22. Spinraza

Biogen headquarters

Active ingredient: Nusinersen
Disease: spinal muscular atrophy
Peak sales estimate: $2.5 billion
Approved: Dec. 23
Company: Biogen/Ionis

The scoop: Analysts didn’t see Spinraza getting approval until mid-2017, but the FDA pulled through at the eleventh hour, making Biogen and Ionis the first to market with a treatment for spinal muscular atrophy. The disease is caused by a mutation in the survival motor neuron gene 1 (SMN1). This blocks production of the SMN protein, which is crucial in maintaining motor neurons, the nerve cells responsible for controlling muscle movement. It affects one in 10,000 babies and is often fatal, causing weakness and muscle wasting. Spinraza snagged orphan drug and fast-track designations as well as priority review. It works by amplifying the SMN2 gene to boost production of the SMN protein. In a phase 3 study, it demonstrated significant improvement in motor function compared to untreated patients. -- Amirah Al Idrus

22. Spinraza