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miRNA (microRNA) drugs: Status Trends Technology.
miRNA, also known as microRNA, is a ribonucleic acid (RNA) molecule with a length of about 21 to 23 nucleotides widely found in eukaryotes, which can regulate the expression of other genes.
miRNA comes from RNA (non-coding RNA) that is transcribed from DNA but cannot be further translated into protein.
miRNA binds to target messenger ribonucleic acid (mRNA) to inhibit post-transcriptional gene expression [3], and plays an important role in regulating gene expression, cell cycle, and biological development timing. In animals, a single microRNA can usually regulate dozens of genes.
1. Overview of miRNA drugs-leading the revolution in biomedicine
1.1 Significant advantages of miRNA drugs
When it comes to nucleic acid drugs, which can be called the third revolution of biomedicine, the central principle has to be mentioned.
The central law refers to the process of transcription and translation in which genetic information is transferred from DNA to RNA, and from RNA to protein, and the replication process in which genetic information is transferred from DNA to DNA.
This is the law followed by all organisms with cellular structures.
Nucleic acid drugs are drugs that are different from traditional drugs and act directly on DNA or RNA.
This report focuses on the analysis of miRNA drugs with fewer bases (often less than 30nt) in nucleic acid drugs.
Nucleic acid drugs based on RNA and DNA have advantages over traditional drugs. At present, small molecules and proteins are the two main types of drugs in the mainstream of biopharmaceuticals.
Small molecule drugs inhibit target proteins through competitive binding, while protein-based drugs (such as antibodies) can bind to multiple targets with high specificity.
Compared with antibody drugs, small nucleic acid drugs have a richer choice of targets, especially for some genes that are difficult for protein drugs to be formulated, and some short-sequence nucleic acid drugs can usually be chemically synthesized, and preparation is relatively simple and easier Ensure synthetic availability and batch-to-batch stability.
As a representative of nucleic acid drugs, miRNA drugs have shown great potential, including antisense oligonucleotides (ASO), small hairpin RNA (shRNA), and small interfering RNA (siRNA).
miRNA drugs start treatment at the gene level and have obvious advantages over protein drugs.
In the discovery process of traditional small molecule compounds, the discovery of lead compounds has a relatively large chance, and the biggest advantage of miRNA drugs is that they only need to develop suitable sequences for the genes of miRNA drugs to develop new drugs.
This approach avoids The blindness in the development process is eliminated.
After determining the target sequence of miRNA drugs, the process is faster and time-consuming is significantly shorter, and the biological specificity of small nucleic acid drugs is also very high.
Over the years, the chemical modification of miRNAs and improvements in delivery systems have not only enhanced specificity and efficacy, but also reduced side effects.
In recent years, miRNA drugs have become a promising tool for the treatment of various diseases due to their unique advantages.
1.2 The development status of miRNA drugs
At present, miRNA drugs are mainly divided into antisense oligonucleotide drugs (ASO) and RNA interference drugs (siRNA, miRNA).
Since there are no approved drugs for miRNA, this report will focus on the analysis of two types of miRNA drugs, ASO and siRNA.
Judging from the approval situation, since the first miRNA drug Vitravene was launched, the small nucleic acid industry has experienced 20 years.
So far, a total of 10 RNA drugs have been launched. Moreover, due to the gradual maturity of industry technology and supervision, In recent years, the approval of miRNA drugs has been significantly accelerated.
Before 2015, there were only 2 drugs on the market in the miRNA field. Since 2018, 6 drugs have been on the market.
At present, from the perspective of therapeutic areas, the key therapeutic areas of miRNA drug research and development include Duchenne muscular dystrophy, tumors, cystic fibrosis and other diseases.
Because miRNA drugs have the dual characteristics of genetic modification and traditional drugs, they will show their talents in many fields in the future, and are expected to perform well in the fields of genetic diseases and viral infectious diseases.
At present, many miRNA drugs have been approved and have achieved certain commercial success.
The successful representative drug is the ASO drug Nusinersen, which is used to treat spinal muscular atrophy (SMA).
As of the end of 2019, its cumulative sales were 4.7 billion US dollars. In addition, the two currently approved siRNA drugs Patisiran and Givosiran have also achieved Excellent sales, Patisiran’s first year of sales in 2019 has exceeded 150 million US dollars.
2. The mechanism and development trend of miRNA drugs
2.1 The mechanism of action of ASO and siRNA drugs (omitted)
2.2 Current status of pipeline R&D of ASO and siRNA
For ASO drugs, the current global R&D of ASO drugs is still in the development stage of the industry.
