Nirsevimab
- Generic Name
- Nirsevimab
- Brand Names
- Beyfortus
- Drug Type
- Biotech
- CAS Number
- 1989556-22-0
- Unique Ingredient Identifier
- VRN8S9CW5V
- Background
Nirsevimab (MEDI8897) is a recombinant human immunoglobulin G1 kappa (IgG1ĸ) monoclonal antibody used to prevent respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants. It binds to the prefusion conformation of the RSV F protein, a glycoprotein involved in the membrane fusion step of the viral entry process, and neutralizes several RSV A and B strains. Compared to palivizumab, another anti-RSV antibody, nirsevimab shows greater potency at reducing pulmonary viral loads in animal models. In addition, nirsevimab was developed as a single-dose treatment for all infants experiencing their first RSV season, whereas palivizumab requires five monthly doses to cover an RSV season. This is due to a modification in the Fc region of nirsevimab that grants it a longer half-time compared to typical monoclonal antibodies.
On November 2022, nirsevimab was approved by the EMA for the prevention of RSV lower respiratory tract disease in newborns and infants. Nirsevimab was also approved by Health Canada on April 19, 2023 and by the FDA in July 17, 2023 for the same indication.
- Indication
Nirsevimab is indicated for the prevention of respiratory syncytial virus (RSV) lower respiratory tract disease in neonates and infants during their first RSV season in Canada, the US, and Europe. Additionally, Nirsevimab is also approved in Canada and the US for use in infants up to 24 months of age who remain vulnerable to severe RSV disease through their second RSV season. These infants include, but are not limited to, those with chronic lung disease of prematurity, hemodynamically significant congenital heart disease, immunocompromised states, Down syndrome, cystic fibrosis, neuromuscular disease, and congenital airway anomalies.
- Associated Conditions
- Lower Respiratory Tract Disease caused by Respiratory Syncytial Virus (RSV)
NanoViricides' Broad-Spectrum Antiviral NV-387 Advances to Phase II Trials for MPox Treatment
• NanoViricides has received approval from the Democratic Republic of Congo's National Ethics Committee to proceed with Phase II clinical trials of NV-387 for MPox treatment, addressing a significant unmet need as no effective treatment currently exists.
• NV-387 employs a revolutionary host-mimetic mechanism that "looks like a cell" to viruses, potentially making it effective against 90-95% of human pathogenic viruses while being highly resistant to viral escape mutations.
• The drug has demonstrated superior efficacy in animal models against multiple viruses including influenza, RSV, coronavirus, and orthopoxviruses, outperforming existing treatments like Tamiflu, remdesivir, and matching tecovirimat against MPox-like infections.
Dr. Reddy's to Launch Sanofi's Beyfortus in India for RSV Prevention in Infants
• Dr. Reddy's Laboratories has secured exclusive rights to promote and distribute Sanofi's novel RSV drug Beyfortus (nirsevimab) in India, expanding their existing vaccine partnership.
• Beyfortus, a monoclonal antibody administered as a prefilled injection, prevents respiratory syncytial virus (RSV) lower respiratory tract disease in newborns and infants during their first RSV season.
• The drug, already approved in major markets including the EU, US, and China, received marketing authorization from India's CDSCO in June and is expected to launch in the second quarter of the current fiscal year.
Ziresovir Shows Breakthrough Efficacy Against RSV in Infants Under 6 Months with Long-Term Benefits
• Phase III trial results published in The Lancet Child & Adolescent Health demonstrate ziresovir is the first RSV-targeted antiviral to show significant clinical efficacy in hospitalized infants under 6 months of age.
• Treatment with ziresovir led to a 54.5% greater reduction in bronchiolitis symptoms and significantly faster viral clearance compared to placebo, with improvements in respiratory rate, wheezing, and chest retractions.
• Two-year follow-up data revealed long-term respiratory benefits, including 3.6 times lower incidence of recurrent wheezing and reduced asthma rates, suggesting early antiviral intervention may prevent chronic respiratory conditions.
Sanofi Acquires Dren Bio's Novel B-Cell Depleter for $600 Million, Expanding Immunology Pipeline
• Sanofi has agreed to acquire Dren Bio's DR-0201, a first-in-class bispecific myeloid cell engager that induces deep B-cell depletion, for an upfront payment of $600 million.
• DR-0201 works by targeting CD20 and engaging tissue-resident myeloid cells, potentially resetting the immune system in patients with refractory B-cell mediated autoimmune diseases like lupus.
• The acquisition strengthens Sanofi's immunology portfolio and includes potential future payments of $1.3 billion upon achievement of development and launch milestones, with transaction expected to close in Q2 2025.
RSV Treatment Landscape Expands with New Vaccines and Clinical Trials in 2024-2025
• Moderna's mRESVIA vaccine received MHRA approval in February 2025 for adults aged 60 and older, joining GSK's Arexvy and Pfizer's Abrysvo in the expanding RSV vaccine market.
• The FDA has mandated new safety warnings for RSV vaccines regarding Guillain-Barré Syndrome risk, highlighting ongoing safety monitoring efforts in early 2025.
