

How Biotech Companies Are Targeting RNA to Cure Diseases

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Courtesy of Translate

Amid the excitement and debate over gene therapies like Novartis ’s Zolgensma and Bluebird Bio ’s Zynteglo, it’s easy to lose sight of the other cutting-edge approaches that biotech companies are taking to tackle disease.

For a number of biotech companies, the key to curing disease isn’t at the DNA level, where the gene therapy players focus, but in the RNA, the step in gene expression that lies between the DNA and the cell’s protein factories.

In the cover story this weekend, Barron’s laid out the debate around messenger RNA therapeutics, or mRNA, one of the approaches in this categories.

But mRNA is only one of a bewildering number of new drug development approaches to work with RNA. Some of these modalities have already led to drugs that are on the market. Others, like the mRNA therapeutics being pursued by Moderna (ticker: MRNA) and Translate Bio (TBIO), are still in the clinical stage.

Here is a brief primer on some of the other ways that biotech companies are targeting RNA to cure diseases:

RNA Interference

RNA interference, or RNAi, can shut down the expression of targeted harmful genes. Alnylam Pharmaceuticals (ALNY) received Food and Drug Administration approval in August 2018 for its drug Onpattro, the first RNAi drug to hit the market. And in October of last year, Johnson & Johnson (JNJ) announced a deal to develop and sell an experimental RNAi drug developed by Arrowhead Pharmaceuticals (ARWR) that targets hepatitis B.


Antisense drugs shut down the production of harmful proteins by binding to and destroying messenger RNA. Ionis Pharmaceuticals (IONS) sells a number of antisense drugs, including Spinraza, which treats spinal muscular atrophy. Sarepta Therapeutics ’s (SRPT) Exondys 51, which treats Duchenne muscular dystrophy, is also an antisense drug.


This approach focuses on microRNA, small RNA molecules that naturally regulate gene expression. In 2018, the biotech company Regulus Therapeutics (RGLS) handed over development responsibilities for a microRNA drug targeting Alport syndrome to Genzyme, a subsidiary of Sanofi (SNY).


This approach is similar to RNAi, except that it up-regulates gene expression, whereas RNAi down-regulates. The private London-based biotech MiNA Therapeutics is testing an saRNA drug in advanced liver cancer.

Nonsense Mutations

PTC Therapeutics (PTCT) sells a drug called Translarna, a small molecule drug that allows the ribosome of a cell to ignore so-called nonsense mutations in mRNA that would otherwise keep the ribosome from building the relevant protein. Translarna treats Duchenne muscular dystrophy, and is approved by European Union regulators.

Write to Josh Nathan-Kazis at josh.nathan-kazis@barrons.com