Due to the high barriers to entry in the industry, there are fewer than 300 projects after the global laboratory stage, and its therapeutic areas are mainly focused on tumors, nerves and muscle diseases.
In terms of industry concentration, the leading companies such as Ionis, Sarepta, and WAVElife have a long-term accumulation, and the industry concentration is relatively high.
This is mainly because ASO drugs are relatively small in size, low in hydrophilicity, and have a certain ability to directly enter cells through pinocytosis.
In the early stages of the industry, most of the direct chemical modification of ASO was used (reducing delivery efficiency in exchange for simpler druggability) It is easier for companies that entered the industry early to form patents.
However, in recent years, with the emergence of new delivery systems and the delivery efficiency of purely chemically modified ASOs are still unsatisfactory, a group of biomedical companies that take delivery technology as an entry point are entering the ASO field.
For siRNA drugs, similar to ASO, the current global R&D of siRNA drugs is still in the industry development stage.
There are about 300 projects after the global laboratory stage.
The overall development trend is good. Its therapeutic areas are mainly concentrated in tumor, neurology and ophthalmology.
In terms of industry concentration, leading companies such as Alnylam, Dicerna, Arrowhead and other companies have accumulated for a long time, and the industry concentration is relatively high.
Since siRNA has a larger molecular weight and stronger charge than ASO, it is more difficult for siRNA to enter cells by itself.
Therefore, siRNA drugs have higher requirements for carriers. This is why siRNA drugs are approved later than ASO drugs. The big reason.
Currently, the leading companies in the siRNA field have introduced their own or authorized delivery platforms based on their own technical characteristics.
Delivery technology is a major entry point for biomedical companies to enter the siRNA field.
2.3 Development trend of chemical modification of miRNA drugs
Naturally occurring miRNAs have poor stability and very low specificity, and have many side effects in the body.
Chemical modification is one of the effective methods to enhance the delivery of small nucleotide drugs. Modifications of the phosphate backbone, ribose moiety, and base itself have been widely adopted to improve the drug-like properties of oligonucleotide drugs, thereby enhancing delivery.
Specifically, modifications are used to improve the pharmacokinetics, pharmacodynamics, and biodistribution of oligonucleotides.
For the functionality of certain treatments, specific modifications are required.
For example, the combination of 2′-OMe and phosphorothioate (PS) modifications facilitates the systemic administration of cholesterol-bound siRNA and achieves effective gene silencing in vivo, such as 2′-OMe and 2′-F The combination has been used in ONPATTRO; phosphorothioate (PS), 2′-OMe, 2′-F and 2′-deoxy modified inclisiran (ALN-PCSsc) has also been used to treat hypercholesterolemia.
At present, Alnylam, Arrowhead, Silence, Dicerna and other leading companies have adopted a variety of chemical modification methods in their own ASO and siRNA pipeline druggability design to increase the druggability of their drugs, and with regard to nucleic acid sequences and chemical modifications
With the deepening of cognition, the chemical modification of nucleic acids has also gone through from the earliest non-modification to partial modification to the current full modification.
At present, after decades of development for the chemical modification of nucleic acids, three generations of technology have been developed.
The most commonly used chemical modifications are the first-generation phosphorothioate and the second-generation methylphosphonate.
Methyl phosphonate is uncharged, so it is more lipophilic than natural DNA or RNA and can penetrate cells better.
However, the solubility of methyl phosphonate has always been a problem. It is often bound to the membrane, and miRNAs can enter the cytoplasm with only minor modifications.
Therefore, the third-generation PNA, LNA and other technologies were subsequently produced. However, these technologies still have more or less potential liver toxicity and low efficiency.
The industry and academia are also aware that chemical modification is very important for miRNA drug delivery, but many problems such as targeting are difficult to rely solely on chemical modification.
In the end, it still needs to rely on the delivery system.
2.4 Overview of the development of miRNA drug delivery systems
For miRNA drugs to be effective, they need to overcome a series of challenges such as nuclease degradation, short half-life, immune recognition in the blood circulation, accumulation in target tissues, transmembrane transport, and escape from endosomes and lysosomes.
Although the combination of chemical modification can greatly reduce the stability of nucleases and avoid immune recognition, other problems still need to be solved, and the drug-carrying system can greatly solve the problems that cannot be solved by chemical modification, and improve miRNA drug treatment.
Effectiveness and safety, so the carrier system can be said to be the top priority of miRNA administration.
At present, for RNAi drug delivery, a good delivery system is the top priority to solve the challenge.
