Spinal muscular atrophy
Spinal muscular atrophy (or SMA) includes loss of motor neurons in the spinal cord and lower brain stem, which leads to severe and progressive muscular atrophy and weakness. Patients suffering from severe SMA can become paralyzed.
The total worldwide sales of Biogen’s (BIIB) Spinraza increased from $47.4 million in 1Q17 to $363.9 million in 1Q18. The US sales of the drug increased from $46.4 million in 1Q17 to $188 million in 1Q18. Spinraza’s rest of the world sales increased from $1 million in 1Q17 to $175.9 million in 1Q18.
In fiscal 2016, Spinoza generated sales of $4.6 million. In fiscal 2017, sales rose to $883.7 million. Biogen expects the growth rate of the drug to moderate over time as patients transition to dosing every four months.
Approvals and drug profile
Spinraza was approved by the U.S. Food and Drug Administration (or FDA) for the treatment of SMA in pediatric and adult patients in December 2016. Biogen presented phase three end of study data in April 2017, which showed a significant improvement in motor function in children with later onset of SMA as compared to untreated children. These findings continued to support the efficacy and favorable safety profile of the drug for a broad range of individuals with SMA.
Spinraza is the first approved treatment for SMA in the European Union (or EU). Reviewed under the accelerated assessment program, the drug received marketing authorization in the EU in June 2017. Further, the drug also received approval in Japan in July 2017 to treat infantile SMA and in September 2017 for treating pediatric and adult patients with SMA.
In the next part of the series, we’ll analyze why Biogen withdrew Zinbryta from the market.