The pharmaceutical company behind a gene therapy for inherited blindness has announced the product’s price, and sticker shock has sent news outlets worldwide into a collective tizzy.

Spark Therapeutics plans to charge $425,000 per eye for the therapy, called Luxturna, making it the most expensive drug ever marketed in the US. 

The landmark FDA approval of Luxturna in December 2017 represented the first approval of a gene therapy for an inherited condition, and only the third-ever approval of a gene therapy. 

Luxturna, which is administered as a one-time injection in the eye, uses modified virus particles to introduce a functional copy of the RPE65 gene into cells in the retina. A mutation in this gene causes specific cells that register light to malfunction, leading to irreversible and progressive vision loss that typically onsets in childhood or early adulthood. However, these mutations account for only a small subset of blinding diseases; it is estimated that between 2,000 to 3,000 Americans are candidates for Luxturna.

Though disease progression may be unequal between eyes, both will eventually lose vision, meaning that most patients will need injections in both eyes. How patients and their insurance companies will foot an $850,000 bill has incited debate between pharmaceutical industry leaders and patient advocate groups.

Some industry analysts predicted the drug's cost would actually be higher, due to its innovative status and the high costs invested during the 25 years of research and development.

“We felt that you could easily value this in excess of a million dollars”, Marrazzo said at an event prior to the announcement. 

David Mitchell, president of Patients For Affordable Drugs, countered this, telling NBC News: “Spark Therapeutics is charging as much for Luxturna as they think they can get away with.”

Spark stated that they are establishing contracts to sell Luxturna to specialty pharmacy distributors in order to enable a lower cost than the current model of purchasing treatments from a hospital or clinic.

Additionally, the company will offer a rebate program wherein insurance companies will be refunded an undisclosed percentage of the cost if patients do not respond to the drug. Hopefully, this will incentivize insurance companies to cover the injection. Discussions are underway with the Centers for Medicare and Medicaid Services to facilitate access to the drug for limited income patients. 

“Over these past few months, we have been working with health insurers to create innovative pathways for access to Luxturna that may serve as models for other one-time administered gene therapies in the future,” said Spark CEO Jeffrey Marrazzo in today's statement.  

Setting money aside, clinical trials demonstrated impressive efficacy. Subjects in a phase 3 study experienced dramatic improvements in vision after receiving treatment. Visual status was assessed by their ability to navigate an obstacle-filled maze under different lighting conditions.

Prior to receiving Luxturna, no patient could complete the maze at a lighting level of 1 lux – analogous to a night with a full moon. At one year, 65 percent of subjects (who would have progressed to complete blindness without intervention) could complete the maze under this low-light setting. The treatment also showed durability over time, as patients maintained their visual gains for up to 3 years.

Data from this trial, paired with emotional testimony by participants, helped secure a unanimous vote in favor of approval from an FDA panel.