* New data from the RESPOND study show that neurofilament levels, an indicator

    of neurodegeneration, were reduced in nearly all study participants treated
    with SPINRAZA
  * Reductions in biomarker complement previously reported RESPOND efficacy
    results showing improved motor function in most participants treated with
    SPINRAZA after gene therapy

CAMBRIDGE, Mass., March 06, 2024 (GLOBE NEWSWIRE) -- Biogen Inc.
(http://www.biogen.com) (Nasdaq: BIIB) announced interim 6-month biomarker data
from the initial 29 participants in the open-label RESPOND study.(*) The Phase
4 study evaluates clinical outcomes and safety following treatment with SPINRAZA
over a 2-year period in infants and toddlers with spinal muscular atrophy (SMA)
who have unmet clinical needs after treatment with Zolgensma(®) (onasemnogene
abeparvovec). The new data show that plasma neurofilament light chain (NfL)
levels, an objective biomarker of axonal injury and neurodegeneration, were
reduced in nearly all study participants treated with SPINRAZA. These data will
be presented at the 2024 Muscular Dystrophy Association (MDA) Clinical &
Scientific Conference (March 3-6, 2024).
"Our evolving understanding of gene therapy indicates there may be an
opportunity for better outcomes," said Crystal Proud, M.D., Pediatric
Neurologist at Children's Hospital of the King's Daughters. "Improvements in
motor function together with decreases in neurofilament levels seen after
treatment with SPINRAZA in RESPOND show that we may be able to further maximize
benefits for patients."
Today NfL data are being presented from study participants treated with SPINRAZA
for 6 months showing:
Among participants with 2 SMN2 copies:

  * All participants had elevated baseline NfL levels relative to healthy
    children of similar age
  * In infants (n=11) who were 9 months or younger at first SPINRAZA dose (mean
    baseline NfL: 148.3 pg/mL), NfL levels decreased by a mean of 70% from
    baseline.
  * In children (n=11) over 9 months of age at first SPINRAZA dose (mean
    baseline NfL: 121.8 pg/mL), NfL levels decreased by a mean of 78% from
    baseline.

Among participants with 3 SMN2 copies:

  * Baseline NfL levels were elevated in 2 of 3 children (mean: 60.6 pg/mL).
  * NfL reductions were observed in those with elevated levels at baseline and
    remained stable in the participant without an elevated level at baseline.

