October 2019 marked a milestone for modern genetic medicine. A leading Swiss drug maker registered USD 160 million of quarterly sales for the world's most expensive drug – Zolgensma – a gene therapy priced at USD 2.1 million. It proved that, despite lofty treatment costs, there is strong demand for gene therapies that offer a one-time cure for disease: in the case of Zolgensma, for a rare condition called spinal muscular atrophy.
The four existing gene therapies available worldwide are set to register combined sales of USD 1 billion on an annualized basis in 2019-2020. With 90 more gene therapies in the pipeline, we believe the gene therapy market has a potential value of USD 20 billion, or around 2% of global biopharma sales.
The current science of gene therapy is limited to the treatment of rare monogenic diseases – mostly forms of blood cancer, inherited retinal dystrophy, and muscular atrophy. However, if and when genetic therapies can progress to treat hard tumor cancers and even chronic diseases like diabetes, they have the potential to drive a major paradigm shift in modern medicine.
This year's milestone event comes after years of investment and a number of false starts where expensive genetic therapies for small patient communities failed commercially. The success of existing gene therapies is partly down to innovative insurance coverage by commercial and state insurances, but also the willingness of patients to pay up for a one-time cure for a lifelong or hitherto "incurable" disease.