Forlong Biotechnology to Present Clinical Data from the First-in-human Study for FL115 (IL-15 Superagonist) in US Patients with Advanced Solid Tumors at 2026 ASCO Annual Meeting

SHANGHAI & SUZHOU, China--(BUSINESS WIRE)--Forlong Biotechnology, a clinical-stage biotech company focusing on developing transformative cytokine therapies for patients with severe unmet needs, today announced a poster presentation at the upcoming 2026 American Society of Clinical Oncology (ASCO) Annual Meeting, which is being held from May 29 to June 2, 2026, at the McCormick Place in Chicago, IL.

The presentation will detail safety, pharmacokinetics, pharmacodynamics and antitumor activities of FL115 from the first-in-human FL115-101 study conducted at 3 investigational sites in US. First patient was dosed in December 2023, and the study was completed in September 2025 with total of 11 patients treated. One patient received the 1^st dose in Jul 2024, remained progression-free at the study completion, and afterwards has continued to receive FL115 treatment under a Single Patient IND Protocol/Treatment Plan.

Details of the poster presentation are as follows:

• Poster Board: 291
• Poster Title: Safety, pharmacokinetics (PK), pharmacodynamics (PD), and antitumor activities of FL115, a novel IL-15 superagonist, from the first-in-human study in patients with locally advanced/metastatic solid tumors.
• Session Type/Title: Developmental Therapeutics—Molecularly Targeted Agents and Tumor Biology
• Date and Time: May 30, 2026, 1:30 PM-4:30 PM CDT

About FL115

FL115 is an engineered IL-15/IL15Rα-Fbody fusion protein, aiming to enhance anti-tumor immunity via IL-15-mediated signaling on NK and CD8+ T cells while minimizing complexity from Fc. FL115 has demonstrated significant anti-tumor activities as a monotherapy or as part of combination therapy in vivo, and can be manufactured by a robust and efficient process with excellent product stability. Clinically, FL115 has demonstrated favorable safety profile and preliminary clinical responses as a monotherapy, and has the best-in-class potential to synergize with current and emerging T cell-targeting immunotherapies through combination therapy to significantly improve the treatment outcome for patients. It is currently being investigated in combination with Bacillus Calmette-Guérin (BCG) in a Phase 2 clinical trial to evaluate safety and preliminary efficacy in patients with nonmuscle invasive bladder cancer (NMIBC) and in combination with an anti-PD1 monoclonal antibody in a Phase 1b/2 clinical trial to evaluate safety and preliminary efficacy in patients with advanced solid tumors.

About Forlong Biotechnology

Forlong Biotechnology is a clinical-stage biotech company focusing on developing transformative cytokine therapies for cancer patients with severe unmet needs. It has established four proprietary synthetic immunology platforms: Fbody ® Long-acting Technology Platform, Fc engineering platform, Syntokine® Synthetic Cytokine Platform and AI-driven Intelligent Biomolecular Discovery Platform. The leading candidate FL115 is interleukin-15 (IL-15) superagonist with best-in-class potential, currently being advanced to combo therapy with PD-(L)1 antibodies in Phase I for patients with solid tumors and combo therapy with BCG in Phase II for patients with NMIBC. Its second candidate FL116 is a PD-1 antibody fused with interleukin-18（IL-18）mutein which is engineered to bind IL-18 receptor and not IL-18BP (a decoy), and has demonstrated potent tumor-killing efficacy in multiple in vivo tumor models resistant to immune checkpoint inhibitors.