Currently, one of the drugs approved by the leading company Alnylam uses liposomal LNP and the other uses Galnac delivery system.
3. Antisense Oligonucleotide (ASO) has been on the market and analysis of potential drugs (omitted)
There are currently 8 ASO drugs on the global market, and the mechanisms of action of these 8 drugs are not exactly the same.
- 3.1 Fomivirsen-pioneering ASO drugs
- 3.2 Mipomersen—the first ASO drug in the field of lipid-lowering
- 3.3 Eteplisen—ASO drug moving forward in controversy
- 3.4 Nusinersen-the first blockbuster
- 3.5 Inotersen—commercialization has fallen short
- 3.6 Volanesoren—waiting to continue to blossom and bear fruit
- 3.7 Golodirsen and Viltolarsen-follow-up worthy of attention
- 3.8 The key factors for ASO success
Overall, the commercialization of ASO drugs is mainly based on two aspects:
1. Research on the pathogenesis of the disease;
2. Clinical efficacy of itself.
In the study of disease pathology, whether it is the emergence of DMD exon 51 or 53 drugs, or the emergence of SMA drugs, these subtle designs are based on a deep understanding of the pathogenesis of the disease.
Therefore, the vigorous development of ASO drugs in the future will inevitably be accompanied by the continuous deepening of research on disease Biology.
In recent years, the development of precision medicine has continuously accelerated Biology research.
From the perspective of clinical efficacy, ASO drugs must first be able to meet the needs of patients for diseases, mainly for diseases that are difficult to treat with traditional drugs or difficult to make medicines, such as DMD, SMA and other diseases, and secondly, to reduce toxicity and increase efficiency as much as possible .
The chemical modification method can greatly reduce the stability of nucleases and avoid immune recognition, but there are still inevitably problems such as toxicity, lack of targeting, and low efficiency, resulting in some common side effects of current ASO drugs, and drug delivery systems It can greatly solve the problems that cannot be solved by chemical modification, and improve the effectiveness and safety of RNAi treatment.
Adding delivery systems to chemically modified ASO drugs has become a major trend in the development of ASO drugs.
For example, Ionis combines chemically modified ASO with GalNAc delivery system.
The most famous of these is Novartis’s acquisition in February 2019. Pelacarsen, a drug developed by Ionis for apolipoprotein a (APOa).
Lipoprotein a (Lp(a)) is a highly atherogenic lipoprotein similar to LDL.
It is connected to apolipoprotein a (Apo(a)) through disulfide bonds. Apo(a) is composed of LP(a). ) Gene coding.
Lp(a) has pro-inflammatory, pro-atherosclerotic and thrombotic properties, and has been confirmed by epidemiological studies to be related to myocardial infarction, stroke and peripheral artery disease.
The level of LP(a) has been determined at birth, and has nothing to do with the acquired lifestyle.
The current cholesterol-lowering drugs cannot be controlled. At present, there are about 8-10 million people in the world who have abnormal expression of LP(a).
Pelacarsen is an ASO drug conjugated with GALnac, which uses a full PS backbone and 2′-MOE modification to suppress Apoa mRNA and thereby LP(a) levels.
4. siRNA drugs-each part is unique
There are currently two siRNA drugs approved for marketing, namely Alnylam Patisiran for the treatment of haTTR and Givosiran for the treatment of acute hepatic porphyria (AHP).
Compared with ASO drugs, siRNA drugs are more difficult to ingest directly through cell membranes due to their larger volume and stronger hydrophilicity, and siRNA exposure to blood will cause stability problems and cause immunogenicity, so siRNA drugs without delivery systems are basically Unable to reach the ideal delivery level.
The two siRNA drugs currently on the market mainly use delivery systems that are more mature delivery technologies liposome (LNP) and GalNAc.
4.1 Patisiran-based on liposomal LNP, achieve zero breakthrough in siRNA drugs
LNP delivered siRNA The first successfully marketed drug was Alnylam’s Patisiran.
In August 2018, the FDA approved Alnylam’s RNAi drug Onpattro (generic name patisiran) for the treatment of nerve damage caused by transthyretin amyloidosis (haTTR).
Since the haTTR disease analysis has been analyzed in the previous introduction by Inotersen, we will not repeat it here.
As the first siRNA drug on the market, Patisiran reflects the evolution of Alnylam’s technology over decades, whether it is the modification technology of nucleic acid or the design of the delivery system, and each part can be described as unique.
4.1.1 Chemical modification of nucleic acids
Patisiran is a chemically synthesized double-stranded oligonucleotide. The sense strand and antisense strand each contain 21 nucleotides.
