MSD (MRK.US) long-acting RSV monoclonal antibody to be included in priority review in China

The Zhitong Finance App learned that on June 17, CDE's official website showed that MSD (MRK.US)'s Clesrovimab (MK-1654) injection marketing application is to be included in priority review. The indication is to prevent lower respiratory infections caused by RSV in newborns and infants about to enter or be born during the first respiratory syncytial virus (RSV) epidemic season.

It is known that RSV is a contagious virus that can cause widespread seasonal infections. Clesrovimab is a prophylactic long-acting monoclonal antibody that can induce passive immunity against RSV by binding to RSV's fusion glycoprotein to prevent RSV infection, and is designed to provide immediate, rapid, and long-lasting protection to infants. Clesrovimab was just approved for marketing by the US FDA on June 9. It is the first and only single-dose RSV monoclonal antibody for infants, regardless of the patient's body weight.

The CLEVER study is a randomized, double-blind, placebo-controlled phase IIb/III clinical trial evaluating the efficacy of administering a single dose of Clesrovimab to premature infants and full-term infants (birth to 1 year). The trial reached a primary endpoint and a critical secondary endpoint. Compared to placebo, the Clesrovimab group reduced the incidence of RSV-associated lower respiratory infections (MALRI) requiring medical attention by 60.5% (95% CI: 44.2, 72.0, p<0.001) and reduced RSV-related hospitalizations by 84.3% (95% CI: 66.7, 92.6, p<0.001) on day 150 (5 months) after administration.

The SMART study is a randomized, partially blinded, multicenter phase III clinical trial to evaluate the safety and efficacy of Clesrovimab head-to-head palibumab in infants at high risk of severe RSV infection. The SMART test results showed that the incidence of RSV-related MALRI of Clesrovimab and palizumab was comparable to the RSV-related hospitalization rate; the safety was also roughly comparable to that of palizumab, and was consistent with the safety of Clesrovimab in infants in the CLEVER trial.

Domestically, currently only AstraZeneca/Sanofi's nicevirumab has been approved. MSD's Clesrovimab has been listed. In addition, two RSV monoclonal antibodies have entered phase III clinical trials, from Tylomab (TNM001) and Ruiyang Biotech (RB0026).