Alnylam Reports Successful Gene Drug Test

Researchers working on behalf of Alnylam Pharmaceuticals(ALNY - Cramer's Take - Stockpickr) reported Friday that a drug designed to turn off a gene responsible for disease did just that in patients infected with a serious respiratory virus.

In a small pilot study, the drug, ALN-RSV01, was able to reduce the amount of virus found in patients purposefully infected with the Respiratory Syncytial Virus (RSV) by 38% compared to patients treated with a placebo.

Alnylam says this study is the first scientific proof in humans that a so-called RNAi therapeutic can target a disease, although company officials acknowledge that this is a small study and much more work needs to be done before ALN-RSV01 is proven to be truly effective.

Complete data from this study, dubbed GEMINI, are being presented this weekend at a medical meeting in Singapore. Alnylam previously announced in January that the study was positive.

RNAi is a natural process of gene silencing in cells -- think of it as a genetic switch that when turned off, tells the body to stop making a certain protein.

Companies like Alnylam are working to develop new drugs -- dubbed RNAi therapeutics -- that would mimic this natural process. These drugs potentially work by silencing specific messenger RNAs that are responsible for making disease-causing proteins. By preventing the disease-causing protein from being made, you can potentially stop or cure the disease.

ALN-RSV01 is designed to turn off a gene responsible for the replication of the virus causing RSV, a serious lower and upper respiratory infection that typically inflicts young children and older adults with compromised immune systems.

There is no currently approved treatment for RSV. Medimmune, a biotech firm now owned by AstraZeneca(AZN - Cramer's Take - Stockpickr), does market Synagis, a billion-dollar drug that is used as a prophylactic to treat premature infants at risk for RSV. Synagis, however, is not able to cure infected patients, which is something Alnylam hopes ALN-RSV01 can do.

In the GEMINI study, 88 healthy patients were infected with RSV in their nasal passages. The patients were then randomly assigned to receive either ALN-RSV01 or placebo, also intra-nasally, starting two days before being infected with RSV and continuing for three days after infection.

Results from this trial showed that the ALN-RSV01 patients experienced a 38% reduction in infection rate compared to those patients given a placebo, measured by a various tests designed to record the amount of RSV present in the nose. This reduction in antiviral activity was statistically significant, says Alnylam.

Treatment with ALN-RSV01 also resulted in a 95% increase in the number of patients who remained free of infection. 12 of 42 placebo patients remained RSV-free after being infected, compared to 24 of 43 patients treated with ALN-RSV01.

Alynlam President Barry Greene says the company is most excited about the results of the GEMINI study because it validates the RNAi approach to treating disease and will allow the company to move ahead with further clinical studies of ALN-RSV01.

While the GEMINI data are positive, they are limited in scope. For instance, patients were infected and treated in their nose. RSV, however, only becomes a serious infection when it enters and affects the lungs. This study was not designed to show that ALN-RSV01 could enter the lungs enough to reduce the level of virus there.

Moreover, there was no change in the clinical symptoms between patients treated with ALN-RSV01 or placebo in this study. Ultimately, to be approved, ALN-RSV01 will have to show in large clinical trials that it can reduce the symptoms or effects of RSV infection, such as decreasing the number of days a patient must be hospitalized.