EFFICACY AND SAFETY OF CLESROVIMAB, AN INVESTIGATIONAL RSV ANTIBODY, IN HEALTHY PRETERM AND FULL-TERM INFANTS: SUBGROUP ANALYSES OF A PHASE 2B/3 TRIAL (CLEVER) (ID 664)
MSD UK
Abstract
Background
In the phase 2b/3 trial, CLEVER (MK-1654-004; NCT04767373), clesrovimab, an investigational, long-acting monoclonal antibody, reduced the incidence of respiratory syncytial virus (RSV)– associated medically attended lower respiratory tract infection (MALRI) and RSV-associated hospitalization in infants, compared with placebo. We report results from the subgroup analyses of CLEVER.
Methods
Infants were randomized 2:1 to receive 1 dose of clesrovimab (105 mg) or placebo. Subgroup analyses were performed by gestational age (early and moderate preterm [≥29 to <35 weeks] or late preterm and full-term [≥35 weeks]), chronological age at randomization (<6 months or ≥6 months), and body weight at randomization (<5 kg or ≥5 kg).
Results
Overall, 2412 participants received clesrovimab and 1202 received placebo. The observed clesrovimab efficacies for RSV-associated MALRI requiring ≥1 or ≥2 indicators of LRI/severity; hospitalization; severe MALRI; LRI hospitalization; and acute respiratory tract infection were generally comparable across the subgroups analyzed, with overlapping 95% CIs in all instances (Figure 1), and consistent with those in the overall population. The observed clesrovimab efficacy tended to increase with increasing endpoint severity; this was also observed within the subgroups analyzed. The point estimate of clesrovimab efficacy relative to placebo for RSV-associated MALRI requiring ≥1 indicator of LRI/severity was higher in early/moderate preterm infants (9/417 vs 21/208), in participants aged <6 months (47/1915 vs 66/963), and in participants weighing <5 kg (23/860 vs 36/428), compared with their counterparts in the same subgroup categories (Figure 1). Within each subgroup analyzed, safety results (including injection site reactions, systemic, intervention-related, and serious adverse events) were generally comparable between intervention groups.
Conclusion
The results of this analysis support the efficacy of clesrovimab in healthy infants, independent of weight or gestational or chronological age.
Funding: This study was funded by Merck & Co., Inc., Rahway, NJ, USA.
Conflicts of interest: Authors are employees of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA, and may hold stock or stock options in Merck & Co., Inc., Rahway, NJ, USA.
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