Qalsody (tofersen) by Biogen: status and timeline

Qalsody (tofersen)

Slow or stop ALS caused by SOD1 mutations by switching off the toxic gene in the brain and spinal cord, and ultimately prevent the disease by treating carriers before symptoms start.

DeployStage 4 of 5

Approved in the US (2023) and EU (2024); ATLAS trial in presymptomatic SOD1 carriers ongoing.

Updated May 2024Checked 11 Oct0 updates this week

Milestones

Next · ATLAS: treat presymptomatic SOD1 carriers when neurofilament rises

VALOR phase 3: neurofilament down 55%, function missed significanceDoneComplete.
FDA accelerated approval for SOD1-ALS25 Apr 2023Complete.
EU approval under exceptional circumstancesMay 2024Complete.
ATLAS: treat presymptomatic SOD1 carriers when neurofilament risesNowCurrent milestone.

Most important updates

Current obstacles

Clinical benefit still being confirmedVALOR's 28-week function score missed significance; approval rests on neurofilament until ATLAS confirms benefit.
Repeated spinal injectionsLifelong lumbar punctures every 4 weeks are a burden and carry side effects like headache and back pain.

Physics limits

Dead motor neurons don't come backSilencing the gene can stop further damage but cannot regrow lost neurons, so benefit depends on treating early, ideally before symptoms.
One gene, few patientsEach antisense drug fixes one gene; SOD1 explains only about 2% of ALS, and most cases have no single known genetic cause to target.

How it works

4 parts

Antisense

A strand that matches SOD1's message

A short, chemically armoured DNA-like strand pairs with SOD1 messenger RNA and marks it for destruction.

Delivery

Injected into spinal fluid

Given by lumbar puncture so it bathes the spinal cord and brain, which a drug in the blood can't reach.

Effect

Less toxic protein

Mutant SOD1 misfolds and poisons motor neurons; lowering it slows nerve damage, seen as falling neurofilament.

Prevention

Treat before symptoms

Carriers' neurofilament rises months before weakness; ATLAS starts treatment at that signal.

Spec sheet

Spec	Qalsody (tofersen)
Plasma neurofilament change (28 wk)	-55% vs +12% on placebo^R (reported)
Spinal-fluid SOD1 protein	-35% vs -2% on placebo^R (reported)
SOD1-ALS patients in the US	~330 (about 2% of ALS)^R (reported)
Dosing	3 loading doses 14 days apart, then every 28 days^R (reported)
VALOR trial size	108 patients^R (reported)

^R reported by the company

Update log

2 updates

May 2024

Minor: EU approves Qalsody for SOD1-ALS under exceptional circumstancesPressRegulatory

Tue 25 Apr 2023

Major: FDA grants accelerated approval to Qalsody, the first treatment targeting a genetic cause of ALSFilingRegulatory

About Biogen

The team behind Qalsody (tofersen)

Biogen

Neurology drugs, Qalsody, antisense for ALS

US neuroscience drugmaker. It licensed tofersen from Ionis and sells it as Qalsody, the first drug that targets a genetic cause of ALS.

Qalsody: FDA accelerated approval April 2023, EU approval May 2024, for ALS caused by SOD1 mutations.
ATLAS phase 3 tests whether starting tofersen before symptoms can delay or prevent ALS.

biogen.com (opens biogen.com)Company profile →

Headquarters: United States
Status: Public
Valuation: public
Works in: BiotechRNAi & antisense drugs
Coverage: 1 program · 2 updateslatest 1 May 2024checked 11 Oct
Partners: Ionis Pharmaceuticals

Spec

Qalsody (tofersen)

Plasma neurofilament change (28 wk)

-55% vs +12% on placebo^R (reported)

Spinal-fluid SOD1 protein

-35% vs -2% on placebo^R (reported)

SOD1-ALS patients in the US

~330 (about 2% of ALS)^R (reported)

Dosing

3 loading doses 14 days apart, then every 28 days^R (reported)

VALOR trial size

108 patients^R (reported)