"Biogen is at the forefront of pioneering research aimed at advancing biomarkers
to accelerate development of drugs for people living with devastating
neurodegenerative diseases like SMA and ALS," said Priya Singhal, M.D., M.P.H.,
Head of Development and interim Chief Medical Officer at Biogen. "Prior to
receiving SPINRAZA at the start of RESPOND, we saw that participants had
elevated neurofilament levels, as compared to healthy children suggesting
ongoing neuronal injury. The RESPOND findings underscore the value of
neurofilament as an objective marker for assessing remaining unmet needs in SMA
patients who have previously received gene therapy."
As reported at the SMA Research & Clinical Care Meeting in June 2023 from the
same 29 participants, improvements in motor function were observed in most
participants as measured by increased mean total Hammersmith Infant Neurological
Examination Section 2 (HINE-2) score from baseline.(1) No new emerging safety
concerns have been identified in enrolled RESPOND participants who received
SPINRAZA after Zolgensma. After a median of 230.5 days in the study, serious
adverse events (AEs) were reported in 13/38 (34%) participants. Any AEs were
reported in 31/38 (81.6%) participants. No serious AEs were considered related
to SPINRAZA or led to study withdrawal, although some were related to
administration.
These data and additional data from the RESPOND study will be presented at
subsequent conferences this year including the 4th International Congress on
Spinal Muscular Atrophy hosted by SMA Europe.
About SPINRAZA® (nusinersen)
SPINRAZA is approved in more than 71 countries to treat infants, children and
adults with spinal muscular atrophy (SMA). As a foundation of care in SMA, more
than 14,000 individuals have been treated with SPINRAZA worldwide.(2)
SPINRAZA is an antisense oligonucleotide (ASO) that targets the root cause of
SMA by continuously increasing the amount of full-length survival motor neuron
(SMN) protein produced in the body.(3)?It is administered directly into the
central nervous system, where motor neurons reside, to deliver treatment where
the disease starts.(3)
SPINRAZA has demonstrated sustained efficacy across ages and SMA types with a
well-established safety profile based on data in patients treated up to 8
years,(3) combined with unsurpassed real-world experience. The nusinersen
clinical development program encompasses more than 10 clinical studies, which
have included more than 460 individuals across a broad spectrum of patient
populations,?including two randomized controlled studies (ENDEAR and CHERISH).
The SHINE and NURTURE open-label extension studies are evaluating the long-term
impact of SPINRAZA. The most common adverse events observed in clinical studies
were respiratory infection, fever, constipation, headache, vomiting and back
pain. Laboratory tests can monitor for renal toxicity and coagulation
abnormalities, including acute severe low platelet counts, which have been
observed after administration of some ASOs.
Biogen licensed the global rights to develop, manufacture and commercialize
SPINRAZA from Ionis Pharmaceuticals, Inc. (Nasdaq: IONS). Please click here
for?Important Safety Information
(https://www.globenewswire.com/Tracker?data=iXzfn_p14a-
__d5Ld9JxkoN2zTtSciqjgl8x733FYVDI-
8ag3CfYJABnxuWQi0afmywqvaxg0SbjHQelNZBa1WBbCrqfHICoc221KBqe4k-
TObzd2gjOOx8jgQdIeVRnwzM1vMhcEEfsWSBTOBU3-
xs2MdODZebstRTAMwb3NzznP2bytWV1Tstil12V0p-
ewDRtBa0X88LegQhJoDNEs7nKqWsBPYE_f0wK2R46xc3AAW6cPdi_A-
o5D9z9gVnjTHFCW_n52uNrf33TVeI9a8G1PxCGc818VOI0UnbDpDbzhg9POWj-qc06qWVOpRsHhbjWr-
vL0bL6OI3z_FETitEH9TwOB2lyEo0iumgEXAA=)?and?full Prescribing Information
(https://www.globenewswire.com/Tracker?data=160z_F9AVA-
qSWq7EM1gd8fEQuUq_9TJkFpakJW6VnRSGVTS2GTwSPv9oqBzuFBashqBhjf6i6j-Ih4HU-X-
Fk7i38OFEsDAeX3QylZp0bhhjqREXnhHx1EAuD4Ctcz4LX47PEr-
BfKNg2jbmF2rN96mgKGjNi9pRsVjddON8OcsZLxhaJf55j0Gua8o73IS6KZv5XsjkTrtaWBrSXKC4Tya
JOECaRApbxMcKGXJigWyysmmq0WfL9nQqsncw-
eV5gPu6F6woAJC74BTRTFbevlNhLkptiTgsJeSQ1FNpF59Rz8IGXSZ2zBGDEEWt3jZfJKw2x9OlQ042m
5aV1ZhdnT0ZpPnjlUeeW0VhwVK9z7RI3883FcrDAVpr6F4bL0a7Zo1yr5a7HZPbu5XguE-
VyT2Z_DAN1BP3EBdk2fExyBX9rxf8_Wu_g8lU_Api_tC)?for SPINRAZA in the U.S., or visit
your respective country's product website.
About Biogen
Founded in 1978, Biogen is a leading biotechnology company that pioneers
innovative science to deliver new medicines to transform patient's lives and to
create value for shareholders and our communities. We apply deep understanding
of human biology and leverage different modalities to advance first-in-class
treatments or therapies that deliver superior outcomes. Our approach is to take
bold risks, balanced with return on investment to deliver long-term growth.
We routinely post information that may be important to investors on our website
at www.biogen.com (https://www.biogen.com/). Follow us on social media -
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(https://www.linkedin.com/company/biogen-/), X (https://twitter.com/biogen),
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Biogen Safe Harbor
This news release contains forward-looking statements, the potential clinical
effects of SPINRAZA; the potential benefits, safety and efficacy of SPINRAZA;
the clinical development program for SPINRAZA; the identification and treatment
of SMA; our research and development program for the treatment of SMA; the
potential of our commercial business and pipeline programs, including SPINRAZA;
and risks and uncertainties associated with drug development and
commercialization. These forward-looking statements may be accompanied by words
such as "aim," "anticipate," "believe," "could," "estimate," "expect,"
"forecast," "intend," "may," "plan," "potential," "possible," "will," "would"
and other words and terms of similar meaning. Drug development and
commercialization involve a high degree of risk, and only a small number of
research and development programs result in commercialization of a product.
Results in early-stage clinical trials may not be indicative of full results or
results from later stage or larger scale clinical trials and do not ensure
regulatory approval. You should not place undue reliance on our forward-looking
statements.
These statements involve risks and uncertainties that could cause actual results
to differ materially from those reflected in such statements, including without
limitation, uncertainty of success in the development and potential
commercialization of SPINRAZA; the risk that we may not fully enroll our
clinical trials or enrollment will take longer than expected; unexpected
concerns may arise from additional data, analysis or results obtained during our
clinical trials; regulatory authorities may require additional information or
further studies, or may fail or refuse to approve or may delay approval of our
drug candidates, including SPINRAZA; the occurrence of adverse safety events;
the risks of unexpected hurdles, costs or delays; failure to protect and enforce
our data, intellectual property and other proprietary rights and uncertainties
relating to intellectual property claims and challenges; product liability
claims; results of operations and financial condition. The foregoing sets forth
many, but not all, of the factors that could cause actual results to differ from
our expectations in any forward-looking statement. Investors should consider
this cautionary statement, as well as the risk factors identified in our most
recent annual or quarterly report and in other reports we have filed with the
U.S. Securities and Exchange Commission. These statements speak only as of the
date of this news release.
We do not undertake any obligation to publicly update any forward-looking
statements.
References:
1. Proud C. Interim results from the ongoing RESPOND study evaluating

    nusinersen in children with spinal muscular atrophy previously treated with
    onasemnogene abeparvovec. June 2023. SMA Research & Clinical Care Meeting.
    Orlando, Fla.

2. Based on commercial patients, early access patients, and clinical trial
participants through December 31, 2022.?
3. SPINRAZA U.S. Prescribing Information. Available at:
https://www.spinraza.com/content/dam/commercial/specialty/spinraza/caregiver /en_us/pdf/spinraza-prescribing-information.pdf. Accessed: February 2024.
4. Core Data sheet, Version 13, October 2021. SPINRAZA. Biogen Inc, Cambridge,
MA.
* Clinical outcomes and NfL were analyzed in the 29 participants who had the
opportunity for at least six months of treatment at the time of the interim
analysis. Analysis of mean change in NfL includes participants with baseline and
Day 183 assessments; a mean change from baseline was not reported in the 3 SMN2
copies group, due to the small number of participants. Safety data are reported
in all participants (n=38) who received at least one dose of SPINRAZA in the
trial.

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 Biogen                                    Biogen
 Jack Cox                                  Chuck Triano
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 public.affairs@biogen.com                 IR@biogen.com (mailto:IR@biogen.com)

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