Santhera’s SYROS Study Shows Long-term Efficacy with Idebenone in Slowing Respiratory Function Loss in Patients with Duchenne Muscular Dystrophy

Pratteln, Switzerland, Santhera Pharmaceuticals (SIX: SANN) announces results
from the SYROS study demonstrating that long-term treatment with idebenone consistently reduced
the rate of respiratory function loss in patients with Duchenne muscular dystrophy (DMD) for up to 6
years in a real-world setting. This long-term data further support the potential for idebenone to
modify the course of respiratory function decline and delay the time to clinically relevant milestones.
The SYROS study was a prospectively planned collection of long-term, retrospective real-world data from
patients who completed the positive Phase III DELOS trial (18 out of 64) and were subsequently treated
with idebenone (900 mg/day) for on average 4.2 years (range 2.4-6.1 years) under Expanded Access
Programs (EAPs). The primary objective of this study was to evaluate the long-term evolution of the
respiratory function in patients who maintained treatment with idebenone for up to 6 years compared
to their preceding off-idebenone period.
The result of this study, which is consistent with outcomes from the pivotal DELOS study, demonstrated
 Switching to and maintaining long-term treatment with idebenone reduced the annual rate of
decline in forced vital capacity percent of predicted (FVC%p) by 50%.
 The treatment effect was consistently maintained year-on-year for up to 6 years.
 These findings are further supported by consistent reductions in the rate of both inspiratory and
expiratory respiratory function loss over the same period.
 Prolonged treatment with idebenone also reduced the risk of important patient-relevant outcomes,
including bronchopulmonary adverse events and hospitalizations due to respiratory causes.
“We are very excited to see that the significant treatment effect with idebenone observed in our 52-
week Phase III DELOS study is maintained over the long-term,” said Kristina Sjöblom Nygren, MD, Chief
Medical Officer and Head of Development at Santhera. “The new findings are highly relevant for DMD
patients in respiratory decline who have an urgent need for a therapy to modify the declining course of
respiratory function decline and ultimately delay the need for assisted ventilation.”
The findings from the SYROS study have been accepted for presentation at the 2019 MDA Clinical &
Scientific Conference (April 13-17, 2019, in Orlando) and will be submitted for publication in a peerreviewed journal.
Santhera’s SYROS Study Shows Long-term Efficacy with Idebenone in Slowing
Respiratory Function Loss in Patients with Duchenne Muscular Dystrophy
February 25, 2019 / Page 2 of 3
About Duchenne Muscular Dystrophy
DMD is one of the most common and devastating types of progressive muscle weakness and
degeneration starting at an early age and leading to early morbidity and mortality due to respiratory
failure. It is a genetic, degenerative disease that occurs almost exclusively in males with an incidence of
up to 1 in 3,500 live male births worldwide. DMD is characterized by a loss of the protein dystrophin,
leading to cell damage, impaired calcium homeostasis, elevated oxidative stress and reduced energy
production in muscle cells. With age, progressive respiratory muscle weakness affecting thoracic
accessory muscles and the diaphragm causes respiratory disease, impaired clearance of airway
secretions, recurrent pulmonary infections due to ineffective cough, and eventually respiratory failure.
There is currently no treatment approved for slowing loss of respiratory function in patients with DMD.
About Idebenone in Duchenne Muscular Dystrophy
Idebenone is a synthetic short-chain benzoquinone and a cofactor for the enzyme NAD(P)H:quinone
oxidoreductase (NQO1) capable of stimulating mitochondrial electron transport, reducing and
scavenging reactive oxygen species (ROS) and supplementing cellular energy levels.
DELOS was a Phase III, double-blind, placebo-controlled 52-week study which randomized 64 patients,
not taking concomitant steroids, to receive either idebenone (900 mg/day) or matching placebo. The
study met its primary endpoint, the change from baseline in Peak Expiratory Flow (PEF) expressed as
percent of predicted, which demonstrated that idebenone can slow the loss of respiratory function.
Additional respiratory function and clinical outcomes supported the results of the primary endpoint [1-5].
SYROS was a prospectively planned collection of long-term, retrospective real-world respiratory function
data from 18 patients who completed the DELOS study and subsequently received idebenone (900
mg/day) under Expanded Access Programs (EAPs). These long-term data showed that the previously
observed beneficial effect of idebenone in reducing the rate of respiratory function decline was
maintained over a >4 year average treatment period.
1. Buyse et al., 2015; Lancet 385:1748-57
2. McDonald et al., 2016; Neuromuscular Disorders 26: 473–480
3. Mayer et al. 2017; J Neuromuscular Diseases. 4:189-98
4. Buyse et al., 2017; Pediatric Pulmonology 52:508-515
5. Buyse et al. 2018; J Neuromuscular Diseases 5: 419–430
About Santhera
Santhera Pharmaceuticals (SIX: SANN) is a Swiss specialty pharmaceutical company focused on the
development and commercialization of innovative medicines for rare and other diseases with high unmet
medical needs. The portfolio comprises clinical stage and marketed treatments for neuroophthalmologic, neuromuscular and pulmonary diseases. Santhera’s Raxone® (idebenone) is authorized
in the European Union, Norway, Iceland, Liechtenstein, Israel and Serbia for the treatment of Leber’s
hereditary optic neuropathy (LHON) and is currently commercialized in more than 20 countries. For
further information, please visit
is a trademark of Santhera Pharmaceuticals.
Santhera’s SYROS Study Shows Long-term Efficacy with Idebenone in Slowing
Respiratory Function Loss in Patients with Duchenne Muscular Dystrophy
February 25, 2019 / Page 3 of 3
For further information please contact: or
Eva Kalias, Head External Communications
Phone: +41 79 875 27 80
For Investors: or
Christoph Rentsch, Chief Financial Officer Hans Vitzthum, LifeSci Advisors
Europe: +41 61 906 89 65 US: +1 212 915 2568
Disclaimer / Forward-looking statements
This communication does not constitute an offer or invitation to subscribe for or purchase any securities
of Santhera Pharmaceuticals Holding AG. This publication may contain certain forward-looking
statements concerning the Company and its business. Such statements involve certain risks,
uncertainties and other factors which could cause the actual results, financial condition, performance or
achievements of the Company to be materially different from those expressed or implied by such
statements. Readers should therefore not place undue reliance on these statements, particularly not in
connection with any contract or investment decision. The Company disclaims any obligation to update
these forward-looking statements.
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Shiwani Sharma

Shiwani Sharma was Senior Editor at PharmaShots. She has in-depth knowledge of the life sciences industry including the Pharma and Biotech sectors. Any articles written by her can be contacted at

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