• Multiple pharmaceutical companies including Sanofi, GSK, and Pfizer are conducting advanced clinical trials in 2024, focusing on various patient populations and novel therapeutic approaches.
Personalized mRNA Vaccines Show Promise in Early-Phase Pancreatic Cancer Trial
• A Phase 1 clinical trial published in Nature demonstrates encouraging results for personalized mRNA vaccines in treating pancreatic cancer, offering hope for one of the deadliest cancer types.
• The development addresses a critical medical need, as pancreatic cancer has a devastating five-year survival rate of less than 13% and is typically diagnosed at advanced stages in 90% of cases.
• The trial represents a significant advancement in applying mRNA technology beyond infectious diseases, potentially opening new avenues for personalized cancer immunotherapy.
EU Approves Beyfortus: First Single-Dose RSV Prevention for Infants
• AstraZeneca and Sanofi's Beyfortus (nirsevimab) receives European Commission approval as the first single-dose antibody treatment for RSV prevention in both full-term and pre-term infants.
• Clinical trials demonstrated Beyfortus reduced medically attended RSV-related lower respiratory tract infections by 74.5% compared to placebo, offering superior convenience over monthly-dosed alternatives.
• The approval addresses a significant global health burden, as RSV causes over 3 million hospitalizations and nearly 60,000 deaths annually in children under five.
Shionogi's Oral Antiviral S-337395 Shows Promise in Phase 2 RSV Human Challenge Trial
• Shionogi's investigational oral antiviral S-337395 significantly reduced viral load in a Phase 2 human challenge trial for Respiratory Syncytial Virus (RSV).
• The highest dose group of S-337395 demonstrated an 88.94% reduction in viral load compared to the placebo group (P<0.0001), along with improved clinical symptom scores.
• S-337395 was generally safe and well-tolerated, with no serious adverse events reported during the randomized, double-blind, placebo-controlled study.
• The drug, which has received FDA Fast Track designation, inhibits the RSV L protein, essential for viral replication, offering a potential new treatment approach.
Sanofi and SK bioscience's 21-Valent Pneumococcal Vaccine Enters Phase III Trials
• Sanofi and SK bioscience have initiated global Phase III trials for their 21-valent pneumococcal conjugate vaccine candidate, GBP410, targeting individuals aged six weeks to 17 years.
• The Phase III program will enroll over 7,700 participants across multiple regions, assessing the vaccine's safety and immunogenicity with varying doses based on age.
• This collaboration expands on their existing partnership, with Sanofi paying SK bioscience €50M upfront and potential milestone payments for developing next-generation pneumococcal vaccines.
• GBP410 demonstrated comparable immunogenicity and safety to Prevnar 13 in Phase II trials, suggesting its potential to minimize invasive pneumococcal disease in young children.
Real-World Study Confirms High Effectiveness of RSV Vaccines in Older Adults
• A real-world study among older US veterans showed RSV vaccines are highly effective against infection, ED/UC visits, and hospitalization.
• The study found vaccine effectiveness of 78% against RSV infection, 79% against ED/UC visits, and 80% against hospital admissions.
• Vaccine effectiveness against RSV infection was 72.3% in veterans aged 80 years and older and 71.6% in those with weakened immune systems.
• The findings support current recommendations for RSV vaccination in adults aged 60 years and older, with updated CDC guidance for the 2024-2025 season.
FDA Accepts Merck's Clesrovimab BLA for RSV Prevention in Infants
• The FDA has accepted Merck's Biologics License Application (BLA) for clesrovimab, a long-acting monoclonal antibody, with a decision expected by June 10, 2025.
• Clesrovimab aims to protect infants from respiratory syncytial virus (RSV) disease during their first RSV season with a single-dose administration.
• Clinical trial data from the CLEVER and SMART studies support the BLA, demonstrating a significant reduction in RSV-associated infections and hospitalizations.
• If approved, Merck anticipates clesrovimab will be available for order by July 2025, targeting the 2025-2026 RSV season, offering a potential competitive edge.
FDA Panel Urges Caution and More Data on RSV Vaccine Safety in Infants
• An FDA advisory panel called for more safety data on RSV vaccines for infants, highlighting concerns after a partial pause in clinical trials.
• The pause was triggered by cases of severe RSV in infants receiving Moderna's experimental vaccines, raising questions about vaccine-associated enhanced respiratory disease (VAERD).
• The panel emphasized the need for a better understanding of immune responses in different age groups and continued monitoring of trial participants.
• Despite concerns, advisors spoke positively about Sanofi's Beyfortus and Pfizer's maternal RSV vaccine, and did not call for halting all infant RSV vaccine studies.
Sanofi Korea to Launch Beyfortus for RSV Prevention in Infants
• Sanofi Korea will launch Beyfortus (nirsevimab) early next year to prevent RSV in infants, following its approval by the Ministry of Food and Drug Safety.
• Clinical data from the MELODY phase 3 trial showed a 74.5% reduction in RSV-related lower respiratory tract infections requiring medical attention.
• Real-world evidence from Galicia, Spain, indicated an 82% reduction in RSV-related hospitalizations among infants under six months after Beyfortus was introduced.
