Nirsevimab EMA regulatory submission accepted under accelerated assessment for RSV protection in all infants

AstraZeneca’s Marketing Authorisation Application (MAA) for nirsevimab has been accepted under an accelerated assessment procedure by the European Medicines Agency (EMA), for the prevention of medically attended lower respiratory tract infections (LRTI) in all infants through their first respiratory syncytial virus (RSV) season. Nirsevimab is being developed by AstraZeneca in collaboration with Sanofi.

Nirsevimab is the first investigational long-acting antibody designed to provide RSV protection for all infants. It is being developed as a single dose for infants experiencing their first RSV season and for children at higher risk in their second RSV season. The MAA is based on positive results from the MELODY Phase III trial, MEDLEY Phase II/III trial, and Phase IIb trial which demonstrated nirsevimab’s safety and efficacy in providing protection against the virus for all infants with a single dose for the RSV season.

The EMA’s Committee for Medicinal Products for Human Use (CHMP) granted nirsevimab accelerated assessment as it was deemed of major interest for public health and therapeutic innovation. Accelerated assessment aims to reduce the timeframe for the CHMP to review a MAA compared to the standard procedure and follows the EMA granting access to the PRIority MEdicines (PRIME) scheme in 2019.

Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, AstraZeneca said: “Each year, respiratory syncytial virus causes seasonal epidemics of lower respiratory tract infections in infants and preventative options are currently limited to infants at higher-risk . We are excited that the EMA has accepted this regulatory submission under an accelerated assessment procedure, as nirsevimab has the potential to be the first immunisation to offer protection for all infants against respiratory syncytial virus as shown by the extensive clinical trial programme.”

Jean-François Toussaint, Global Head of Research and Development, Sanofi, said: “Respiratory syncytial virus is a leading cause of hospitalisation in all infants, and recent spikes in bronchiolitis and hospitalisations caused by respiratory syncytial virus infection around the globe further demonstrate the need for a preventative option that can help protect all infants. We are pleased to receive this regulatory filing acceptance and remain confident in nirsevimab’s potential to change the current RSV prevention paradigm as a possible single dose option that may offer sustained protection to all infants for the season”

Data from the MELODY and MEDLEY trials will be published in an upcoming peer-reviewed journal.

Additional regulatory submissions are planned to take place in 2022.


RSV is a common, contagious virus that causes seasonal epidemics of lower respiratory tract infections (LRTI), and is the leading cause of lower respiratory tract infection, such as bronchiolitis and pneumonia, in infants.1-3 It is also a leading cause of hospitalisations in all infants.3 Globally, in 2015, there were approximately 30 million cases of acute lower respiratory infections leading to more than three million hospitalisations, and it was estimated that there were 60,000 in-hospital deaths of children younger than five years.3-4 In recent months, there has been a resurgence of RSV following the easing of COVID-19 public health measures.5-6 Most hospitalisations for RSV occur in otherwise healthy infants born at term.7-11 Medically attended LRTIs are associated with increased costs to the healthcare system.12

Nirsevimab is an investigational long-acting antibody, being developed by AstraZeneca and Sanofi using AstraZeneca’s proprietary YTE technology, designed to protect all infants through their first RSV season. Due to its extended half-life technology, nirsevimab is being developed as a single dose for all infants experiencing their first RSV season and infants specific conditions, such as congenital heart disease or chronic lung disease, entering their first and second RSV season.13-15 The current anti-RSV antibody, AstraZeneca’s Synagis, is limited to high-risk infants and due to the shorter half-life requires up to five injections to cover a typical RSV season.16

Nirsevimab is an immunisation designed to provide direct prophylactic RSV protection to all infants via an antibody to help prevent LRTI caused by RSV. Monoclonal antibodies do not require the activation of the immune system to help offer rapid and direct protection against disease.17

Nirsevimab has been granted regulatory designations to facilitate expedited development by several regulatory agencies around the world. These include Breakthrough Therapy Designation by The China Center for Drug Evaluation under the National Medical Products Administration; Breakthrough Therapy Designation from the US Food and Drug Administration; access granted to the European Medicines Agency PRIority MEdicines (PRIME) scheme; and named “a medicine for prioritized development” under the Project for Drug Selection to Promote New Drug Development in Pediatrics by the Japan Agency for Medical Research and Development (AMED). Nirsevimab is currently under clinical investigation and has not been approved by any regulatory authority.

In March 2017, AstraZeneca and Sanofi announced an agreement to develop and commercialise nirsevimab. Under the terms of the agreement, AstraZeneca leads all development and manufacturing activities and Sanofi will lead commercialisation activities and record revenues. Under the terms of the global agreement, Sanofi made an upfront payment of €120m, has paid a development milestone of €30m and will pay up to a further €465m upon achievement of certain development and sales-related milestones. The two companies share all costs and profits. Revenue from the agreement is reported as Collaboration Revenue in the Company’s financial statements.

Related, in November 2018, AstraZeneca divested US commercial rights for Synagis to Swedish Orphan Biovitrum AB (publ) (Sobi) in addition to the right to participate in payments that may be received by AstraZeneca from the US profits or losses for nirsevimab. Under the agreement AstraZeneca received upfront consideration of $1.5bn, consisting of $1.0bn in cash and $500m in ordinary shares of Sobi upon completion, and received a total of $60m in non-contingent payments for nirsevimab during 2019-2021. AstraZeneca will also receive up to $470m in sales-related payments for Synagis, a $175m milestone following the submission of the Biologics License Application (BLA) for nirsevimab and potential net payments of approximately $110m on achievement of other nirsevimab profit and development-related milestones. Upon payment of the $175m milestone on BLA submission, Sobi’s ongoing participation will amount to AstraZeneca’s share of profits or losses under the aforementioned agreement with Sanofi for nirsevimab in the US. AstraZeneca will continue to manufacture and supply nirsevimab globally and is entitled to an additional royalty from Sobi if profits from nirsevimab in the US exceed a pre-specified level.

AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Diseases, and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology. Based in Cambridge, UK, AstraZeneca operates in over 100 countries and its innovative medicines are used by millions of patients worldwide. Please visit and follow the Company on Twitter @AstraZeneca.

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