First ever RNA-based gene-silencing drug approved by FDA, and it's not cheap

Twenty years after the breakthrough discovery illustrating how RNA interference can be used to silence certain genes, and over a decade after the research won a Nobel prize, the U.S. Food and Drug Administration has approved the first drug utilizing this method for adult clinical treatment. The condition, hereditary transthyretin-mediated amyloidosis (hATTR), is rare and the drug is not a cure but rather an ongoing treatment that will reportedly cost up to US$450,000 per year for a single patient.

RNA molecules are like the messengers that carry instructions from our DNA, directing our body to produce certain proteins. The idea behind RNA interference is that small molecules can be developed to neutralize these RNA messengers, effectively silencing the expression of certain genes that could be causing harmful health effects. These disruptive molecules are called small interfering RNAs (siRNAs).

Development of these siRNA clinical treatments has been slower than initially hoped, with researchers spending the better part of the last two decades searching for effective ways to both deliver these molecules to specific target organs and producing nanoparticles that can shield the siRNA from degradation while it its moving through the bloodstream.

The latest FDA approval for the siRNA drug is groundbreaking but incredibly narrow, focusing on a rare condition that only afflicts around 50,000 people worldwide. The drug is called Onpattro (patisiran), and it disrupts the RNA mechanism producing transthyretin, a protein that promotes an accumulation of amyloid deposits in the body. The FDA approval only specifies the new drug as treatment for symptoms of peripheral nerve disease (polyneuropathy), caused by hATTR in adult patients. The disease is also known to cause a decline in cardiac functioning.

Alnylam, the company behind the development of Onpattro, currently has three more siRNA drugs in late-stage trials, and the hope is to have those treatments approved within the next one to two years. Alongside the FDA approval, the EU is set to pass Onpattro for public use very soon.

Tempering the excitement of this breakthrough new drug hitting the market is the price that it has been listed for. The treatment involves infusions every few weeks, and the current list price for one year's treatment is suggested to be US$450,000. The company has claimed it will offer insurers a reimbursement system if the drug does not work in certain patients, and Barry Greene, President of Alnylam, is reported as saying this overall cost would be less than what the patient would cost an insurer in a given year without the new drug.

Unlike some similarly priced new gene therapies revealed last year, what stands Onpattro apart is that it is not a curative agent but rather an ongoing treatment, that presumably will need to be maintained indefinitely. Last year's breakthrough cancer-killing treatment Kymriah, was priced at around $475,000, but it was essentially a singular curative treatment. A one-off cost of half a million dollars for a cure is certainly a different proposition than an ongoing treatment that will cost hundreds of thousands of dollars a year.

Of course, there are many incredibly expensive treatments already out in the world costing patients hundreds of thousands of dollars a year, so this new siRNA drug isn't a major outlier. But, it may be the shape of things to come with more and more new, innovative drugs to hit the market over the coming years. Each of these drugs will have come from years of costly research and inevitably will have price tags to match.

Source: FDA