FDA approves SMA gene therapy

The FDA has approved Novartis’s onasemnogene abeparvovec, a gene therapy for children less than 2 years of age with spinal muscular atrophy (SMA). SMA is a rare genetic disease caused by

mutations in the survival motor neuron 1 (_SMN1_) gene, leading to motor neuron death and often fatal muscle weakness. In 2016, the FDA approved Biogen’s antisense drug nusinersen for

injection four times a year to modulate the splicing of _SMN2_ and thereby to boost production of the compensatory protein. Onasemnogene abeparvovec now provides a one-time adeno-associated

virus vector-based gene therapy that inserts a functional copy of the _SMN1_ gene into motor neurons. In ongoing and completed trials, patients on onasemnogene abeparvovec showed significant

improvements in their ability to reach developmental motor milestones compared with the infantile-onset SMA natural history. Onasemnogene abeparvovec will cost more than US$2 million,

drawing attention as the world’s most expensive therapy. Novartis has argued that the gene therapy is cost-effective compared with the standard of care, and will let payers spread payments

out over 5 years. The gene therapy has been praised as a worthwhile and welcome advance by some. Others have flagged the price tag as a sign of out-of-control and unsustainable drug pricing.

Peak sales could reach $1.8 billion in 2022, show consensus sales forecast data from Clarivate Analytics’ Cortellis database. Novartis bought gene therapy company AveXis for $8.7 billion

last year, in part for onasemnogene abeparvovec but also to expand its advanced cell therapy capabilities. Novartis has also licensed the rights to develop and commercialize Spark

Therapeutics' gene therapy voretigene neparvovec, for an inherited form of blindness, outside the United States. And in 2017, it secured the first ever approval for a chimeric antigen

receptor T cell therapy, tisagenlecleucel for acute lymphoblastic leukaemia.