Biopharmaceutical company GSK plc (LSE/NYSE: GSK) announced on Monday that it presented positive results from its ANCHOR-1 and ANCHOR-2 phase III trials at the 2025 AAAAI/WAO Joint Congress in San Diego, California.

Depemokimab, an investigational ultra-long-acting monoclonal antibody targeting interleukin-5 (IL-5), demonstrated significant improvements in nasal polyp size and nasal obstruction for patients with chronic rhinosinusitis with nasal polyps (CRSwNP). The trials showed that biannual depemokimab treatment outperformed placebo, with results observed early and sustained over 52 weeks.

In both trials, depemokimab achieved clinically meaningful reductions in nasal polyp score and nasal obstruction. A pooled analysis revealed significant treatment differences for nasal polyp score (-0.7) and nasal obstruction (-0.24), both showing p-values below 0.005. Secondary endpoints, including improvements in rhinorrhoea, loss of smell and sinus imaging, also favoured depemokimab.

The trials, involving 528 patients with inadequately controlled CRSwNP, demonstrated that 74% of patients in the depemokimab group avoided additional interventions like surgery or systemic corticosteroids (SCS), compared to 64% in the placebo group. Safety profiles were similar between both groups, with adverse event rates of 74% and 76% in the depemokimab arms of ANCHOR-1 and ANCHOR-2, respectively.

CRSwNP, a condition affecting up to 4% of the global population, is often poorly managed with current treatments like SCS and surgery. Depemokimab's results suggest a promising alternative, with regulatory filings in progress for its use in both asthma and CRSwNP.

These findings, also published in The Lancet, strengthen GSK's position in the biologic treatment space for type 2 inflammatory diseases. Depemokimab is not yet approved for either asthma or CRSwNP in any market.