Six months after the FDA approved Spinraza (nusinersen) to treat children and adults with spinal muscular atrophy (SMA), the European Commission (EC) has also approved the drug for 5q SMA.
SMA is a genetic condition that leads to a deficiency in the spinal motor neuron (SMN) protein as a result of mutations of the survival motor neuron 1 (SMN1) gene. The severity of SMA correlates with the amount of SMN protein. 5q SMA represents approximately 95% of all SMA cases and refers to the locus (5q13.2) on the SMN1
gene where the mutations are present.
Generally, the muscles most affected in SMA patients are those near the shoulders, hips, thighs and upper back. Muscles used for breathing and swallowing may also be affected. The life expectancy for those born with early-onset SMA is less than 2 years.
Nusinersen is an antisense oligonucleotide designed to alter the splicing of pre-mRNA from the SMN2
gene in order to increase production of fully functional SMN protein.
While the FDA’s approval was based on interim data from 1 clinical trial (ENDEAR), the EC review had 2 clinical trials to assess the drug’s efficacy and safety: the ENDEAR study (early-onset SMA) and the CHERISH study (later-onset SMA). Data from both studies were presented at the American Academy of Neurology (AAN) annual meeting in April.1-3
In the ENDEAR study, infants (< 7 months of age) with SMA were given intrathecal nusinersen (12-mg scaled equivalent dose), or sham-procedure and at the conclusion, there was a significantly greater proportion of nusinersen-treated motor milestone responders versus sham-control (51% versus 0%; P
In the CHERISH study, children aged 2-12 years with later-onset SMA were given Nusinersen [ 4 intrathecal injections (totaling 12mg non-scaled)] or a sham procedure. Patients were monitored over 15 months, with a primary endpoint of change in Hammersmith Functional Motor Scale–Expanded (HFMSE) score at month 15 that demonstrated a treatment difference of 5.9 points in the mean change from baseline to Month 15 in the HFMSE score (P
SMA Community Elated
In a news release
, researchers and advocates seemed please with the news of the approval in Europe.
"This is a landmark day for the European SMA community. The approval of Spinraza to treat a broad range of patients with SMA provides patients currently living with SMA hope for disease stabilization or improvement. Further, I am encouraged that the approval of Spinraza may demonstrate the potential of other antisense oligonucleotides to treat more neurodegenerative disorders," Eugenio Mercuri, MD, Università Cattolica del Sacro Cuore, Rome, Italy.
"The approval of Spinraza by the European Commission is a triumph for our community. Patients and families affected by SMA in Europe may now have a brighter future than before Spinraza was available. We are grateful for the perseverance of the European SMA community as we waited for this day, and for the rigorous clinical work that resulted in a broad label that may offer access to many patients in Europe," said Joanna Mitchell, CEO of SMA Trust.
"We would like to convey our gratitude to the patients, families, physicians and their teams in the EU who participated in our clinical trials. Their support and dedication have been critical in achieving this important milestone," said B. Lynne Parshall, chief operating officer at Ionis Pharmaceuticals. "In the U.S., the initial launch of SPINRAZA is off to a strong start and we continue to be pleased with the dedication, passion, and commitment of our partners at Biogen. We are pleased that this approval makes Spinraza widely available in the EU to treat a broad range of people with SMA."
Kuntz N, Farwell W, Zhong ZJ, et al. Nusinersen in Infants Diagnosed with Spinal Muscular Atrophy (SMA): Study Design and Initial Interim Efficacy and Safety Findings from the Phase 3 International ENDEAR Study. Presented at the AAN 2017 Annual Meeting; Boston, MA; April 22-28, 2017. Abstract 002.
Schneider E, Mignon L, Su J, et al. Nusinersen in Symptomatic Children with Later-onset Spinal Muscular Atrophy (SMA): Design of the Phase 3 CHERISH Study. Presented at the AAN 2017 Annual Meeting; Boston, MA; April 22-28, 2017. Abstract 184.
Mercuri E, Finkel R, Kirschner J, et al. Efficacy and safety of nusinersen in children with later-onset spinal muscular atrophy (SMA): interim results of the phase 3 CHERISH study. Presented at the AAN 2017 Annual Meeting; Boston, MA; April 22-28, 2017.