The 19 nucleotides of the sense strand hybridize with the complementary 19 nucleotides of the antisense strand to form 19 nucleotide base pairs, leaving two 3′-terminal nucleotides on each strand As an unhybridized overhang, Patisiran applied both 2′-OM and 2′-O-Me modifications. Moreover, the chemical modification of siRNA is more complicated than that of ASO.
The sequence of nucleic acid modification and the proportion of various modifications will also affect the stability and efficacy of the final drug.
Patisiran, as an siRNA drug developed earlier, uses a partial nucleic acid modification method, and has not yet used STC and ESC to modify the template.
From Patisiran to follow-up drugs such as revusiran (using STC) and Givosiran (using ESC) in the nucleic acid modification of siRNA, we can see the process of Alnylam’s accumulation of experience and technological improvement over the years.
From the perspective of the evolution of nucleic acid modification, even if Patisiran does not use the latest nucleic acid modification platform technology, it still guarantees a good effect.
The main reason is that there is not much room for improvement in nucleic acid modification itself, and the main focus is on improving stability.
In terms of attenuation and efficiency, compared with chemical modification, the improvement of delivery system may be more critical.
4.1.2 Liposome LNP delivery system
Patisiran is a chemically modified thyroxine (TTR) siRNA formulated in liposomes.
A key technology in Alnylam’s lipid nanoparticle (LNP) program in overcoming gene delivery barriers is to incorporate an optimized ionizable cationic lipid (DLIN-MC3-DMA) into the LNP-siRNA system. Or MC3).
Incorporating MC3 into the LNP-siRNA system can bring about efficient gene silencing.
Patisiran’s lipid components include DLin-MC3-DMA, DSPC, cholesterol and PEG-DMG, and the molar ratio is 50/10/38.5/1.5.
Cationic liposomes can effectively improve the therapeutic effect of gene therapy drugs.
The cationic liposome transfection complex has a positive charge on the surface, and the ionizable cationic lipid has a positive charge under low pH conditions (protonation of tertiary amine groups) (under physiological pH conditions, the cationic lipid shows Electrically neutral or low positive charge), adsorb to the surface of negatively charged cells through electrostatic interactions, and enter the endosome through endocytosis.
The pH in the endosome is reduced, which will lead to ionizable in the endosome The modified cationic lipids are gradually protonated and become positively charged.
The phospholipid bilayer of the human body uses anionic lipids, which will form a cone structure with cationic lipids in the body, thereby destroying the stable structure of the phospholipid bilayer.
Release nucleic acid drugs into the cytoplasm. Gene therapy drugs leave the cationic liposomes and enter the cells for transcription, translation, and expression of corresponding proteins.
4.1.3 Clinical efficacy
Patisiran’s approval is based on the results of a phase III clinical trial called APOLLO. This randomized, double-blind study included a total of 225 patients with amyloidosis, including 77 in the placebo group and 148 in the Patisiran treatment group.
The primary clinical endpoint of the study used the Neuropathy Injury Score (mNIS+7) system to assess the degree of neuropathy in patients, and the secondary clinical endpoint used Norfolk quality of life-diabetic neuropathy (Norfolk quality of life-diabetic neuropathy, Norfolk QOL-DN) survey method for evaluation.
The results show that compared with the placebo group, Patisiran’s treatment can effectively prevent nerve damage and improve the mNIS+7 score to a certain extent, while the nerve damage in the placebo group is further aggravated (Figure 1); at the same time, the Patisiran treatment group The patients were better than the placebo group in terms of exercise intensity, degree of disability, walking speed, nutritional status and autonomic symptoms.
In addition, the incidence of Patisiran’s adverse reactions and serious adverse reactions was comparable to that of the placebo group, indicating that Patisiran’s overall safety is good.
4.1.4 Patent situation
The patent problem of liposome delivery system has always been the biggest pain point of Alnylam using this delivery system.
Due to the lack of sufficient patent barriers on liposomes, Alnylam has never dared to concentrate on the development of liposome delivery systems.
Analyzing Patisiran’s patents, in addition to the design of nucleic acid sequences, the design of cationic lipids and the composition of LNP are mainly derived from Arbutus, which are not the independent intellectual property rights of Alnylam, and they have also been infringed by Silence’s patent in the European market.
Litigation and patent issues are also a major reason for Alnylam’s subsequent pipeline to abandon the use of liposomes.
In terms of cationic LNP patents, the general patent layout structure of companies in the miRNA field is generally: the parent case protects important lipid preparation active ingredients, divisional protection of the combination of lipid preparations and therapeutic siRNA, and the US patent application There is a patent period adjustment system, and big factories will use multiple patent applications to obtain different extension periods to a certain extent to extend the patent protection period for products.
