Antisense: Revolutionary Drug Therapy

Late last summer the United States Food and Drug Adminstration approved the FIRST antisense-based drug (fomivirsen) for the treatment of retinitis caused by Cytomegalovirus (CMV) infections in AIDS patients. Retinitis is the inflammation of the retina in a person's eye. This viral retinitis can in a fairly short time make the person blind.

About 80 percent of all adults have CMV in their bodies. Usually, our body's immune system prevents the virus from causing any problems. However, if for some reason, our immune system is severely weakened, then CMV can cause serious diseases. This is often seen in AIDS patients.

Two other drugs (ganciclovir and cidfovir) have been used to treat this CMV retinitis however not all patients can tolerate the drugs. Fomivirsen (the new anti-sense drug) is a single strand of DNA that binds to the messenger RNA (mRNA) inside our cells. The mRNA is a copy of the virus DNA present in the nucleus of the cell. The mRNA message is then translated (converted from RNA to protein) to protein. However, if the antisense-drug is present it covers up the mRNA and does not allow the cell to make viral protein. If no viral proteins are made then no more new viruses are produced and as a result no more damage occurs to the person's retina.

So far fomivirsen has been shown to be safe to use in humans. It is injected into the eye of the patients and it has been shown to be very effective in preventing blindness due to CMV.

This is a major new mode of treating viral infections and hopefully similar drugs can be developed to help others with different viral diseases. This type of drug may also be useful in treating cancer, Crohn's disease, renal transplant rejection, and rheumatoid arthritis.

Knowledge is power. For more power go to:
The CIBA vision Corp for information on this drug.
To find out more on how antisense works go to Hybridon's site. To see the animation you will need shockwave. The animation is really worth the time to get shockwave on your computer.

Take Care and Think Microbiologically!

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