The Promise of RNA Interference (RNAi) Therapies: Revolutionizing Medicine

RNA interference (RNAi) therapies represent a revolutionary paradigm in medicine, offering innovative ways to manipulate gene expression for therapeutic purposes. The ability to selectively silence or downregulate specific genes has opened new avenues for treating a myriad of diseases.¹

Understanding RNA Interference

RNAi is a natural cellular process that regulates gene expression. It involves the introduction of small RNA molecules, typically short interfering RNA (siRNA) or microRNA (miRNA), to target and inhibit the expression of specific genes. This elegant mechanism has garnered immense interest in the scientific community for its potential to address the root causes of various diseases at the genetic level.¹

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Development of RNAi Therapies

The journey from the discovery of RNAi to the development of therapeutic interventions has been both challenging and rewarding. Researchers have harnessed the power of RNAi to design drugs that can selectively modulate gene expression, providing a more precise and targeted approach to treatment.

Recently approved by the FDA, a set of innovative RNA interference (RNAi)-based therapeutics include:

• Patisiran (Onpattro; Alnylam), a treatment for hereditary transthyretin-mediated amyloidosis
• Givosiran (Givlaari; Alnylam), a treatment for acute hepatic porphyria
• Lumasiran (Oxlumo; Alnylam), a treatment for primary hyperoxaluria type 1
• Inclisiran (Leqvio; Novartis), a treatment for primary hypercholesterolemia
• Vutrisiran (Amvuttra; Alnylam), a treatment for hereditary transthyretin-mediated amyloidosis
• Nedosiran (Rivfloza; Novo Nordisk), a treatment for primary hyperoxaluria type 1

These siRNA drugs exhibit selective actions on specific mRNA transcripts, representing a significant advancement in combatting various diseases.¹

Zilebesiran, a promising example of an RNAi therapeutic in clinical trials, has shown efficacy in treating conditions such as hypertension. By specifically targeting the expression of liver-expressed angiotensinogen (AGT), zilebesiran disrupts the production of angiotensin II, a key player in blood pressure regulation.^2,3

Other siRNA-based therapies currently under development include therapies for hemophilia A and hemophilia B (fitusiran; Sanofi); a prophylactic treatment for acute kidney injury in individuals undergoing transplantation or post cardiovascular surgery (Teprasiran; Quark Pharmaceuticals); nonarteritic anterior ischemic optic neuropathy and primary angle glaucoma (Cosdosiran; Quark Pharmaceuticals); as well as ocular pain and dry eye disease (Tivanisiran; Sylentis).⁴

Applications Across Medical Fields

RNAi therapies have demonstrated versatility in their applications across various medical fields, ranging from oncology to genetic disorders and infectious diseases. In oncology, RNAi can be used to target and silence specific genes associated with tumor growth, offering a potential avenue for cancer treatment. In genetic disorders, RNAi may provide a way to address the underlying genetic mutations responsible for diseases.^4,5

In infectious diseases, RNAi can be employed to inhibit the replication of viruses by targeting their RNA genomes. The adaptability of RNAi therapies makes them a promising tool for precision medicine, allowing tailored treatments based on an individual's genetic makeup.^4,5

Challenges and Future Prospects

Although RNAi therapies hold immense promise, several challenges remain to be addressed. Delivery methods, off-target effects, and the potential for immune system activation are among the hurdles that researchers are actively working to overcome. Additionally, ensuring the long-term safety and efficacy of RNAi therapies in diverse patient populations is a crucial aspect of their development.⁶

Looking ahead, the future of RNAi therapies is marked by the potential for personalized medicine. As our understanding of the human genome advances, RNAi can be tailored to address individual genetic variations, paving the way for highly targeted and effective treatments. Ongoing research and clinical trials will continue to unravel the full potential of RNAi therapies and expand their applications across a spectrum of diseases.^6,7

Conclusion

RNAi therapies have emerged as a transformative force in modern medicine, offering a powerful means to intervene at the genetic level for therapeutic purposes. With ongoing advancements, these therapies are poised to redefine treatment strategies, providing targeted and personalized approaches to address a wide array of diseases. As the field of RNAi continues to evolve, the prospect of unlocking the full potential of genetic medicine beckons, promising a new era of precision and efficacy in health care.

References

1. Traber GM, Yu AM. RNAi-Based Therapeutics and Novel RNA Bioengineering Technologies. J Pharmacol Exp Ther. 2023 Jan;384(1):133-154. doi: 10.1124/jpet.122.001234. Epub 2022 Jun 9. PMID: 35680378; PMCID: PMC9827509.

2. Desai AS, Webb DJ, Taubel J, et. al. Zilebesiran, an RNA Interference Therapeutic Agent for Hypertension. N Engl J Med. 2023 Jul 20;389(3):228-238. doi: 10.1056/NEJMoa2208391. PMID: 37467498.

3. Zhang MM, Bahal R, Rasmussen TP, Manautou JE, Zhong XB. The growth of siRNA-based therapeutics: Updated clinical studies. Biochem Pharmacol. 2021 Jul;189:114432

4. Hokaiwado N, Takeshita F, Banas A, Ochiya T. RNAi-based drug discovery and its application to therapeutics. IDrugs. 2008 Apr;11(4):274-8. PMID: 18379962.

5. Zhu Y, Zhu L, Wang X, Jin H. RNA-based therapeutics: an overview and prospectus. Cell Death & Disease. 2022;13(7):1-15. doi:https://doi.org/10.1038/s41419-022-05075-2.‌

6. Alshaer W, Zureigat H, Al Karaki A, et al. siRNA: mechanism of action, challenges, and therapeutic approaches. Eur J Pharmacol. 2021;916:174178.

7. Friedrich M, Aigner A. Therapeutic siRNA: State-of-the-Art and Future Perspectives. BioDrugs 36, 549–571 (2022). https://doi.org/10.1007/s40259-022-00549-3