Therefore, under the premise that Tekmira, the predecessor of Arbutus, has fully protected the MC3 liposome patent, it will be difficult to break through the cationic liposome patent barrier unless the cationic lipid design is greatly changed.
Therefore, Alnylam chose to take a different path and chose the GalNAc field with its own deep patent accumulation in the subsequent development of the miRNA pipeline.
4.1.5 Patisiran commercialization success
The good curative effect made Patisiran a commercial success. Although Patisiran is priced high and the annualized cost has reached 450,000 US dollars, its mature LNP process and sequence selection and modification technology have brought definite curative effects, which greatly meets the needs of patients for satisfaction, making this product in Q4 2018 After listing, it has achieved great success and maintained a rapid growth in sales every quarter.
4.2 Givosiran—GalNAc shines
In November 2019, Alnylam’s Givosiran was approved for marketing, becoming the world’s second RNAi drug, the first drug for the treatment of adult acute hepatic porphyria (AHP), and the first siRNA marketed with GalNAc coupling technology drug.
In addition, Givosiran uses enhanced stabilization chemistry (ESC)-GalNAc-siRNA conjugation technology to enhance the stability of the duplex to nucleases by ESC modification.
In addition, the hepatocyte-targeting ligand attached to the 3’end of the sense strand has 3 GalNAc splits, and the other three ends (5′ of the sense strand and 3′, 5’of the antisense strand) are on each side There are phosphorothioate bonds in the last two subunits. This combination (ESC-GalNAc-siRNA) has enhanced stability after subcutaneous administration of siRNA, and compared with standard template chemistry (STC), the potency of the drug is increased by 10 times.
4.2.1 GalNAc Delivery System
GalNAc is a ligand for asialoglycoprotein receptor (ASGPR). Asialoglycoprotein receptor (ASGPR) is an endocytic receptor that is highly specifically expressed on the membrane surface of liver cells (~500,000 /Cell), and almost no expression in other cells.
The endocytosis mediated by ASGPR and clathrin can effectively transport galactose-derived ligands from the cell surface to the cytoplasm. During this process, ASPGR appeared on the cell surface within 15 minutes.
Tetravalent and trivalent ligands show higher affinity than monovalent and divalent ASGPR. Therefore, the trivalent or tetravalent GalNAc moiety is covalently conjugated to the siRNA with a proprietary linker structure.
Currently, trivalent GalNAc is often used as the conjugate part.
The ability to administer subcutaneously in long cycles is a huge advantage of GalNAc. GalNAc-siRNA injected subcutaneously has better performance than GalNAc-siRNA injected intravenously.
The main reason is that siRNA used under the skin needs to pass through connective tissue, capillary and lymphatic endothelial cells to accumulate in the circulation.
This process changes the pharmacokinetic properties of GalNAc-siRNA.
Intravenous injection of siRNA will rapidly excrete from the circulatory system to the kidneys, and intravenous injection can achieve higher intrahepatic accumulation.
More importantly, GalNAc-siRNA conjugates show a very long time of action through enhanced stable modification chemistry (such as ESC or ESCplus), supporting these RNAi drugs can even be administered once every six months.
But GalNac also has many shortcomings. The sialoglycoprotein receptor (ASGPR) ligand not only confers high liver targeting on GalNac, but also limits its application fields, and GalNAc is often not the best choice for liver cancer.
4.2.2 Clinical efficacy
At the time of Givosiran’s approval, some observers expressed concern about the short duration of the drug in clinical trials and the questionable safety issues. However, in June 2020, Alnylam released long-term, open-label expansion data, eliminating doubts about the safety of the drug for long-term use.
According to the open-label expanded data of the Phase III ENVISION study published on June 30, during the one-year treatment period, Givlaari showed sustained efficacy in reducing the number of attacks in AHP patients, and there is evidence that over time, the efficacy Improved: Compared with placebo, Givosiran reduced the annualized rate (AAR) of compound porphyrin attacks (porphyrin attacks that require hospitalization, emergency treatment, or intravenous heme treatment at home) by 74% and the median AAR It is 1.0 times. During the study period, Givosiran showed acceptable safety and tolerability; the 12-month results showed that patients who continued to receive Givlaari during the open-label expansion period had a continuous decrease in AAR and a median AAR of 0.0.
4.2.3 Patent situation
GalNAc coupling occupies an important position in the drug development pipelines of several pharmaceutical companies. The most famous is Alnylam.
