EADV 2026: TNFα, OX40L Cluster at HS Draining Tunnels

Tumor necrosis factor alpha (TNFα) and OX40 ligand (OX40L) both cluster near cells surrounding draining tunnels in hidradenitis suppurativa (HS) skin, according to late-breaking spatial mapping data presented at the 2026 European Academy of Dermatology and Venereology (EADV) Congress in Vienna, Austria. Navigator Medicines, which supported the research, is developing 2 bispecific antibodies designed to block both targets simultaneously.¹

The company also presented early-phase safety data for its lead candidate, NAV-240, and preclinical findings for a longer-acting successor, NAV-242. A phase 2a trial of NAV-240 in HS is enrolling faster than anticipated, according to Navigator.¹

What Did the Spatial Mapping Study Find?

Johannes Griss, MD, PhD, an associate professor at the Medical University of Vienna, led the analysis of skin sections from patients with HS. Both TNFα and OX40L localized close to tunnel-associated cells, implicating the 2 pathways in disease pathology.¹

Griss presented the findings in a late-breaking session on October 1, 2026 (D2T01.4B). In the company's announcement, he said pinpointing where the immune response occurs in HS is essential for designing better therapies. He interpreted the concentration of both molecules at tunnel sites as evidence they work in concert to maintain inflammation, supporting continued investigation of dual-targeting agents.¹

Navigator suggested bispecific antibodies acting on both pathways could reduce inflammation specifically where tunnels form. Draining tunnels, also called sinus tracts or fistulas, develop beneath the skin in more advanced disease and contribute to pain, scarring, and daily burden.¹

What Did Early Data Show for NAV-240 and NAV-242?

A poster (P1749) reported translational data from phase 1 single and multiple ascending dose studies of NAV-240 in 64 healthy volunteers. According to the company, the agent showed acceptable safety and tolerability, low immunogenicity, and pharmacodynamic results consistent with its dual mechanism. Antiviral T-cell function was preserved, which Navigator described as important for long-term immune health.¹

A second poster (P1782) presented preclinical data showing NAV-242 had greater stability and longer in vivo pharmacokinetics than NAV-240. Early cohorts of an ongoing phase 1a/b study of subcutaneous NAV-242 in healthy participants have confirmed an extended half-life, the company reported. The analysis is evaluating safety, tolerability, pharmacokinetics, pharmacodynamics, and immunogenicity, with full results expected in the second half of 2027.¹

Tosh Butt, chief executive officer of Navigator Medicines, said the extended half-life of NAV-242 gives it potential for a differentiated dosing schedule.¹

What Comes Next for the Program?

The phase 2a MAINSAIL trial (NCT07384975) is a multicenter, randomized, double-blind, placebo-controlled study of NAV-240 in adults with moderate to severe HS. Investigators will assess changes in abscesses, nodules, and draining tunnels, along with quality of life outcomes.¹˒²

Navigator expects MAINSAIL results in the third quarter of 2027 and plans to use them to guide development of both NAV-240 and NAV-242.¹

Neither agent has been approved by any regulatory authority. The release did not provide numerical safety, pharmacokinetic, or half-life data, and the spatial mapping study did not report the number of patients or samples analyzed.

Editor’s note: This summary has been edited for grammar and clarity using artificial intelligence tools.

References

1. Navigator Medicines presents new data at EADV 2026 as bispecific antibody program advances at speed in hidradenitis suppurativa. News release. Navigator Medicines. September 29, 2026. Accessed October 5, 2026. https://www.navigatormedicines.com/pr_september-29-2026.

2. MAINSAIL: NAV-240 in moderate to severe hidradenitis suppurativa. ClinicalTrials.gov identifier: NCT07384975. Accessed October 5, 2026. https://clinicaltrials.gov/study/NCT07384975.