SAN MATEO, CA – March 27, 2026 (GLOBE NEWSWIRE) – Navigator Medicines Inc., a clinical-stage biotech company pioneering best-in-class bispecific antibodies (bsAb) for inflammatory disorders and autoimmune diseases in areas of high unmet need, today announced it has initiated patient dosing in its Phase 2a MAINSAIL clinical trial evaluating NAV-240, for the treatment of HS. The company has also entered Phase 1 clinical development for its next generation HLE bsAb, NAV-242. This important progress follows positive results across the program presented at the American Academy of Dermatology Congress 2026 in Denver, Colorado, U.S.A.

“The simultaneous clinical advancement of NAV-240 and NAV-242 reflects the positive safety and tolerability profile of our potential best-in-disease bispecific antibody program,” said Tosh Butt, Chief Executive Officer, Navigator Medicines. “We are pleased to share data from across our OX40L/TNFα bispecific program at AAD as we strive to meaningfully raise the standard of care through both efficacy and dosing, for people living with the devastating symptoms of hidradenitis suppurativa.”

MAINSAIL, the Company’s first Phase 2a trial, is a multi-center, randomized, double-blind, placebo-controlled trial to assess the efficacy and safety of NAV-240 in adults living with moderate to severe HS. Efficacy including a reduction in abscesses, nodules, draining tunnels, as well as improvement in quality of life outcomes will be assessed. Recruitment for the program is ahead of expectations, reflecting enthusiasm for novel therapies in HS. Results are expected in H2 2027 to inform future development of both NAV-240 and NAV-242. Full details of the Phase 2a MAINSAIL trial can be accessed at www.clinicaltrials.gov (NCT 07384975).

Phase 1b Multiple Ascending Dose Study of NAV-240 (Poster P74215)
The clinical progress of NAV-240 builds on results from the multiple ascending dose (MAD) study which assessed the safety, tolerability, pharmacokinetics (PK), pharmacodynamics and immunogenicity of NAV-240 after repeat dosing in 24 healthy volunteers at various doses. NAV-240 demonstrated a favorable safety and tolerability profile, predictable PK and low rates of immunogenicity, consistent with the earlier single ascending dose study (SAD). Dose-dependent reductions in biomarkers were also observed. No treatment emergent adverse events (TEAEs) led to study discontinuation and no serious TEAEs were observed.

“Results of the Phase 1b study presented at AAD provide a strong foundation for NAV-240, confirming a safety and PK profile that enabled us to move confidently into Phase 2 development,” said Dana McClintock, M.D., Chief Medical Officer, Navigator Medicines. “Results from Phase 2a MAINSAIL combined with our broader development program will enable us to accelerate to pivotal studies with a potential best-in disease therapy.”

NAV-242, a Next-Generation, Half-Life Extended Bispecific Antibody
Navigator has achieved first participant dosed in the Phase 1 study of its next-generation subcutaneous therapeutic, NAV-242. The Phase 1a/1b portion will assess the safety, tolerability, PK, PD and immunogenicity through SAD and MAD in healthy participants. The phase 1c portion will evaluate the therapy in patients living with HS. Results of phase 1a are expected in Q4 2026.

This important progress follows promising pre-clinical data (Poster P74490) that showed enhanced stability and extended PK in vivo compared with NAV-240, suggesting that every other month or quarterly subcutaneous dosing of NAV-242 can be achieved. Engineered for extended half-life, NAV-242 offers the potential for a highly differentiated and preferred patient-friendly treatment option for patients with autoinflammatory conditions including HS, Crohn’s disease and ulcerative colitis.

About OX40L and TNFα Inhibition
NAV-240 and NAV-242 have been specifically engineered to simultaneously target OX40 ligand (OX40L) and TNFα, two individually validated targets in difficult-to-treat inflammatory disorders and autoimmune conditions, with recent data supporting the benefit of the combination in HS. By blocking OX40L, NAV-240 and NAV-242 dampen inflammation without compromising the baseline T-cell populations essential for long-term immune health.

About Hidradenitis Suppurativa
Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease, characterized by painful, recurrent abscesses and lesions. People with HS experience flare-ups of the disease as well as severe pain, which can have a major impact on quality of life.

HS affects three times more women than men, with global prevalence estimates1 of ~1% of the population based upon a meta-analysis of 25 trials across 23 countries, with recognized regional variability. Over one million people in the U.S. live with moderate-to-severe HS, with only 350,000 currently seeking treatment. Given the magnitude of disease burden and the potential introduction of several new biologics in the coming years, the opportunity to help people living with HS is projected to increase significantly over the next 5 years.

About Navigator Medicines
At Navigator Medicines, our mission is to bring new hope to people facing inflammatory disorders and autoimmune disease with high unmet needs. We advance best-in-class bsAb to address the daily challenge of chronic inflammation. Navigator Medicines was founded in 2024 as a subsidiary of Sera Medicines. Our mission is powered by a $100M Series A financing, co-led by RA Capital Management and Forbion, giving us the resources to pursue therapies for those who need them most.To learn more visit www.navigatormedicines.com.

Contacts:

Business or Investor Inquiries:

Mark McLaughlin

info@navigatormeds.com

Media Inquiries:
Arran Attridge

arran@attridgecomms.com

References
1. Bouazzi D, Nielsen SM, Hagan PG, et al. Prevalence of Hidradenitis Suppurativa: A Meta-Analysis of Global Hidradenitis Suppurativa Atlas Studies. JAMA Dermatol. Published online August 27, 2025. doi:10.1001/jamadermatol.2025.2373