The main reason is that in addition to the good properties of GalNAc itself, it is also because Alnylam has a deep accumulation of patents in the GalNAc field.
It can be seen that in Alnylam’s Givosiran patent group, except for the nucleic acid chemical modification patents that are authorized by Ionis, almost all the remaining patents are owned by Alnylam himself.
Many other pharmaceutical companies such as Dicerna, Silent and Arrowhead are also developing GalNAc-conjugated miRNA products.
4.3 Inclisiran-Entering the field of chronic diseases
Inclisiran is an RNAi therapy under development to lower cholesterol. At the end of 2019, Novartis acquired The Medicines Company for US$9.7 billion to earn inclisiran.
This is the first time the drug has been approved for clinical use in China. Inclisiran is a fully chemically stable double-stranded RNA that targets the 3’UTR of PCSK9 mRNA.
Five types of modifications based on natural RNA were used to prepare this compound: phosphorothioate, 2′-deoxy, 2′-F, 2′-methoxy, and trivalent GalNAc.
4.3.1 Inclisiran mechanism of action
PCSK9 is a serine protease encoded by the PCSK9 gene, which is mainly produced by the liver. PCSK9 binds to the LDL receptor (LDL-R) on the surface of liver cells to degrade LDL-R, thereby reducing the ability of liver cells to clear LDL-C particles.
This leads to increased LDL levels in the blood. Studies have found that PCSK9 loss-of-function mutations can reduce LDL-C levels and significantly reduce the risk of cardiovascular events.
Conversely, gain-of-function mutations in PCSK9 increase LDL-C levels and the risk of cardiovascular events.
Therefore, inhibition of PCSK9 is a reasonable target for the treatment of cholesterol lowering LDL. Anti-PCSK9 drugs have quickly become a hot spot in the study of lipid-lowering therapy, and pharmaceutical companies have begun to study anti-PCSK9 drugs.
At present, the statin drugs used to lower LDL-C cannot be controlled for patients with severe hypercholesterolemia (such as familial hypercholesterolemia) and patients with statin intolerance, while the antibody drugs for PCSK9 face extreme challenges.
High cost or frequent dosing issues. Therefore, the use of innovative therapies to replace statin therapy or antibody combination therapy has become an urgent need to solve this popular cardiovascular disease.
Inclisiran is the first RNAi therapy to reduce LDL-C.
It can directly bind to the mRNA encoding the PCSK9 protein, and reduce the level of mRNA through RNA interference, thereby preventing the liver from producing PCSK9 protein.
Research has found that PCSK9 protein plays a role in the regulation of blood lipids.
It plays an important role, lowering its level allows more LDL receptors to return to the surface of liver cells, bind with more LDL, and clear them from the blood.
4.3.2 Inclisiran clinical efficacy
The study on the clinical efficacy and safety of Inclisiran is called ORION-11. In the key phase 3 clinical trial for lowering low-density lipoprotein cholesterol, Inclisiran reached all the primary and secondary endpoints of the trial, and showed good safety and Tolerance. After half a year, the subjects’ low-density cholesterol levels were still 47% lower than baseline.
In addition, the levels of other atherogenic lipids also decreased significantly, including lipoproteins decreased by 77%, total cholesterol concentration decreased by 55%, and apolipoprotein B decreased by 72%.
The success of this clinical trial demonstrates the potential of RNAi therapy in treating a large number of common diseases.
4.3.3 Inclisiran is significant
If Inclisiran is successfully approved, it will be another milestone for RNAi and small nucleic acid therapy.
It will herald the powerful potential of this new treatment model in the treatment of chronic diseases with a large number of patients, and because chronic disease drugs are safe in the long term Sexual requirements are higher, and the safety of small nucleic acid drugs will be verified again.
4.4 Summary of siRNA development
Compared with ASO, siRNA pays more attention to carrier technology due to its own nature. Although chemical modification can greatly reduce the stability of nucleases and avoid immune recognition, other problems still need to be solved, and the drug-carrying system can greatly solve the problems that cannot be solved by chemical modification and improve the effectiveness of siRNA treatment And safety, and partial targeting.
Therefore, although ASO companies have also begun to pay attention to the combination of ASO and carriers in recent years, siRNA platform technology companies still value the support of carrier technology platforms more than ASO. A good carrier technology will determine the success or failure of siRNA drugs.
At the same time, if Inclisiran is successfully approved, it indicates that siRNA will enter the market with great potential, but the field of chronic diseases with higher safety requirements also indicates that there will be higher requirements for the safety of delivery systems in the future, and this will also Become a major point of distinguishing enterprises.