• A CDC study in the U.S. found Beyfortus to be 90% effective in preventing RSV-related hospitalizations among infants during the 2023-2024 RSV season.
Nirsevimab Shows High Efficacy in Preventing RSV Hospitalizations in Infants
• A new study reveals that nirsevimab, a monoclonal antibody injection, is highly effective in preventing RSV-related hospitalizations in infants, with a 93% reduction reported.
• Real-world data from Ireland demonstrates a 94% decrease in RSV hospitalizations among babies under one year old following the rollout of nirsevimab.
• The CDC reports that nirsevimab reduced RSV-related hospitalizations by 89% in Alaska's Yukon-Kuskokwim Delta during the first season of its administration.
• Unlike vaccines, nirsevimab provides immediate protection by directly dosing infants with antibodies, offering a crucial preventative measure against severe RSV infections.
RSV Vaccines and Monoclonal Antibodies: A Year in Review
• FDA approved Moderna's mRNA-1345 (mResvia) for adults 60+ and expanded approvals for GSK's Arexvy and Pfizer's Abrysvo to include younger at-risk adults.
• ACIP updated RSV vaccination recommendations, advising a single dose for adults 75+ and considering it for those 60-74 at increased risk.
• Studies confirmed the safety of Pfizer's maternal RSV vaccine regarding preterm birth and demonstrated nirsevimab's effectiveness in preventing RSV hospitalizations in infants.
• Clesrovimab, an investigational monoclonal antibody, showed promise in reducing RSV-related lower respiratory infections and hospitalizations in infants.
RSV Prevention: Maternal Vaccine and Monoclonal Antibody Show Promise in Protecting Infants
• Maternal RSV vaccines, administered between 32 and 36 weeks of gestation, protect infants through placental antibody transfer, lasting 4-6 months.
• Nirsevimab, a monoclonal antibody given at birth, also provides 4-6 months of protection against severe RSV disease, with effectiveness around 70% against hospitalization.
• Both interventions have demonstrated high efficacy (60-70%) in clinical trials, significantly reducing infant hospitalizations due to RSV infection.
• Logistical challenges, including narrow gestational window for vaccine and reimbursement issues for nirsevimab, impact uptake and accessibility.
MSD's Clesrovimab Shows Promise in RSV Prevention, Eyes 2025 Launch
• MSD's clesrovimab demonstrated a 60% reduction in RSV-associated medically attended lower respiratory infections (MALRI) in infants in a Phase IIb/III trial.
• The monoclonal antibody also reduced RSV-associated hospitalizations by 84.2% and LRTD hospitalizations by 90.9% over five months compared to placebo.
• Interim Phase III data showed clesrovimab has a comparable safety profile to Synagis, with similar incidence rates of RSV-associated MALRI and hospitalizations.
• MSD is in discussions with health authorities, aiming for a potential launch of clesrovimab in time for the 2025-2026 RSV season.
Clesrovimab Shows Promise in Preventing RSV Infections in Infants
• Clesrovimab significantly reduced RSV-associated medically attended lower respiratory infection (MALRI) by 60.4% compared to placebo in infants.
• The monoclonal antibody reduced RSV-associated hospitalizations by 84.2% and lowered RSV-associated LRI hospitalizations by 90.9% through five months.
• Interim data from a Phase 3 trial indicate that clesrovimab has a comparable safety profile to palivizumab in high-risk infants.
• Merck anticipates clesrovimab could potentially be available for infants as early as the 2025-2026 RSV season, pending regulatory approvals.
Opdivo Approved for Perioperative Lung Cancer Treatment; Pharma Companies Announce Layoffs and Investments
• Bristol Myers Squibb's Opdivo receives FDA approval for perioperative treatment of non-small cell lung cancer, reducing relapse risk by 42%.
• Johnson & Johnson will invest $2 billion in a new biologics manufacturing facility in North Carolina, creating 420 jobs.
• Several pharmaceutical companies, including Johnson & Johnson, Bayer, and Pfizer, announce layoffs in New Jersey and Ireland.
• WHO recommends RSV vaccination for pregnant women and antibody treatment for infants; Pfizer's Abrysvo and Sanofi/AstraZeneca's Beyfortus are key players.
FDA Approves New Manufacturing Line for Sanofi and AstraZeneca's Beyfortus, Boosting RSV Protection for Infants
• The FDA has approved a new manufacturing line for Sanofi and AstraZeneca's Beyfortus, an RSV antibody, to increase U.S. supply for the upcoming season.
• Beyfortus is a long-acting monoclonal antibody that provides passive immunity against RSV in newborns and infants by blocking viral entry into host cells.
• Clinical data shows Beyfortus has high real-world effectiveness, consistently exceeding 80% in preventing RSV disease and hospitalizations in infants.
• Sanofi has begun shipping Beyfortus doses to healthcare providers and the CDC, ensuring wider availability for both in-season and off-season immunization.
Drug Development Updates
Stay informed with timely notifications on clinical trials, regulatory changes, and research advancements related to this medication.
© Copyright 2025. All Rights Reserved by MedPath