Biogen has revealed promising preliminary data for tofersen, a potential treatment for the fatal neurodegenerative disease amyotrophic lateral sclerosis (ALS).
The drug is another antisense therapy derived from Biogen’s alliance with Ionis, and if approved would add to the partners’ existing rare disease treatment with a similar mechanism, Spinraza.
Tofersen is being developed for ALS patients who carry the SOD1 mutation, which accounts for just 2% of ALS cases, but nevertheless plays an important part in the drug’s mechanism.
Tofersen binds to the SOD1 mRNA, which then dismantles and reduces its protein production, which could decrease the toxicity associated with the mutant SOD1 gene and therefore improve survival.
It still has quite a way to go until it reaches market however, but it could be potential goldmine for Biogen if it does.
Awareness of ALS went global five years ago when campaigners sparked a viral internet craze via the Ice Bucket Challenge. Patients with the condition currently have virtually no treatments which can slow or stop the disease: the only currently marketed drug for ALS is riluzole, but this has limited efficacy.
“ALS is a devastating disease and there are currently no therapeutic options that reliably slow or halt its rapid progression,” said Merit Cudkowicz, co-principal investigator and the director of the Healey Center at Massachusetts General Hospital.
“We are encouraged by the positive results of this phase 1/2 study of tofersen in patients with SOD1-ALS and are excited to advance this clinical programme to a phase 3 trial to further investigate its therapeutic potential.”
During the phase 1/2 study, those dosed with tofersen over a three-month period resulted in a statistically significant reduction of SOD1 protein levels in the cerebrospinal fluid and a numerical trend towards slowing of clinical decline as measured by the ALS Functional Rating Scale-Revised (ALSFRS-R).
More specifically, the mean change in ALSFRS-R score from baseline to Day 85 was -1.1 in the tofersen group, compared to -5.3 in the placebo arm.
“The interim results of this study, which achieved proof-of-biology and proof-of-concept, support the initiation of a phase 3 clinical trial to confirm the efficacy and safety of tofersen in SOD1-ALS patients and further demonstrate the potential of ASOs to target the genetic driver of disease,” said Michael Ehlers, executive vice president, research and development at Biogen.
“We are committed to bringing a potential breakthrough therapy to patients with ALS and we are expediting our efforts with the aim of addressing this urgent unmet need.”
Tofersen is just one of seven candidates licensed by Biogen from Ionis back in 2013. Biogen is on the look out for strong candidates to boost its prospects, especially after recently conceding defeat on one of its biggest pipeline hopes aducanumab in Alzheimer’s disease.
Michael Ehlers recently said the company won’t give up on Alzheimer’s just yet, confirming it will place focus on Ionis partnered, tau-targetting drugs BIIB092, BIIB076 and BIIB080 instead.