Finally, judging from the current clinical results, the use of siRNA drugs does not conflict with traditional drugs and monoclonal antibody drugs, and the combination often has better effects, which will also help siRNA drugs in chronic diseases and cancer in the future. Rapid increase in other fields.
5. Stones from other mountains-leading foreign companies in the field of small nucleic acids
Small nucleic acid drugs have a clear tendency towards platformization:
- Whether it is a small molecule drug or a macromolecular monoclonal antibody, the molecules that bind to the target protein are based on a three-dimensional fit, which leads to a highly non-standardized drug screening process, sometimes with accidents. Luck component
- However, the screening of RNA drug sequences does not basically involve three-dimensional structures, but is performed on simpler DNA or RNA sequences;
- In principle, given any target sequence, the corresponding small nucleic acid sequence can be immediately given. Therefore, small nucleic acid drugs are more reproducible, and because nucleic acid drugs are platform-like in both chemical modification and delivery systems, both Companies with technological advantages are also more likely to produce platform effects.
Therefore, compared with small molecule drugs and monoclonal antibody drugs, the field of small nucleic acid drugs makes it easier for platform companies with technological advantages to come out, and companies that truly have core technology portfolios deserve attention.
5.1 Alnylam-Industry Adherent
On April 13, 2020, Alnylam (Nasdaq: ALNY), a Nasdaq listed company, announced that it has reached a strategic investment cooperation agreement with Blackstone.
Blackstone invested US$2 billion to support Alnylam’s RNAi project, becoming the largest single transaction in the biotech industry Private investment case.
Alnylam was established in 2002. The company mainly focuses on the four therapeutic areas of genetic diseases, liver infectious diseases, cardiac metabolic diseases and central nervous/ophthalmological diseases.
In the past 20 years, the company has also experienced ups and downs, and has undergone a series of strategic adjustments, especially when the industry’s overall capital ebb in 2012, the company was once unable to support it, implemented a strategic reorganization, and laid off about 33% of its employees.
After years of development, the company currently has two marketed products (Onpattro, Givlaari), and it is expected to obtain two new FDA-approved RNAi therapies before Q1 2021, and there are six late-stage clinical projects, and four major strategies The therapeutic area (Strategic Therapeutic Areas, STArs) has 14 clinical development projects.
After nearly 20 years of perseverance and accumulation, the company has accumulated profound accumulation in the chemical modification of small nucleic acids, nucleic acid sequence design and drug delivery systems, and has successively developed two RNAi drug delivery technologies, namely lipid nanoparticle delivery platforms ( LNP) and GalNAc-siRNA subcutaneous delivery platform, multiple nucleic acid modification technologies and multi-generation siRNA sequence template design technology.
Since it has been introduced in the previous article, I will not repeat it here.
The company is also developing other innovative RNAi technologies, including Bis-RNAi, which simultaneously targets two different mRNAs, and Reversir, which can quickly and specifically reverse the gene silencing effect of RNAi.
The development of these technologies will provide more possibilities for the RNAi technology platform.
Alnylam is highly efficient and has a very high success rate in the development of small nucleic acid drugs.
In terms of R&D, Alnylam predicts that from now to 2025, there will be 2-4 R&D projects in the company’s R&D pipeline each year that can submit IND applications.
Alnylam’s R&D project progressed from phase 1 to phase 3 clinical trials with a positive success rate of 54.6%, which is much higher than the industry average for new drug development.
This is because all research and development projects are based on human genetically verified targets, and the use of biomarkers is part of all research projects.
Once the challenges of side effects and delivery methods are overcome, the successful development of RNAi therapies becomes relatively simple.
At this time, the limiting factor in the development of RNAi therapy will become how to find a suitable target.
5.2 Ionis-a pioneer in the small nucleic acid industry
Ionis and its subsidiary Akcea can be said to be one of the leaders in the development of ASO therapy.
The company has used its proprietary antisense RNA technology to create a large pipeline of first-in-class or best-in-class drugs, with more than 40 drugs under development, and has reached strategic cooperation with many industry giants.
The company’s Spinraza is very effective in treating SMA patients, and Tegesedi, which treats haTTR, has also been approved by the FDA.
Today, the company has many years of cooperation projects with major pharmaceutical companies such as Biogen, Roche, AstraZeneca, Novartis, Janssen, and GlaxoSmithKline (GSK).
The disease areas targeted by the company’s ASO therapy include neurological diseases, rare diseases, cardiovascular and kidney diseases, and cancer.
