Competing in gene therapy is unlikely to follow the same rules as competing in other therapeutic categories where - even in Orphan diseases - a better product can steal market share. The reason is that if the first gene therapies to market deliver on the promise of a functional cure, there may not be any patients left to treat.
Investors have poured at least $3 billion into 20 companies developing gene therapies for Orphan indications that have one or more competitors working on the same gene - including $1 billion to bluebird bio Inc. alone. Most of these companies have touted potential benefits of their products over more advanced competitors targeting the same genes.
But in Orphan indications, if the first-to-market therapy addresses a large proportion of the prevalent patient population, it could be difficult for followers to even enroll clinical trials. And it is unknown whether the risk of immunogenicity to the vector or the transgene protein product would preclude re-treating patients who received a first-generation product.
"If there is an approved gene therapy that is providing a functional cure, I think it will be hard for some of these companies to enroll trials," Spark Therapeutics Inc. CFO Stephen Webster told BioCentury.
However, when the gene therapy delivers a therapeutic protein that doesn't address the underlying pathology of the disease - and therefore isn't a cure - improvements in efficacy or safety can potentially supplant first-in-class therapies.
And even in Orphan indications, there could be room for followers with new vectors if the first to market uses a vector to which a large enough proportion of the population has a pre-existing, natural immunity.
For companies pursuing larger indications, the rules