Treatment with two doses of depemokimab results in sufficient concentrations to adequately control blood eosinophil counts (BEC) over 1 year, as shown in the ANCHOR 1 and 2 trials. This finding suggests sustained anti-interleukin-5 (IL-5) biological effect and impact on type 2 inflammation.

“Depemokimab is the first ultra-long-acting biologic engineered with enhanced IL-5 binding affinity, high potency, and an extended half-life, enabling twice-yearly dosing,” said lead author Dr Martin Desrosiers from Universite de Montreal, Montreal, Canada, who presented the study at the AAAAI/WAO 2025.

ANCHOR 1 and 2 investigated the pharmacokinetic (PK) and pharmacodynamic (PD) durability of depemokimab in adults with inadequately controlled chronic rhinosinusitis with nasal polyps (CRSwNP), previous NP surgery, or treatment with/intolerance to systemic corticosteroids.

Desrosiers and his team randomized eligible patients in a 1:1 ratio to receive either depemokimab 100 mg subcutaneously (n=272) or placebo (n=256) every 26 weeks over 52 weeks. They summarized plasma concentrations (PK), log_e transformed BEC (PD), as well as analysed ratio to baseline.

A total of 272 patients were included in PK summaries. The mean depemokimab concentration at first assessment following administration (week 4) was 10.65 mg/mL, with the lowest concentrations noted at weeks 26 (predose; 1.02 mg/mL) and 52 (1.25 mg/mL). [AAAAI 2025, abstract L80]

Baseline geometric mean BEC were 344 (95 percent confidence interval [CI], 312?379) cells/mL for depemokimab and 322 (95 percent CI, 290?357) for placebo. At week 4, the BEC ratio to baseline was 0.104 (95 percent CI, 0.091?0.118; p<0.001) for the study drug versus placebo.

Desrosiers and colleagues observed sustained relative reductions throughout the first (week 26: 0.168, 95 percent CI, 0.148?0.191; p<0.001) and second dosing intervals (week 52: 0.153, 95 percent CI, 0.133_0.176; p<0.001). The results persisted across trials.

“These findings support depemokimab as a twice-yearly option for patients with CRSwNP,” Desrosiers said.

Safety, efficacy

Replicate ANCHOR 1 and 2 trials also demonstrated the safety and efficacy of depemokimab twice yearly in patients with CRSwNP.

Significant improvements in total endoscopic nasal polyp score (NPS) were observed in patients treated with depemokimab versus placebo at 1 year in both studies (ANCHOR 1: treatment difference [TD], ?0.7, 95 percent CI, ?1.1 to ?0.3; p<0.001; ANCHOR 2: TD, ?0.6, 95 percent CI, ?1.0 to ?0.2; p=0.004; integrated: TD, ?0.7, 95 percent CI, ?0.9 to ?0.4). [AAAAI 2025, abstract L46]

Depemokimab also resulted in significantly improved mean nasal obstruction verbal response scale over weeks 49?52 (ANCHOR 1: TD, ?0.23, 95 percent CI, ?0.46 to 0.00; p=0.047; ANCHOR 2: TD, ?0.25, 95 percent CI, ?0.46 to ?0.03; p=0.025; integrated: TD, ?0.24, 95 percent CI, ?0.39 to ?0.08).

The incidence of adverse events (AEs; ANCHOR 1: 74 percent vs 79 percent; ANCHOR 2: 76 percent vs 80 percent) and serious AEs (ANCHOR 1: 3 percent vs 5 percent; ANCHOR 2: 5 percent vs 8 percent) was comparable between patients treated with depemokimab and those who received placebo.

Both studies were funded by GSK.