In addition to working on the chemical modification and improvement of the nucleic acid of the ASO drug itself, in recent years Ionis has also been continuously developing the technology of combining the delivery system with ASO (LICA) to deliver larger doses of ASO to the required tissues and cells.
The most classic case is undoubtedly the cooperation between Ionis and Alnylam, which combines GalNAc with ASO, which increases the potency of the second-generation ASO on liver targets by about 30 times.
When combined with 2.5th-generation ASO, its effectiveness is about 10 times that of second-generation drugs.
Based on this success, the company cooperated with Astra-Zeneca to achieve therapeutic ASO concentration in pancreatic β cells by combining GLP-1 peptide with ASO.
5.3 Sarepta-deep plowing the field of DMD
Sarepta focuses on the treatment of patients with Duchenne’s muscular dystrophy (DMD) and gene therapy. Currently, many drugs have been approved.
The company’s technology platform uses phosphorodiamidate morpholino oligomers (PMOs) and exon treaty technology to allow pre-mRNA to skip mutated exons during translation, thereby producing functional defects that can alleviate DMD patients Of dystrophin.
The company’s PMO technology platform uses morpholine instead of ribose in RNA.
This substitution improves the stability of PMO while maintaining the normal binding of PMO to specific RNA sequences.
At present, the company has a number of PMO therapies for the treatment of DMD being tested in phase 3 clinical trials for the treatment of patients with mutations in different exons of the DMD gene encoding dystrophin.
Peptide phosphorodiamidate morpholino oligomers (PPMO) is Sarepta’s proprietary next-generation PMO-based therapy, under development, specifically designed to improve tissue permeability.
Through the connection of PMO and penetrating peptide, it can be targeted for delivery to skeletal muscle, heart and smooth muscle cells, which can improve delivery efficiency and reduce dosage.
In animal experiments, PPMO has shown good results.
5.4 Arrowhead-focus on active targeted delivery
Arrowhead is committed to developing treatments for refractory diseases by silencing disease-causing genes. Utilizing its extensive RNA chemical technology combination and effective delivery mode, it leads to rapid, deep and long-lasting knockdown of target genes, thereby affecting the production of the encoded protein.
The company’s RNAi technology patent was obtained on March 5, 2015, and the authorization came from Novartis.
At that time, Novartis had basically lost confidence after many failed clinical trials, and the license price was very low.
After obtaining the patent, the company updated the technology, and the current pipeline and progress appeared.
Arrowhead’s unique targeted RNAi molecular technology TRiM platform utilizes ligand-mediated delivery.
The TRiM system mainly targets high-affinity targeting ligands, various linkers and chemicals, and sequence-specific chemically modified nucleic acid sequences that can achieve tissue Specific targeted drug delivery while maintaining the structure of the siRNA molecule.
Targeted delivery is the core of Arrowhead’s development philosophy, and the TRiM platform is the positive result of the company’s more than ten years of targeted drug carrier research.
5.5 White Oak Group-a new liposome delivery system in the oncology field
The WhiteOak Group, Inc. is an emerging biotechnology company located in Rockville, Maryland, USA. The company focuses on the research of nucleic acid drugs and other lipid nanoparticle drug delivery technologies.
The company is led by industry experts such as Dr. DJ Kim and Dr. Robert J Lee, who have long-term research in the field of nucleic acid drugs, and has accumulated many years of accumulation in drug delivery technology in the field of oncology. Its innovative technology platforms include three platforms: QTsomeTM for nucleic acid delivery, long-circulating liposome PEGsome, and Deposome for subcutaneous delivery.
Among them, QTsome has been used in the development of nucleic acid drugs for tumor-related targets such as AKT-1, HIF-1a, miR21, PEGsome has been used in the development of many drugs, and DepoSome has been used for sustained-release drug delivery in areas such as postoperative analgesia Development.
It is particularly worth mentioning that the company’s QTsome technology cleverly uses base buffer pairing technology to establish unique intellectual property protection. It is unique in the crowded LNP field and has a number of global authorization columns. It is also used in primary liver cancer, A number of clinical and preclinical verifications have been carried out in areas such as small cell lung cancer.
According to public literature, its drug delivery system has relatively high safety, high nucleic acid drug encapsulation rate, and related processes and excipients have achieved cGMP related verification requirements, laying a solid foundation for phase II/III clinical sample supply and commercial production basis.
~~~~ miRNA (microRNA) drugs: Status Trends Technology ~~~~
~~~~ miRNA (microRNA) drugs: Status Trends Technology ~~~~
(source:internet, reference only: miRNA (microRNA) drugs: Status Trends Technology)
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