance. ALN-HBV and VIR-2218 are investigational RNA interference therapeutics that target all major HBV transcripts. METHODS: We report on: i) the safety of single doses of VIR-2218 (modified from ALN-HBV by enhanced stabilization chemistry plus technology to reduce off-target, seed-mediated binding while maintaining on-target antiviral activity) and ALN-HBV in humanized mice; ii) a cross-study comparison of the safety of single doses of VIR-2218 and ALN-HBV in healthy human volunteers (n = 24 and n = 49, respectively); and iii) the antiviral activity of two doses of 20, 50, 100, 200 mg of VIR-2218 (total n = 24) vs. placebo (n = 8), given 4 weeks apart, in participants with cHBV infection. RESULTS: In humanized mice, alanine aminotransferase (ALT) levels were markedly lower following administration of VIR-2218 compared with ALN-HBV. In healthy volunteers, post-treatment ALT elevations occurred in 28% of participants receiving ALN-HBV compared with none in those receiving VIR-2218. In participants with cHBV infection, VIR-2218 was associated with dose-dependent reductions in hepatitis B surface antigen (HBsAg). The greatest mean reduction of HBsAg at Week 20 in participants receiving 200 mg was 1.65 log IU/ml. The HBsAg reduction was maintained at 0.87 log IU/ml at Week 48. No participants had serum HBsAg loss or hepatitis B surface antibody seroconversion. CONCLUSIONS: VIR-2218 demonstrated an encouraging hepatic safety profile in preclinical and clinical studies as well as dose-dependent HBsAg reductions in patients with cHBV infection. These data support future studies with VIR-2218 as part of combination regimens with a goal of HBV functional cure. TRIAL REGISTRATION: ClinicalTrials.gov identifiers: NCT02826018 and NCT03672188. IMPACT AND IMPLICATIONS: A significant unmet need exists for therapies for chronic HBV (cHBV) infection that achieve functional cure. We report clinical and non-clinical data on two investigational small-interfering RNAs that target HBx, ALN-HBV and VIR-2218, demonstrating that incorporation of enhanced stabilization chemistry plus technology in VIR-2218 reduces its propensity to cause ALT elevations relative to its parent compound, ALN-HBV. We also show that VIR-2218 reduces hepatitis B surface antigen levels in a dose-dependent manner in participants with cHBV infection. These studies support the continued development of VIR-2218 as part of therapeutic regimens for cHBV infection, with the goal of a functional cure, and are important for HBV researchers and physicians.

Bioengineered Bacteriophage-Like Nanoparticles as RNAi Therapeutics to Enhance Radiotherapy against Glioblastomas.

Since glioblastomas (GBMs) are radioresistant malignancies and most GBM recurrences occur in radiotherapy, increasing the effectiveness of radiotherapy by gene-silencing has recently attracted attention. However, the difficulty in precisely tuning the composition and RNA loading in nanoparticles leads to batch-to-batch variations of the RNA therapeutics, thus significantly restricting their clinical translation. Here, we bioengineer bacteriophage Qß particles with a designed broccoli light-up three-way junction (b-3WJ) RNA scaffold (contains two siRNA/miRNA sequences and one light-up aptamer) packaging for the silencing of genes in radioresistant GBM cells. The in vitro results demonstrate that the cleavage of de novo designed b-3WJ RNA by Dicer enzyme can be easily monitored in real-time using fluorescence microscopy, and the TrQß@b-3WJLet-7gsiEGFR successfully knocks down EGFR and IKKα simultaneously and thereby inactivates NF-κB signaling to inhibit DNA repair. Delivery of TrQß@b-3WJLet-7gsiEGFR through convection-enhanced delivery (CED) infusion followed by 2Gy X-ray irradiation demonstrated that the median survival was prolonged to over 60 days compared with the 2Gy X-ray irradiated group (median survival: 31 days). Altogether, the results of this study could be critical for the design of RNAi-based genetic therapeutics, and CED infusion serves as a powerful delivery system for promoting radiotherapy against GBMs without evidence of systemic toxicity.

Cation-free siRNA-cored nanocapsules for tumor-targeted RNAi therapy.

Cation-associated cytotoxicity limits the systemic administration of RNA delivery in vivo, demanding the development of non-cationic nanosystems. In this study, cation-free polymer-siRNA nanocapsules with disulfide-crosslinked interlayer, namely T-SS(-), were prepared via the following steps: 1) complexation of siRNA with a cationic block polymer cRGD-poly(ethylene glycol)-b-poly[(2-aminoethanethiol)aspartamide]-b-poly{N'-[N-(2-aminoethyl)-2-ethylimino-1-aminomethyl]aspartamide}, abbreviated as cRGD-PEG-PAsp(MEA)-PAsp(C=N-DETA), 2) interlayer crosslinking via disulfide bond in pH 7.4 solution, and 3) removal of cationic DETA pendant at pH 5.0 via breakage of imide bond. The cationic-free nanocapsules with siRNA cores not only showed great performance (such as efficient siRNA encapsulation, high stability in serum, cancer cell targeting via cRGD modification, and GSH-triggered siRNA release), but also achieved tumor-targeted gene silencing in vivo. Moreover, the nanocapsules loaded with siRNA against polo-like kinase 1 (siRNA-PLK1) significantly inhibited tumor growth without showing cation-associated toxicity side effects and remarkably improved the survival rate of PC-3 tumor-bearing mice. The cation-free nanocapsules could potentially serve as a safe and effective platform for siRNA delivery. STATEMENT OF SIGNIFICANCE: Cation-associated toxicity limits the clinical translation of cationic carriers for siRNA delivery. Recently, several non-cationic carriers, such as siRNA micelles, DNA-based nanogels, and bottlebrush-architectured poly(ethylene glycol), have been developed to deliver siRNA. However, in these designs, siRNA as a hydrophilic macromolecule was attached to the nanoparticle surface instead of being encapsulated. Thus, it was easily degraded by serum nuclease and often induced immunogenicity. Herein, we demonstrate a new type of cation-free siRNA-cored polymeric nanocapsules. The developed nanocapsules not only showed capacities including efficient siRNA encapsulation, high stability in serum, and cancer cell targeting via cRGD modification, but also achieved an efficient tumor-targeted gene silencing in vivo. Importantly, unlike cationic carriers, the nanocapsules exhibited no cation-associated side effects.