Merck & Co (MSD) has received the European Commission (EC) approval for Enflonsia (clesrovimab), indicated to prevent respiratory syncytial virus (RSV) lower respiratory tract disease in newborns and infants during their initial RSV season.
This approval authorises Enflonsia’s marketing across all 27 European Union member states, Iceland, Liechtenstein and Norway.
Enflonsia is a long-acting monoclonal antibody intended for prevention, providing protection over five months, aligning with a typical RSV season, using non-weight-based dosing.
It is contraindicated for infants with hypersensitivity to its active substance or excipients.
The availability in each country will depend on national reimbursement procedures.
Merck Research Laboratories' global clinical development therapeutic area head and vice-president Dr Macaya Douoguih said: “The European Commission approval of Enflonsia marks a significant milestone in our journey to enable broad access and help reduce the burden of RSV disease on infants around the world.
“We are proud to bring Enflonsia to infants in Europe and look forward to equipping families and health care providers with this important new preventive option to help address this widespread and potentially serious disease."
The EC’s decision is based on the pivotal Phase IIb/III CLEVER trial (MK-1654-004), which assessed the safety and efficacy of a single Enflonsia dose in preterm and full-term infants, and on interim data from the Phase III SMART trial (MK-1654-007), comparing Enflonsia to palivizumab in high-risk infants.
CLEVER trial results indicated that the antibody reduced the incidence of RSV-associated medically attended lower respiratory infections by 60.4% and hospitalisations by 84.2% through five months compared to a placebo.
Further reductions were observed in severe cases and hospitalisations, with a safety profile comparable to a placebo.
The SMART trial demonstrated comparable incidence rates of RSV-associated lower respiratory infections and hospitalisations between Enflonsia and palivizumab with similar safety profiles.
Earlier this month, MSD and Daiichi Sankyo received priority review from the US Food and Drug Administration (FDA) for ifinatamab deruxtecan’s biologics licence application (BLA) to treat extensive-stage small cell lung cancer (ES-SCLC).
