Antisense Drugs

Our antisense-based drug discovery platform is a rapid and efficient route to capitalize on new insights in genomic information to make novel drugs. Using this platform, we make drugs that specifically address disease targets, many of which are otherwise “un-druggable” by other methods. In this way, we can maintain a robust pipeline of first-in-class or best-in-class drugs to treat a broad range of diseases.

Antisense drugs are small (12-25 nucleotides) DNA- or RNA-like compounds that are chemically modified to create drugs. The core of antisense technology is therefore the chemistry of antisense drugs. We continue to make significant advances in our core chemistries, enhancing the properties of our drugs.

Distribution and Clearance

Antisense drugs are rapidly and effectively absorbed. In the blood, antisense drugs bind loosely to proteins. This binding facilitates the distribution of antisense drugs to tissues and prevents immediate loss in urine. Distribution to tissues occurs via a shuttling process that involves proteins. In tissues, the drugs are cut by enzymes called endonucleases. After being cut by endonucleases, the drugs may be further degraded by exonucleases. The partial drug molecules do not bind to proteins and are therefore cleared in the urine.


Like all drugs, antisense drugs can have side effects. The side effects are generally predictable, occur at high doses and are well understood. More than 10,000 humans have been safely treated in trials conducted by Ionis and its partners.

Drugs in Development

We are the leader in antisense drug development with a broad portfolio of drugs that are applicable to many different diseases. While we can develop an antisense drug to almost any gene, we focus our efforts on developing drugs to targets where our drugs will work best, efficiently screening many targets in parallel and carefully selecting the best drugs. This efficiency combined with our rational approach to selecting disease targets enables us to build a large and diverse pipeline of drugs designed to treat patients with health conditions, including severe and rare/neurodegenerative diseases, cardiovascular, metabolic, cancer, inflammatory, and ocular.

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